Monday, February 02, 2009

Crosman 1088 - Part 3

by B.B. Pelletier

Part 1
Part 2

Do you even remember that I was looking at the the Crosman 1088 pistol? It seems so long ago (Dec. 17) that I completed part 2.

In part 2, I mentioned that the single-action function doesn't work on this particular pistol. I could have replaced the gun right then, but I didn't. Now I have completed the accuracy part of the test and the results have been quite eye-opening. All shooting was double-action.

Also, here's an update on the CO2 piercing screw. We now know the 1088 loads gas silently. So I set out to see how few screw turns were necessary to pierce the CO2 cartridge, because any more than that would just stress the end seal, which is why the gun leaks after awhile. It just takes a single turn of the screw on the pistol I'm testing. Once I do that, I fire the gun in a safe direction to be sure the gas is flowing.

Test range
The test for pellet accuracy was shot at 10 yards. I know I said I would shoot at 20 for the guy who wanted the Kodiak pellets tested, but the winter weather just hasn't cooperated. If this test was going to be completed now, it had to be shot indoors.

Beeman Kodiaks
The Beeman Kodiak pellet was recommended for long-range accuracy with a 1088, but at 10 yards it isn't the best in this pistol. The groups ranged around two inches for eight shots. The Kodiaks were also the slowest pellet I tried. I could hear how slow they traveled to the pellet trap compared to all other pellets.

Crosman Silver Eagles
Crosman Silver Eagle hollowpoint pellets were only a little less accurate than Kodiaks. They added another half-inch at 10 yards. And unlike the Kodiaks, they were noticeably faster.

RWS Basics
RWS Basic pellets were a big improvement over the Kodiaks, grouping about 1-5/8 inches for eight shots. That sounds big, but it looks impressive compared to the others that went before.


RWS Basic pellets showed promise in the 1088.


RWS Supermags
But RWS Supermags blew the cover off the jar. The first group I shot measures less than one inch! The next group opened up to 1.5 inches, but that's not too shabby! Remember, I'm shooting double-action supported at 30 feet.


The first group shot with RWS Supermags was phenomenal. Some of the holes are square because I had to bend the paper back so they would show.



Second group of Supermags wasn't as good as the first, but it's still very nice.


And then I shot BBs
The 1088 is also a BB gun, so I had to shoot them, as well. I didn't have high hopes, because my experience tells me guns made for both BBs and pellets are a compromise. The 1088 had other plans. Eight Crosman Copperhead BBs shot offhand at 15 feet with a center hold sailed through the center of the bullseye, leaving a one-inch group behind. I know the distance is just half, but these are round BBs, and they cannot be expected to shoot accurately at long range. The center hold was just to keep the BBs inside the trap, but when I saw the target I realized this group was as good as the group shot with the SIG Sauer SP 2022 BB pistol I tested for you. If I recall, I said that one was the most accurate BB pistol I'd ever tested. So, guess what? The 1088 joins that club. I'm very impressed with the accuracy of this gun with BBs.


Here are 8 BBs shot from 15 feet using a center hold. They're one inch or just slightly more. This is remarkable accuracy for a BB pistol!


Bottom line? The 1088 is a keeper. Buy it and shoot it. Just remember to not screw that tightening screw very tight, and the gun should last a long time.

68 Comments:

At February 02, 2009 6:45 AM, Anonymous Anonymous said...

Can someone explain what single or double action means when shooting a pistol like the Crossman 1088. I looked at some previous posts and could not find an answer to this I could fully understand.

Thanks,

Aaron

 
At February 02, 2009 7:16 AM, Blogger Thorin said...

Airguns of this type are essentially a double action revolver. Shooting single action means that you cock the hammer first, so that the trigger pull only releases it, doing a single task or action. In double action shooting, the trigger pull firts cocks the hammer and then releases it, doing two tasks.

 
At February 02, 2009 8:07 AM, Blogger B.B. Pelletier said...

Aaron,

Read this post:

http://www.pyramydair.com/blog/2006/04/what-do-single-action-and-double.html

B.B.

 
At February 02, 2009 8:18 AM, Anonymous Vince said...

Aaron, if you look at 'Part 1' you'll see that the magazine is a rotary type that is very similar to the cylinder on a revolver, and works the same way. That's why Thorin calls the gun a revolver - under the skin, that is exactly what it is.

The only thing he left out is that the trigger pull also indexes the internal cylinder/magazine, rotating it to bring the next shot in line with the barrel. On a 'standard' revolver (like Crosman's 357) the magazine is indexed as the hammer is moved back into the cocked position. On the 1088 (like its 1008 predecessor) the cylinder/magazine is indexed by the trigger pull, even if you cocked the hammer manually.

Because of that a 'regular' revolver usually has a much lighter trigger pull when fired in 'single action' mode - all it's doing is releasing the hammer instead of cocking the hammer/indexing the cylinder/releasing the hammer. On the 1088, though, the trigger is still indexing the cylinder and releasing the hammer, so the improvement in single-action mode isn't as great.

 
At February 02, 2009 9:12 AM, Anonymous volvo said...

Kevin,

Your question from the other day – since I’m not currently in the market for any new springers I’m not sure if the .20 cal R-1 has been up for awhile. I know Paul’s stuff does not usually last long, but a $1750 R-1 may take a little longer to find a home. I’m sure it’s worth ever penny.

I had a Santa Rosa R-1 I used as a trade – tried to be first in line when it was customized but he said it was already spoken for the day he received it.

One of the many lesson from his site is that he seeks HW \ Beeman rifles for his custom work.

 
At February 02, 2009 9:42 AM, Blogger CJr said...

B.B.,
I will presume to know the answer to this question but still want your expert opinion...your experience with the piercing screw has me concerned. Are you giving us a lesson on how to treat CO2 piercing screws on ALL guns? I think so!

I have a S&W 586 that I have always screwed as tight as I could before closing the piercing lever. This now sounds like a bad idea and I will stop doing that unless you say otherwise.

I have shot, maybe, 10 CO2 cartridges so far. Is that enough to cause any damage?

Also, during cartridge replacement, I put a drop of Pellgunoil in the end seal rather than on the tip of the CO2 cartridge itself. Is this a good practice or same/same?
-Chuck

 
At February 02, 2009 10:06 AM, Blogger B.B. Pelletier said...

Chuck,

Yes, my advice is for all CO2 cartridges. What they tell smokers who quit applies here, as well. The sooner you stop what you are doing, the less damage you will have done. Your gun won't heal, but by all means do it this way from now on.

I also drop the oil into the end seal on many guns. Same same.

B.B.

 
At February 02, 2009 10:27 AM, Anonymous Anonymous said...

Thorin, Vince, BB -

Thanks for the info. I think I get it now. single action simply release the hammer once you've cocked the pistol. Double action not only releases the hammer but first rotates the clip to chamber the pellet.

Thanks again guys,

Aaron

P.S. My word verification was the word "bills", which is funny to me because that's the reason I haven't ordered any airgun stuff lately!

 
At February 02, 2009 10:57 AM, Blogger CJr said...

Thanks B.B. for the CO2 advice. You have saved my pistol'e for many more days.

I've been trying to play catch-up on all your blogs since March 2005 and it is tough. So, I thought I would just read the B.B. posts and forget the comments since that's where 90% of my time is consumed.

Well, while skimming posts,I accidentally read the comment that mentioned the worm inflater. I would have hated to have missed out on that. So now I don't feel comfortable skipping all the comments. Some of those posts have over 450 comments!! Oh, help me, help me! Somebody put them on tape so I can listen to them in my sleep.

-Chuck

 
At February 02, 2009 11:23 AM, Anonymous Anonymous said...

Kevin and Wayne:
Thanks for your response guys... I'll check the site ASAP!!! Take care!!
Cheers,
Jony

P.S.: This is for the previous post!! LOL...

 
At February 02, 2009 11:44 AM, Anonymous Vince said...

Aaron, in general use the term 'single action' or 'double action' only refers to the hammer action, not the rotation of the clip. That's why the 1088 can be considered to have a single-action mode, even though the trigger is doing two things. I was only pointing out that in terms of trigger feel, on a pistol like this you don't gain as much when in single-action mode as you do on a normal revolver.

Yeah - it might not be a true 'single action' since the trigger still does 2 things, but that's what it's called if you cock the hammer first.

 
At February 02, 2009 11:47 AM, Anonymous Anonymous said...

B.B.

That's good to know about CO2 cylinders. I have been cranking them into my 1077 in the belief that more force makes a tighter seal and is better for the gun.

Matt61

 
At February 02, 2009 12:51 PM, Blogger Revwarnut said...

On thing about using BBs in the 1088 to be aware of.
The stock Crosman cylinder you receive with the gun. (and the ONLY one sadly...) has a magnet in it to hold the pellets as BB pointed out. However, the inexpensive 3-piece magazine packs you can buy for it do NOT have the magnet and so they do not hold the BB anywhere near as well as the Crosman ones. (which I have had a very hard time finding...)

And for Chuck/CRj, I hope you find that "worm inflator" useful. For those who did not see that. I suggested using a worm inflator I found in the fishing department as an oiler for hard to reach spots in your guns. It has a metal tube in a plastic squeeze bottle that extends your oiling reach. I would recommend filing down the sharp point on it of course.

Bruce

 
At February 02, 2009 1:10 PM, Anonymous Anonymous said...

B.B.

Hold everything. The PA listing for the new Crosman Challenger PCP says that the max velocity is 530 fps. I thought it was adjustable. This is putting a big crimp in my fantasies.

Matt61

 
At February 02, 2009 1:18 PM, Anonymous Anonymous said...

B.B.

More discoveries by me. I had thought that the fantastic savings for the Discovery came from both the rifle and the pump. However, it looks like the Discovery pump alone is more than the Air Force pump which can give you an extra 3000 psi. If this is true, then the Discovery rifle is an even better deal than I thought, and it also appears that the new rifles on the Discovery platform don't represent significant new savings. They are more expensive than the Air Force Talon although I suppose not so much as the S410, and the pump must be bought separately for an additional $200. Am I right about this?

Matt61

 
At February 02, 2009 1:39 PM, Blogger B.B. Pelletier said...

Matt,

SLOW DOWN!!!

The CROSMAN Challenger is a 10-meter rifle. OF COURSE is will be under 600 f.p.s. THEY ALL ARE -- EVEN THE $3,000 ones!

The BENJAMIN Marauder is a different rifle altogether. That the rifle you are probably thinking of.

The Discovery is a suoer buy! I've been saying that since it came out. And the pump is the same one that AirForce sells, only with different connections. It will also pump to 3,600 psi.

Got it?

B.B.

 
At February 02, 2009 1:47 PM, Anonymous Anonymous said...

Vince - Thanks again. This blog is awesome and so are those who read and contribute to it.

Just for fun I hung a picture of the AA TX 200 MK III in my cube at work today.

I think staring at that rifle everyday is going to make the decision of how to spend this years income tax return very easy...

I can't wait

Thanks again,

Aaron

 
At February 02, 2009 1:57 PM, Anonymous Anonymous said...

BB,
Thanks for the report. Now for the accuracy of this new production pro77. As I said in my last post, there are some major differences, mainly the mat black finish and washers. I took it out at 40ft yesterday and the first 5shots hit 1inch. Unfortunately, the first clip in this pistol was the most accurate, after that, groups were just under 2.5inches. I think the slide interferes with the barrel when it gets low co2. Certainly more accurate than my first early production pro 77.
Shadow express dude

 
At February 02, 2009 2:07 PM, Anonymous Dr. G. said...

Re.. .. ..Pellet Grouping .... .. .

The other day there was some speculation as to why different pellets group at different points apparently not totally as a function of speed, in that there is lateral and not just vertical movement in what ends up on the paper.

After considerable thought about this subject, which includes lots of information garnered from this blog and from related books, I have a simple hypothesis which is probably the actual explanation (primarily because there is no other logical explanation - there are not a whole lot of changing variables here). This hypothesis is easily testable by any shooter reading this who is interested and has the time.

Let me know if you are interested in testing it, and I will explain further. I believe it has more to do with artillery than rocketry, by the way.

- Dr. G.

 
At February 02, 2009 2:09 PM, Anonymous Dr. G. said...

B.B.,

When you have the time, please address my questions from the end of yesterday's comments regarding the Nightstalker.

Thanx.

- Dr. G.

 
At February 02, 2009 2:13 PM, Blogger B.B. Pelletier said...

Dr. G.,

Can anything be done to improve a NightStalker trigger? Probably, but the NightStalker is such a low-priced gun that nobody has done anything about it. Or if they have, I don't know about it.

But I'm sure that an airgunsmith could find a way to improve that trigger. Never say never.

B.B.

 
At February 02, 2009 2:21 PM, Anonymous volvo said...

The new Hawke scope from PA arrived and the Cyclone should not be far behind. Needless to say I have very high hopes going in.

I partially blame Wayne for my current quest; I want to find a PCP that inspires me as much as his AA does him. Here are some of the other reasons:

While I rate the FX Whisper a keeper and it fills the niche I needed it for exactly, I don’t love it. I like it a lot. First, polymer stocks are actually preferred by many but they just don’t inspire me. Tastes differ- some guys are into Jennifer, some Angelina, and a few perhaps Aunt Bee.

I like a wooden stick. The youngest of 5 baby boomers I grew up in the transition period. Cowboys and Indians were fading out and Mattel was offering an M-16. The jingle from the TV commercial said “ the greatest gun you’re ever seen” but I had my doubts. (Could you imagine that ad on TV now?) Here is a print ad for the M-16:

http://pzrservices.typepad.com/vintageadvertising/2007/07/ad-for-mattels-.html

We mostly used the Daisy that looked like a Western Carbine and made quiet a crack. Pretty sure the stocks were plastic but still looked like wood. I will give polymer credit for lighter weight, durability, weather resistance, and the ability to appear new longer – but the tactical look just isn’t my thing.

On the other end of the spectrum when I see the gorgeous custom stocks I have to admit I would be afraid to handle the rifle. I have tried to keep guns, cars, etc like new but I know it is just not possible if they are to actually be used. So my new girl will be sporting an attractive but usable piece of lumber instead of polymer or high-end exotic.

Next is the power level. The Whisper with heaviest in caliber .177 pellets gives about 900fps and a little over 18 ft-lbs. That is perfect for populated areas and I would guess also helps maintain the quiet mantra, plus keeps the gun very accurate. (It has a strong dislike for light pellets that it tosses over 1000 fps.) But my intentions when I sold my 28 ft Patriot were that a PCP with even more horsepower would replace it. (The Whisper is the PCP replacement for my .177 R-1 and does it well)

Finally, it also lacks some of the “gadgets” available. The fill gauge, adjustable power, and detachable air tube.. I took a minimalist approach on my first PCP with the Webley Raider, rock solid and rock simple – but that was always intended as a stepping-stone.
My hopes are the FX Cyclone in .22 cal will be the island paradise. I think I hear a UPS truck…

 
At February 02, 2009 2:22 PM, Anonymous Anonymous said...

B.B.

Yes, I guess I read too much into this statement on the Airguns of Arizona blog about the new rifles:

"Featuring an adjustable striker travel and spring system, the Challenger PCP will allow for velocity control adjustments to offer proper performance, no matter the competition format."

This must mean adjustments within a 10 meter format although I don't know why they bother. I had fantasized this into a FT gun. That's what I get for looking at another blog....

And the Air Force Edge leaps back into preeminence as the new budget pcp target rifle. I do believe that Daisy must be having a fit. After long domination, the Daisy 853 looks to be swept away by the new offerings and if Daisy is as stodgy as I've heard, they probably don't have a new one on the drawing boards and won't be in the running for some time.

Dr. G. Bring on your hypothesis. I'll see if it can explain my very weird experience. I couldn't figure out why my B30 was giving large sloppy groups. Then I finally realized that the JSB Exacts that I had switched to from the Beeman Field Target specials were shooting to the left and slightly up at a distance of 16MOA. At 15 feet, the difference is subtle enough that I had subconsciously developed a slight jerk to move the pellets on target but was not always consistent. Now that I've adjusted the sights, the rifle is dropping the pellets on target. Who would have thought that different pellet types of the same caliber would diverse by so much. It doesn't seem aerodynamically possible. Beware of expecting logic to get to the bottom of this subject... It seems hugely complicated.

Matt61

 
At February 02, 2009 2:52 PM, Blogger CJr said...

B.B.,
Based on your review of the IZH-61 back in Sept 2007 and my poor eyesight, I bought some peep sights to try out. I want to pass some info onto you and others who are looking for sighting options for the 61.

These results are based on sighting in at 10m.

I have four 61s, one of them is scoped with the BugBuster 6X and this is an excellent fit with the UTG 11mm to Weaver Adapter from PA (Item#:MNT-PMTOWL[PY-A-2401]) to prevent creep. I had to correct for a lot of scope drop on this setup.

The "peep" sights seem to be the reverse of the scope and have a lot of scope "lift" except for the Mendoza!

I installed the Beeman Sport Aperture on one of the rifles and tried to sight it in. I could not get in any closer than 1.5" ABOVE the bull with the sight adjusted down to the max. I then mounted it on another 61 and was able to get it down to 1/4" BELOW the bull at max down! Since it works acceptably on the second 61 I'll leave it there and not test it on the third. I did double check the mounting on both rifles to make sure the clamps were in the rail properly. Also, this sight seems to mount canted to the left and I had to adjust windage a few clicks to get on target. This sight has ZERO scope creep - I think because it has 2 screws along the length of the base.

The third rifle has the Avanti Precision Diopter sight and it works good but I had to adjust it all the way down, as well. I had to adjust windage on it, also, but only one or two clicks. This sight has only one screw on the base and it may have creeped 1/32" since I mounted it. I gave the screw another crank with pliers so maybe that'll take care of that.

I put the Mendoza Diopter sight on one of the rifles a month ago and could not correct for scope drop. I reported this in a comment to a previous post. I sent it back. I don't know which rifle it was. I'm confused as to why the Mendoza was sighting below the bull yet the others tend to sight above the bull.

As far as use: I like construction of all of them but with my eyesight the Avanti works best. The Beeman has a larger aperture so I don't get so much of the "pin hole" effect. I get a fuzzy sight picture with or without glasses. I'm near-sighted. The Avanti has a smaller aperture and thus I can see the sights and target much clearer but it looks like I'm looking down a tube and the target looks so much smaller than through the Beeman. With such a small picture of the target I can't get any precision. Don't look for me on the competition trail.

I was hoping for better sight pictures but I may have to be satisfied with the scope. I have had marginal success with contact lenses but they're not good enough to compete.

-Chuck

 
At February 02, 2009 3:18 PM, Anonymous Anonymous said...

Chuck,

That's quite the armory of IZH 61s. Thanks for your experience with the different sights. You're a better man than I am because I couldn't get any of the open sights to fit or align on my rifle. However, the Bug Buster scope works great, and I didn't bother with a Weaver adapter. I just bolted it on with medium Accushot mounts and the scope has never deviated in 20,000 odd shots. A good scope and rifle combination is something to treasure.

Matt61

 
At February 02, 2009 3:26 PM, Blogger B.B. Pelletier said...

Chuck,

Thank you for that compatibility report. That should be a blog, don't you think?

B.B.

 
At February 02, 2009 3:39 PM, Blogger CJr said...

B.B. Re: blog

I could do that. After I published the comment that thought ran through my mind. When I started that comment I didn't mean it to be so long but one thing led to another and here we are.
-Chuck

 
At February 02, 2009 4:13 PM, Blogger B.B. Pelletier said...

CJr,

Go ahead and start expanding your work, but there is something that's going to change how things get published pretty soon. So instead of sending in a guest blog, we may do something else with this subject.

The value of this info it the same as a compatibility chary for air filters at the car parts store. So the specific links to the products you mention sre important to be embedded in the article.

B.B.

 
At February 02, 2009 4:28 PM, Blogger Felice Luftschein said...

CJr, you can get different aperture discs for the Beeman sight, they sell one that's about .05", you probably have the .12" or .09" hole on yours. You can also get a Merit adjustable disc for about $50.00

Nick

 
At February 02, 2009 5:10 PM, Blogger CJr said...

Nick,
Thanks for the info. I'll certainly check into that. I just know there has to be an answer to my dilemma.

-Chuck

 
At February 02, 2009 5:46 PM, Anonymous Dr. G. said...

Matt#61,

Re: ...Pelllet Grouping...

I will try to be concise, but not being able to write this in simple mathematical language may prevent this...

When the Whiscombe is adjusted in very small increments, the groups move around the clock face at a given distance. They move around at different rates depending on the pellet. That is your hint.

Remember that pellets move around an imaginary center axis from your barrel end to the paper as they move through the air, and it turns out that each pellet describes uniquely different (tighter, loser; faster, slower) spirals as a function of the barrel, speed, and pellet.

To test the hypothesis, see if the POI of your pellet and gun moves around a clock face as you adjust the distances, e.g. 20, 30, 35, 50, 90 feet.

It is also possible that around this spiral that is known, each pellet's spiral is tracing a larger, slower spiral. I suspect that this may be the case, as I notice that the faster shooting airguns are always more accurate than the slower shooting ones at distances of over 25 yards, but the opposite occurs below 25 yards (about). So, I suspect a slower moving rotation (or revolution) is at work. Same effect, same test.

- Dr. G.

 
At February 02, 2009 6:07 PM, Blogger CJr said...

Thank you Dr. G.,
By Jove, I think you've got something there! That is a very good explanation of what is going on. I understood you very well without the math :) You did a good job! I wonder if a strobe light would pic that up? Anybody got one? And a high speed camera?
-Chuck

 
At February 02, 2009 6:19 PM, Blogger CJr said...

BTW,
In my testing of the different pellets, only the JSB, the one I used as the standard, was domed. Now, if they could just get it to make a neat wadcutter hole.
-Chuck

 
At February 02, 2009 7:17 PM, Anonymous BG_Farmer said...

Dr. G.

I think you're on to something. My suspicion is the difference b/t high velocity and low velocity pellets at different ranges is one of stabilization, i.e. higher speed pellets are spinning too fast ("over-stabilized") at short ranges and lower speed pellets are spinning too slowly at long ranges ("under-stabilized"). I'm still not convinced that spin stabilization is necessary for diabolo ("drag-stabilized") pellets at all, but that's a different discussion. If you didn't see the links I posted a long while back, there are actual traces of bullets following spiral paths of differing stability taken by high-speed camera (by a forensic specialist). I'll re-find it and post a link if you're interested.

Matt,
I'm bummed about the Challenger, too, if its only a 10M gun. Although I am rich and famous, I can't justify multiple PCP's. Also I dislike having more than one rifle of one caliber, even if I have indulged in a couple of springers. Smacks of "enthusiast" or "collector"...I just like to shoot things:). What does benzene taste like?

Fred,
I saw your note about the telescope. An Edmund Scientific reflector on a pedestal ("pipe with legs") mount and clock drive is a really nice setup. Do you know the f/ratio? BB ought to take you up on the offer, if he didn't while I was on ice.

 
At February 02, 2009 7:37 PM, Anonymous Dr. G. said...

Chuck,

Instead of cameras and strobes, simply shoot on a calm day at the different distances and see if the pellet that you are shooting forms groups around a clock as a function of distance. Easy test, will take you under an hour to do it right.

Or just ask B.B. Artilliere, and he will tell you....might be faster.

- Dr. G.

 
At February 02, 2009 8:17 PM, Anonymous Anonymous said...

Dr. G.

This reminds me of the discussion I had with BG_Farmer, Herb, and B.B. about spiral paths. I think we all agreed about the spiral shape of the paths due, according to Mann's book The Bullet's Flight from Powder to Target, to imperfections in lead which will move the projectile's center of mass off-axis and cause it to wobble in flight. We differed, though, on the degree of spiral, and how much it contributed to group size.

My own idea is that the wobble/spiral took place more or less in the tube swept out by the pellet, perhaps deforming it somewhat but not necessarily turning the path itself into a spiral. BG_Farmer took a different view that the spiral equated to the diameter of group sizes. I still don't see how that could be since if you scaled up common group sizes for centerfire rifles at 100 yard to 600 yards, you get giant diameters which would make accuracy impossible.

Your idea seems to take a middle ground by suggesting that the spiral is small enough to lie within group sizes at a given distance but large enough to affect their placement at different distances. I'm still skeptical for essentially the same reasons as before. The movement at the distances you mention seems to scale up to be too large so that I don't see how FT shooters could make their longer shots, especially for those targets that are a quarter inch at 50 yards. If they were doing this, surely we would have heard about such a factor by now in addition to wind, pellet drop, and the Magnus Effect. Perhaps this could be another test. B.B. tells me that good FT shooters have their trajectories worked out ahead of time for every measurable distance within a FT course. So, do they automatically change windage with distance independent of whether there is wind?

On the other hand, I'm not able to explain the effect that you observed. Jane, where are you. Maybe you can shed some light on this.

Matt61

 
At February 02, 2009 8:19 PM, Anonymous Anonymous said...

BG_Farmer,

I don't know what benzene tastes like, but maybe Herb does.

Matt61

 
At February 02, 2009 8:35 PM, Anonymous Herb said...

BG-Farmer

Re: I'm still not convinced that spin stabilization is necessary for diabolo ("drag-stabilized") pellets at all...

I got a Crosman 760 (which has a smooth barrel right?) just to play with this. In the 760 a diabolo pellet shoots much better than a ball (0.177 lead ball, not BB which is wrong size for barrel), but a gun like the Dasiy 880 which has rifling does even better.

(As a side note is there any rifle with a smooth barrel for pellets which is a bit nicer gun? I don't have Bill Gates fortune to commision a factory to make me a smooth Talon SS barrel. Can't even justify Talon SS yet...)

Like Einstein said - "It's all relative..."

There are multiple factors happening as the pellet flies. I'd guess that the first three in order are:

* Plain ballistic path. Muzzle velocity, mass, gravity.

Assume POI determined by Random errors in X-Y axis path (range is z). All pellets produce patterns not groups.

* The diabolo shape stabilizes flight by increasing drag of skirt.

Stability traded off for range, introduces basic air friction. Random errors made smaller, can now see differences between different pellet designs.

* The spin averages out imperfections of the pellet. (spin averaging vs spinning too fast which creates curved path) Thus pellet to pellet variation reduced within the same pellet type.

I'd agree that spinning isn't something which has been studied enough. Unlikely that the current twist rate from 22 firearms is the right twist for pellet guns. Also unlikely that a low powered gun like my Daisy 22SG, and a really powerful gun like the Talon SS should have the same twist rate. A lot of money to research "perfect" - good enough just has us using same twist rate from 22 firearms.

I've had a couple of thoughts on this too. I'm trying to write an article which may be good enough for a blog. It might get some additional chatter at least.

I'm convinced that there isn't any one simple explanation. In others words, if there was one simple explanation, then the hundreds of years of shooters before me would have already figured it out. The fact that ammo/gun matching is still such an art indicates that they haven't. I've read for years where conspiracy theorists have postulated that the big car companies knew how to make a car go 60,100,200 (pick a number) miles on a gallon of gas, but just didn't want to make it. Hogwash. If some company knew how to make perfect barrel and ammo, they would have done it already. So there are no simple explanations. (I also don't believe in time travel - If it could occur, why have we not seen "tourists" from the future?)

Herb

 
At February 02, 2009 8:40 PM, Anonymous BG_Farmer said...

Matt,
If its in gasoline, I've probably tasted it. Diesel, also. Not on purpose, by the way:). In the the old days, they supposedly used kerosene and sugar as a cough syrup, supposed to work well. My grandfather claimed to have used it as a kid, but he didn't live past 90...

 
At February 02, 2009 9:09 PM, Anonymous BG_Farmer said...

Herb,

I'm looking forward to your article. The gyroscopic explanation is about the only one that has explained anything to me; otherwise, it seems too much like quantum mechanics. Obviously imperfections in barrel, rifle, etc. magnify or distort the effects, so even relative perfection is regrettably unobtainable.

I agree that the rifling rates on pellet rifles are, if necessary, probably not close to optimal for every pellet's material and BC, SD, etc.

The best testbed would be an FWB 700 with smooth bore...I can't afford it either, not even for science:). Maybe a 760 with a rifled barrel (there's still one model I think) versus 760 w/o rifling would be instructive, as I think the 880 may simply be made to relatively tighter tolerances or at least there's always that objection.

Also, maybe Shadow Express Dude can help -- he uses his shotgun with pellets, too, I think.

 
At February 02, 2009 10:36 PM, Blogger kevin said...

Herb,

I've been reading your analysis and speculation with great interest. I respect your obvious educated analysis and therefor appreciate your conclusions without "bill gates" budget to confirm with double blind tests. I think you're on to something and would appreciate a blog even if it's speculation and hypothetical.

Forgive this country boy from trying to simplify.

I can't help but think of that sinking ball, or curve ball that Jony threw at me in high school that I could never hit. That sob.

Is it possible that because of the uneven impact of air at the transfor port, or imperfect pellet seating, or imperfect rifling, or a burr at the leade or exit point of the muzzle or? and/or any of the above that the pellets affect on spin rate could be affected to the point of amplifying its' trajectory to strike low, right, high, left or a combination of any/all?

Am I oversimplyfying? Johnny or June help me.

kevin

 
At February 02, 2009 11:18 PM, Anonymous Anonymous said...

Herb,

This all sounds plausible except that it is not intuitive to me that spin would average out an imperfection. Wouldn't the opposite be true? Once a top starts to wobble, it doesn't correct itself.

Kevin, I have no doubt that some form of imperfection causes a projectile to deviate but whether that deviation is caused by the effect on spin I couldn't say.

BG_Farmer, maybe the glue and gasoline sniffers know something we don't. By the way, I don't think I saw your answer to my question about which springers you own. With all this talk of PCPs, I need a bit of reinforcement.

Heavy duty analysis of shooting problems makes me think we should all steer clear of the character Gus McRae from Larry McMurtry's western, Lonesome Dove. (It was made into a movie with Robert Duvall.) Gus says: "I would love the chance to shoot at an educated man"....

Matt61

 
At February 02, 2009 11:25 PM, Anonymous Herb said...

BG_Farmer,

RE: ... the rifling rates on pellet rifles are, if necessary,...

if necessary ??

To me there is no question that the standard 22 firearm twist rate is better than none. The manufacturers are not stupid. If a smooth bore was better than rifled bore, then that is what they would be making and selling, at least to competition target shooters. Good targets shooters are buying precision, and are not just going to accept marketing hype. The rest of us sheep would follow.

Also I'm pretty safe to assume that (1) that a smooth bore would be easier/cheaper to make, and (2) that businesses want to make most money possible, so from the "greed" factor too, they'd rather make smooth bores.

Rather I think that the pellet/barrel/power combination is so fussy that choosing a single "perfect" twist rate, or style, is futile. No twist rate is going to make every pellet shoot one hole groups at 50 yards. But if you want to shoot a 0.177 JSB Exact, at 500 FPS, then the standard 22 firearm twist rate almost certainly isn't the best either.

The point is that Tom has stated numerous times that the 800-900 fps range is the "sweet" spot for pellets. Let's pick 850 fps. Now what is the best twist rate for our JSB's? How much would it improve group size? (I'd better some, but certainly not ten times better...I'd also bet that I don't shoot good enough to notice.)

The article that I started is on POI shift not spinning per sey. Have articles on three different subjects in the works, ought to finish at least one. :-(

The Daisy Avanti Champion is a smooth bore BB gun. Supposedly best BB gun in world. Couldn't someone make a better BB gun by using a rifled barrel?

NO!! - The BBs are steel - they are too hard for rifling to "bite." So a smooth bore is the only way to go.

Kevin,

I think that your basic notion is right. First let me define my own terms.

Spin - the rotation of the pellet about its own internal central axis. Pure spinning would cause a "simple" curved flight.

Nutation - the rate at which the pellet is precessing (wobbling) along its ballistic flight path. Nutation would cause a corkscrew. As nose of pellet wobbles around, the pellet changes direction.

So the barrel rifling makes the pellet spin. Easy and straight forward enough.

But what would cause the nutation of the pellet?

As the pellet leaves the barrel, there is pressure still in the barrel. The muzzle blast is noise cause by that air exiting between the end of the barrel and the back of the pellet. Thus the pellet get a "kick in the behind" from the muzzle blast. Because of all the imperfections, this would cause the pellet to tip one way or the other. Slight imperfections in the rotation center of gravity would cause the pellet nutation also.

I think the low barrel pressure, and hence low muzzle blast, is why target shooters like about 500 fps. Balance between minimizing drop, and low nutation due to muzzle blast. FPS going to vary a bit anyway. Slower pellet is dropping like a rock when it gets to target, faster the muzzle blast kicks the pellet all over the place. Of course 500 fps is for 10 meters. 650 for 20 meters? and so on.


Herb

 
At February 02, 2009 11:28 PM, Anonymous wayne said...

Evening everyone,

Great topic today.. That 1088 is similar to the crosman 2210 I got last week, It's just ok to me.. It's "like all plastic" man.. They're fine for the price point....

I'm liking the 150 a lot.. the 600 is very nice too, maybe best built of the crosman so far.. But my favorite is still the S&W 586...(some serious use of metal there!!) now with the 8" barrel.. it shoots groups with the crosman 2300s.. but does it 5 times as fast!!! The sights are not fancy, but solid as hell!! and both mine came from the box shooting great groups.. just a little tweek here and there..

I think you guys are on to something as well, with the pellet speed/spin rate.. and the distance being shot... It seems that's why the round nose do well at longer distance, at certain speeds, and not as well slower or faster..

And the best in most of my guns at 60 yards plus, the kodiak either in .22 or .177, looks like the perfect shape and weight balance, for a long, slower journey to the target in a more controlled spin and speed...

I don't know.. just a guess for the reason, to explain the good results of that pellet on the real long shots...

Wayne

 
At February 02, 2009 11:33 PM, Anonymous BG_Farmer said...

Herb,
I'm not sure that spinning a stable pellet does any good either, except introduce more random effects.

Matt,
I tried some things as a youngster, but kids these days take the cake:). Must you really tell someone not to inhale spray paint:)?

Hammerli 490 and QB36-2. I also can use my wife's QB88.

Was Kevin trying to say he shot a man in Reno just to watch him die? There was a definite Cash reference there:).

 
At February 02, 2009 11:37 PM, Anonymous volvo said...

Kevin,

My initial impress of the .22 cal Cyclone is extremely positive. We have only had a few hours together but if I needed to describe her in two words it would be “silky smooth”

The side lever, trigger and even the safety all operate with minimal effort. The only stiff piece is the power adjuster and it’s nowhere near difficult.

Accuracy has been outstanding with both heavy and light pellets, a pleasant surprise. I have not had nearly enough time to test all the possibilities but here is a little data:

Kodiaks: Low - 14.2 ft lbs, Med - 22.3 ft lbs, and High - 31.8 ft lbs.

A standard weight pellet like the Beeman FTS goes 988 fps on high and 640 fps on low.

I’m trying to find an accurate pellet on low power with the same POI as Kodiaks on high power. I think that would be ideal. (Elevation only, no windage issues)

What I have concluded is that I need a compressor. I am one tired camper. The air tube states it is rated to 300 bar, the receiver says not to fill past 220 bar, but I am a 180-190 man.
I don’t even need to look; I can feel the spot with all three of my PCP and stop.

 
At February 02, 2009 11:57 PM, Anonymous volvo said...

Wayne,

You are correct about Kodiaks sailing at long distances, as they have a good ballistic co-efficient. It would be a nice touch if PA would add BC’s for all the pellets it carries.

Bg-farmer,

Not sure what the Johnny Cash reference was about, but I have to wonder also.

 
At February 02, 2009 11:59 PM, Anonymous Herb said...

BG_Farmer,

Re: "... not sure that spinning a stable pellet does any good ..."

Couldn't agree more. The correct idea is that you spin unstable pellets in order to stabilize them. There would be no point in spinning a "stable" pellet.

I bought a 4 foot clear plastic cover that goes over fluorescent lights to keep glass from falling in case of breakage. Put stopper in one end and filled it with water. Dropped non-spinning pellet into column of water and watched pellet nutate to bottom of tube. What can I say. I'm easily amused.

Spinning stabilizes pellet against nutation. Think of a top when you were a kid. The top spins straight when it is spinning fast. But as it slows, some intermittent friction causes the top to destabilize and the top starts to precess. as the top gets slower the precession turns into a wobble. Then the top falls over.

Herb

 
At February 03, 2009 12:03 AM, Anonymous Anonymous said...

Maybe PA should change multiple tin policy.

With every three tins, they give us a top.

:-)

Herb

 
At February 03, 2009 12:11 AM, Anonymous Anonymous said...

Cute diagram at:

http://www.arld1.com/images/swfs/nutation.swf

Herb

 
At February 03, 2009 12:14 AM, Anonymous BG_Farmer said...

Herb,

You type too fast:). I'll consider your point about nutation, although the drag from the skirt should also counteract that, given adequate velocity, without resort to spin stabilization. I'm not so sure anybody has ever seriously tested a precision smooth bore with a drag stabilized pellet. The 10M match rifles are already well beyond their shooters in terms of accuracy.

 
At February 03, 2009 12:40 AM, Anonymous wayne said...

Herb,

"I know NOTHING" as Schultz would say...
But...a top spinning with the tip in constant friction with the concrete it's tossed on, has got to be different from the air as far a effect on a tumble... at least a little.. I get the idea real well, but I'm not sure how much it transfers to the air???

Volvo,

Super congrats!!

Sounds like just the right amount of power.. Did you try JSB 8.4 at 700-800fps.. good results for me!!

Well with that great news...it's off to beddy by, for me..
You'll be up shooting all night!!!

And we will have a nice long post to read in the morning along with the Field Target Scope blog from B.B....
OH BOY!! sweet dreams tonight!!

Wayne

 
At February 03, 2009 1:36 AM, Anonymous volvo said...

Wayne,

Thanks for the well wishing.

I’m trying to play hard to get but this one is wearing me down fast. It will shoot just about everything. I did try JSB Express in it and that might be the match with the Kodiaks. The JSB’s are not the 8.4’s though since it is a .22 cal.

Some how I still naturally get tired right at last call. Ah, my misspent youth…

 
At February 03, 2009 9:25 AM, Anonymous Anonymous said...

BG Farmer, I feel you've answered your own question.
When you mention that in all likelyhood their is no such thing as a 50/100/200 mpg car because some manufacturer would have jumped on it...wouldn't the same be true of a smoothbore.
If it was more accurate, or even as accurate as a rifled bore the manufacturers would be all over it. Cheaper to make, more profitability, etc.
I consider myself to be somewhat of an armchair quantum physicist, but when I read 'A Brief History of Time'...I'm lost for much of it.
As an aside, this book is considered to be the least read 'popular' book on peoples bookshelves. So much for Hawking reducing quantum physics for the masses ;-)
CowBoyStar Dad

 
At February 03, 2009 10:29 AM, Blogger BobC said...

Herb,

I understand your points about muzzle blast and the imperfections of the pellet leading to nutation.

My question(thought) is if the barrel had well designed baffles built in, would that not stop the pressure wave from giving the pellet A "kick in the behind". It seems to me that the pellets inertia would send it down range. And the baffles? would stop the blast wave cold.

Now, if someone could design A pellet with no imperfections, perfectly round perfect skirt and smooth as glass, . . . . . . . .Does anyone make such A pellet?

BobC NJ

 
At February 03, 2009 11:10 AM, Blogger CJr said...

Bob,
I think your comment is the jist of what this pellet subject should be about. How do you make the perfect pellet by finding out what makes a pellet fly?

Different guns are obviously different in so many ways mechanical, manufacturing and power plant wise that comparison of the whys and ways pellet travel out of them is impossible. And, once you settle on the gun model you're going to use for testing that had better become a constant (and you need a good chrony to ensure that).

-Chuck

 
At February 03, 2009 12:32 PM, Anonymous BG_Farmer said...

CowboyStarDad,

I think you have conflated Herb and me.

What question did I ask? Basically, I said I've never seen a satisfyingly technical explanation of what spin does for a pellet's stability, althought there's much on how bullets are stabilized by spin. Several months ago, the question came up, and the best we could determine was that the first pellet rifles had rifled barrels based on firearms models, though perhaps "some is better than none".

Manufacturers do what sells (demand): how many competitors do you think asked for smoothbores; how many consumers would flock to buy smoothbore "rifles"? How many times have you seen a manufacturer offer a product with reduced features when compared to the former version? What manufacturer of air rifles even has an R&D team?

 
At February 03, 2009 1:36 PM, Anonymous Anonymous said...

BobC,

Re: "... if the barrel had well designed baffles built in, would that not stop the pressure wave from giving the pellet A "kick in the behind"?

Don't think so. A while back BB took the end cap off a Condor I believe, and the groups opened up. BB noted that the pressure wave can also hit the walls of the shroud and be reflected back to the pellet. Thus I think that the baffles in a shroud lessen the pressure change, and hence dampen the sound, but the pressure wave is still there. No doubt there would be a use for a "rocket scientist" here to design the best exit barrel shape and baffles within the shroud. So it seems that properly designed baffles in a shroud would help, but not completely remove the pressure wave.

After noting BB's comments about how a springer delivers its energy in the first foot, I wondered what would happen if you slit the barrel itself to dump the air pressure before the pellet left the tip of the barrel. The remaining lands/groves would hold the pellet steady. The momentum of the pellet would carry it out of the barrel, but there would be little or no pressure wave behind the pellet as it exits the barrel to disrupt the pellet flight. So you could use as much air pressure as you wanted to propel the pellet, with no increased muzzle blast as the power went up.

The pellet has a center of mass somewhere down its length. I wonder if there isn't some interaction between the center of mass, the length of the pellet, and the exit pressure of the muzzle blast that produces a shooting error. As the weight of the pellet moves forward, the pellet would seem to be more stable, to a point at least.

I shot some 0.22 Mendoza hollow points that have a solid skirt. Can't imagine that any gun shoots them the best of any pellet. My impression was that the pellets were awful because they were so tail heavy.

Herb
Armchair Guesser Extraordinaire

 
At February 03, 2009 2:06 PM, Anonymous Anonymous said...

BGfarmer...I'm not trying to ruffle anyones feathers. I just don't feel that manufacturer's such as RWS, Diana, Anschutz and such don't spend money on research.
Check here:
www.home1.fcvv.edu/~dhicketh/Math222/spring07projects/StephenCompton/SpringAirModel.pdf
22 pages of research done on linear kinetic energy and rotational velocity as pertaining to spring airguns. Lot of equations that leave me in the dust.
CowBoyStar Dad

 
At February 03, 2009 2:29 PM, Anonymous BG_Farmer said...

CowboyStarDad,

I didn't have any ruffled feathers, just don't understand how by asking a question or stating the results of a query places me in the crank conspiracy theorist category. Many months ago, I asked how and why air rifles came to have rifled barrels, even though pellets by definition are not stabilized by spin and can exhibit unwanted side-effects from it.

I've never said a smooth bore is better than a rifled one, just expressed a desire to see the actual theoretical and experimental basis for the rifling and rifling rates we have in air rifles. Until, however, we see that someone has indeed done that work, there really is a valid question, at least in my humble opinion.

Can you check the link? It doesn't seem to work for me. By the .edu suffix, I'm guessing the work is school related and not research done by an air rifle manufacturer.

Finally, I am not _repeat_ NOT saying there's a conspiracy to make pellet rifles less accurate than they could be, just wondering what we know about what we're doing. There have been, incidentally, critical rifling rate mistakes among major firearms manufacturers, for example, based on inadequate research and unfounded assumptions. One of the better examples is the .244 Rem.

 
At February 03, 2009 4:26 PM, Anonymous Herb said...

BG_Farmer

I am very sorry if I wrote something that offended you about being a "crank conspiracy theorist." Such a thing never entered my mind. I was just trying to be funny in making the point that I didn't think that manufacturers were holding back any secrets about a smooth bore gun. I forget that my warped sense of humor doesn't come across very well in e-mails, and in such comments on the internet.

I had trouble with the link too. I found the paper at:
http://home1.fvcc.edu/~dhicketh/Math222/math222projects.html


I agree that some careful research into the whole matter would be interesting. It is however difficult to design a "good" one factor at a time experimental design.

For << some >> data on smoothbore vs musket you can see:
http://www.iusb.edu/~journal/static/volumes/2000/stanage.html

However somewhat apples and oranges. Smooth bore was heavier caliber thus lower muzzle velocity I assume. I'm sure that there is other data.

Yours was not a dumb question, I gave a dumb answer. I do have fun yakking back and forth about this. I have a good science and math background, but I am no shooting expert.

Again, I'm sorry that I offended you.

Herb

 
At February 03, 2009 6:47 PM, Anonymous BG_Farmer said...

Herb,

Don't worry, I was never offended by your remarks, although I was dismayed that CowboyStarDad put me in the "200mpg carburetor club" based on our exchange:). I remain skeptical that the air rifle manufacturers have paid too much attention to a question that has more theoretical interest than practical applications, as I don't think the difference at 10M would be significant. Also, I'm not sure a perfectly smooth, round bore would be any easier to manufacture consistently than a rifled one. I notice tool marks on the lands of very accurate rifles, for example.

I enjoyed the discussion with you and would enjoy continuing it. You experiments are a good start, although experiments can be ambivalent with regards to interpretation, especially without review. That is the reason I'm happy to argue, not to put your efforts down, but to find out something.

Be very careful (as I think you are) with the musket data, as those appear to be round balls. Also, BB pointed out that military bores were loose on muzzleloaders to facilitate loading, so they were inaccurate to begin with. My guess is that rifling made the unintentional spin consistent. The math paper is not concerned with the same question we are, but thanks for the updated link; it is interesting reading.

Did you consider the rifled 760? It should be a cheap control for your 760 experiment.

Anyway, I'm no shooting expert either and my background in math and science is questionable despite a decade or so spent in the semiconductor industry:), but I will be happy to argue/discuss/experiment whenever you want.

 
At February 03, 2009 8:07 PM, Anonymous Herb said...

BG_Farmer,

I've been mulling over a Crosman 760XLS to go with the 760 I already have. However the 760XLS won't shoot like a $2000 target rifle. So I'm not sure how much one cheap barrel compared to another cheap barrel tells us anything.

Herb

 
At February 03, 2009 10:40 PM, Anonymous BG_Farmer said...

Herb,
You're probably right about the 760XLS; I was thinking the two guns might be made to similar levels of quality, but there are too many variables. I'm thinking that a precision tube in .25" from some other application might be easier to find. I don't know for certain, but it seems likely anyway. If that could be fitted to a PCP and compared to a LW quality barrel, it might yield meaningful results.

Maybe BB can put it into his R&D budget:).

CowboyStarDad,
The link you gave was an impressive model of a springer. I had been looking for one, thanks.

 
At February 04, 2009 3:28 AM, Blogger B.B. Pelletier said...

BG_Farmer and anyone else interested in the potential accuracy of a smoothbore,

You don't need to reinvent the wheel. The work was done in Ohio in the 19th century by a bunch of curious muzzleloading rifle shooters who wondered what the accuracy potential was for a round ball shot from a smoothbore.

They had a league in the 1850-1880 timeframe (I supposed interrupted by the war) where they shot round balls from smoothbores to see how tight a group they could shoot.

I discovered this several years ago when doing some research on ballistics, but I didn't hang on to the references. Nobody seemed interested. As I recall, they were able to get five-shot groups of less than five inches at 100 yards. I think there were a few two-inch groups.

Anyway, these guys did all the work for you. Now someone has to rediscover them and tell the rest of us what really happened.

Incidentally, a friend of mine has a heavy-barrel Remington smoothbore that was probably used in this research. The barrel measures about 1.5 inches across the flats.

B.B.

 
At February 04, 2009 11:31 AM, Anonymous BG_Farmer said...

BB,

That's shocking accuracy for smooth bore and round balls. I searched some for the references when you brought it up before, but didn't have much luck.

The question right now is diabolo pellets out of smooth bore. Herb believes there's an ideal rifling rate > 0, and I am questioning the purpose of the rifling at all, given the diabolo is drag stabilized. Really, I think there may be a need for rifling with pellets and an ideal rate, but I don't see any evidence that the issue has been given a lot of attention.

 
At February 04, 2009 11:49 AM, Blogger B.B. Pelletier said...

BG_Farmer,

I've sort of been following your discussion. I am of the unscientific belief that a spinning pellet IS more accurate than one that doesn't spin, but that the spin rate isn't nearly as critical as it is with a bullet.

And, agreeing somewhat with whoever thinks that not all airgun companies do their homework, up to this point the twist rate hasn't mattered that much.

B.B.

 
At February 04, 2009 2:00 PM, Anonymous BG_Farmer said...

BB,

Thanks. In my gut, I think the spin helps, too, but simply haven't seen an exhaustive explanation of the mechanism as there is with bullets (though less than I would have thought) and doubt it has been much of an issue until recently when modern springers and PCP's are pushing the effective ranges farther out. If nothing else, it could offer some insight into explaining pellet preferences.

Herb seems capable of proving not only that pellets benefit from spin, but also what rifling rates are optimal, so I am happy to see him succeed.

What can I say -- I like playing devil's advocate, although it seems like I might have to start wearing a foil hat:).

 

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