Monday, November 23, 2009

The Benjamin Katana - Part 2

by B.B. Pelletier

Part 1


Benjamin Katana.


Well! There has been a lot of emotion over this latest PCP release from Crosman. The first report of the Benjamin Katana attracted more comments than a normal Friday, plus we lit up the Yellow Forum, as well. They say no publicity is bad publicity, so we'll see how things turn out.

But underneath all the gossip, there's a real air rifle to be evaluated. Forgetting all the trash that surrounds it, how does the Katana perform on its own merits? We will start looking at that today, as we delve into the issue of velocity and energy potential. Since the rifle is available in .22 caliber only, the job is somewhat simplified.

The barrel IS choked
I confirmed the choked barrel with Ed Schultz, Crosman's production manager and head engineer. So, this rifle should deliver stunning accuracy. For those who are not aware, there's a simple test that can often confirm whether a barrel is choked or not. Simply push a pellet all the way through the barrel with a cleaning rod. If you start at the breech and the barrel is choked, you will feel some slight resistance about two inches from the muzzle. If you start from the muzzle, as the Katana requires because its bolt is not readily removable, the resistance is at the start of the push and becomes easier after the initial few inches. Checking from the muzzle is harder to do and takes an experienced hand, which is why I wasn't 100 percent certain about the choke in part 1.

Why no shroud?
Several of you asked why there is no shroud around the barrel. The answer lies with the Discovery receiver upon which the Katana is based. It is lower than the Marauder receiver, which means the Katana barrel has to be closer to the receiver. There isn't enough room between the receiver and barrel for a decent-sized shroud to fit.

On to velocity
The first test will measure the potential total shot string. After that, I'll know where the power band is in relation to the fill pressure. This isn't exact, because as you change pellets the power curve expands and contracts. As a rule of thumb for a non-regulated system like the Katana's, though, heavier pellets will get a couple more shots in the zone than lighter ones, probably because they hold the valve open longer. But I'll check that, too.

Crosman Premiers
A little bird named Paul Capello told me the Katana loves Crosman Premier pellets. Paul is also testing the Katana and finds the Premiers very accurate in his test gun. When I say Crosman Premiers, I mean the ones in the brown cardboard box, not the ones you can buy in tins. The "Premiers" in tins are not sorted by the die they were made on, but I think the boxed Premiers still are, so the pellet-to-pellet variation should be less.

I filled to exactly 2,000 psi on my carbon fiber tank gauge, which seemed to agree very well with the gauge on the rifle. I'll show you the entire shot string now, and then interpret what I think it means.

SHOT/Velocity
1 / 776
2 / 776
3 / 807
4 / 806
5 / 810
6 / 818
7 / 814
8 / 815
9 / 815
10 / 819*
11 / 808
12 / 815
13 / 814
14 / 817
15 / 811
16 / 807
17 / 809
18 / 806
19 / 804
20 / 801
21 / 793
22 / 789
23 / 784
24 / 772

* Fastest shot

Well, this is a good velocity curve. I see 20 good shots that are within 30 f.p.s. of each other. That would be shots 3 through 22. If I wanted to keep them all within 20 f.p.s., then I'd stop after shot 20, which gives a total of 18 good shots. The average for that spread would be 811 f.p.s. (rounded up), which works out to a muzzle energy of 20.89 foot-pounds.

The indicated reservoir pressure after shot 21 was 1,200 psi. Keep that in mind as I move to a heavier pellet.


Indicated air pressure after shot 21.


Beeman Kodiaks
It has been difficult to buy Beeman Kodiak pellets for many months, but now that Pyramyd Air distributes the entire line of H&N Pellets, you can substitute with H&N Baracudas, which are the same pellet. I checked and Baracudas were out of stock as of this writing, but Pyramyd Air will have a standing order for them, and they should always be available in the future. I have a few Kodiaks remaining and will continue to use them until they're gone.

Kodiaks gave an average velocity of 681 f.p.s. for 10 shots. I had filled to just shy of 2,000 psi to shave off those first two slower shots seen in the first string. It worked, too, because here are the numbers for this string.

SHOT/Velocity
1 / 678
2 / 681
3 / 682
4 / 681
5 / 686
6 / 687
7 / 674
8 / 687
9 / 677
10 / 677

So Kodiaks generated 21.63 foot-pounds of muzzle energy, on average. That's about the same as a tuned .22-caliber Beeman R1.

Gamo TS-22
Next, I decided to test a new pellet--the Gamo TS-22 Long Distance pellet. This is a .22-grain domed pellet that resembles an H&N Baracuda more than a little. I'll be trying them in the accuracy test, so I thought we should get some velocity data, as well.

I did not refill the reservoir after testing the Kodiaks, so, given my 18-shot spread that I mentioned in the Premier test, I shot only eight pellets for velocity in this test. That way the total number of shots on this fill would be 18, and you could see if my initial assessment of usable shots held up.

The average for eight shots was 669 f.p.s., for an average energy of 21.87 foot-pounds. So you can see how they went, I will give you all the velocities now.

SHOT/Velocity
1 / 674
2 / 667
3 / 673
4 / 671
5 / 663
6 / 674
7 / 668
8 / 664

That was the string that generated the average I gave you. As you can see, it varied by only 11 f.p.s. However, I continued to fire to see what the next few shots would do.

9 / 658
10 / 654
11 / 655
12 / 653
13 / 653
14 / 648
15 / 646
16 / 643

Shot 16 is also the 26th shot fired on this fill. That includes the 10 Kodiaks I shot previously. As you can see, heavier pellets give more shots at a closer velocity, because the final 16 shots in the fill varied by only 31 f.p.s. Since the first 10 Kodiaks varied by only 13 f.p.s., I think it's safe to interpolate across the two different but similar pellet types and assume that heavier pellets give longer shots strings with the Katana. At the end of all this testing (both Kodiaks and Gamo TS-022s), the pressure gauge on the rifle registered 900 psi.

Other things noted during the test
I noticed that the trigger has a definite first and second stage. The second stage is not a crisp break the way it is adjusted right now. I can feel it pull through a long but creepless pull before letoff. I will do a separate report on adjusting the trigger, because there's a lot to it and I want to do it justice.

The bolt handle is about a half-inch too short for comfort. With this fatter stock, the handle should stick out a little more to give you something to grab hold of when cocking the rifle.


Bolt handle is too short. It needs another half-inch.


That's it to this point. The Katana is very consistent at just over 20 foot-pounds of energy. And 18-26 good shots are possible with every fill.

55 Comments:

At November 23, 2009 8:46 AM, OpenID CrimsonSky said...

The Katana is Plenty accurate. Perhaps the BEST .22 cal5 shot group I've ever achieved while bench rested was with this rifle. I'm no marksman, so this is quite impressive. Here is a photo of a group, right out of the box...no cleaning, no fussing. This was my second attempt with the Premier Brown Box:

http://www.airgunreporter.com/misc/katana-group.jpg

 
At November 23, 2009 9:03 AM, Anonymous Anonymous said...

Speaking of H&N pellets:

I'm looking forward to two pellet offerings that Paul Capello mentioned in his "Overview video of H&N Pellets", that I have yet to see in PyramydAir's product lineup as of yet. The Baracuda Hunters (round-nose hollowpoint) and the Rabbit Magnums should be exciting.

Just when I think I have spent enought money on everything I need to buy for this hobby, the thought of new pellet offerings keeps my wallet open.

 
At November 23, 2009 9:33 AM, Anonymous Anonymous said...

I am just wondering if the three new rifles from Crosman are really that different. Are the internals the same of different.

 
At November 23, 2009 10:00 AM, Blogger B.B. Pelletier said...

What do you mean by "the internals"? The firing valve? The hammer? The hammer spring? The trigger? The reservoir tube? The air inlet valve?

Just like General Motors made two different cars called the Camaro and the Firebird that contained a large number of the same parts, it makes good economic sense for a company to use the same parts on different items. But just because the parts are the same doesn't mean that the products turn out the same.

No, all three of these rifles are very different from one another. For example, the Discovery doesn't have a choked barrel or an adjustable trigger. The Katana isn't a repeater, nor it it quiet.

This report will show what the Katana is like, just as the reports on the Discovery and the Marauder have shown what they are like.

B.B.

 
At November 23, 2009 10:23 AM, Blogger FRED said...

I'm about to fix the problem with the Discovery not having an adjustable trigger. I've ordered a kit from one of the on-line vendors (TKO - Mike T) and I'm hopeful that over the Thanksgiving Weekend, I'll be able to report on the results.

Fred

 
At November 23, 2009 10:27 AM, Anonymous Anonymous said...

What is the status on Crossman coming out with a PCP Pistol? Is it going to be available soon, and will it be available in .22? Any info anyone can share will be appreciated.
-Jeff (marauder Owner)

 
At November 23, 2009 10:36 AM, Blogger B.B. Pelletier said...

Jeff,

I've been expecting to see it out before Christmas, but there are a lot of details to resolve at the final moments before a product launches. Certainly it will be displayed at the 2010 SHOT Show in January.

B.B.

 
At November 23, 2009 10:42 AM, Anonymous Anonymous said...

Will a TKO suppressor/silencer work on the Katana?

I like the idea of a quiet PCP, or at least, as quiet as a springer.

G.

 
At November 23, 2009 10:47 AM, Blogger FRED said...

Mr. B,

I had not completely read all the comments on the Nov. 17th blog so did not see that you, too, ordered the TKO trigger mod. Well, if you get it installed, let me know how you like it. I'm kind of committed since I ordered it last week, Friday.

Fred

 
At November 23, 2009 10:51 AM, Blogger FRED said...

Anonymous G,

suggest you go to the website www.tko22.com and send Mike T. an e-mail or call him. He'll have an idea if his breaks fit a Katana and remember, you owe it to yourself to do a search on this Blog about barrel modifiers or suppressors and learn how this country at least, looks on them. BB wrote a very strongly worded article on this type of device.

Fred

 
At November 23, 2009 11:04 AM, Anonymous Anonymous said...

Fred, will do.

BTW. I've read everything BB says about suppressors. My understanding is that the suppressor must not be capable of being converted or used on a firearm.

I'll report back with Mike's response.

G.

 
At November 23, 2009 11:36 AM, Blogger kevin said...

CrimsonSky,

You're not a marksman? I think you play one on TV and I've seen some pretty good shots that you've made.

Anyone,

Are the Gamo TS-22 pellets the same as kodiak's/barracuda's?

B.B.,

Hope crosman is listening. The bolt handle length seems an obvious and necessary fix.

kevin

 
At November 23, 2009 11:39 AM, Blogger B.B. Pelletier said...

Kevin,

I think the whole airgun world is listening to and reading everything about the Katana. It seems to have captured everyones' attention.

B.B.

 
At November 23, 2009 11:49 AM, Blogger kevin said...

B.B.,

You are absolutely correct. The buzz after your last article was frenzied and your article couldn't have been up for 30 minutes this morning without a link being attached to the crosman AND yellow forum.

How does it feel to never be allowed to leave the stage/limelight?

kevin

 
At November 23, 2009 11:54 AM, Anonymous Anonymous said...

Off topic

I'm in the market for a new scope and have been looking a two: Centerpoint's 3-12x44AO compact and Leapers 3-12x44AO mini. am I reading correctly the Centerpoint to be 1/2 the weight and $60 more?

I know weight has nothing to do with price. better glass and knobs maybe???

Regarding the Katana; looks like a reasonable gap fill. I'd rather see a Marauder carbine though.

dsw

 
At November 23, 2009 12:08 PM, Blogger B.B. Pelletier said...

Kevin,

Sometimes I get tired of it. I can't just have an opinion anymore, because someone is waiting to turn it into THE TRUTH. Like I have better judgement or know any more than anyone else.

But I guess it also means that people are reading what I write and thinking about it. So I just have to be a better me, who doesn't make many mistakes.

Thank God for Edith!

B.B.

 
At November 23, 2009 12:10 PM, Blogger B.B. Pelletier said...

Scopes,

Let me look into this for you. I think the weight is in error somewhere. Or these two are vastly different.

Edith?

B.B.

 
At November 23, 2009 12:23 PM, Anonymous Anonymous said...

Tom, not looking to cause any problems, was just wondering if the firing system was the same, trigger can be different etc just wondered about the valve etc,,,,like the rifles but can't test all of them as you can..

 
At November 23, 2009 12:30 PM, Blogger woguph said...

BB,
You mentioned that the reason the Katana doesn't have a shrouded barrel is that the action sits too low in the stock. It seems that a breech spacer would raise the action and a shrouded barrel would bring the barrel up to where the stock would fit better. Guys have been adding the spacers to the Discovery to give the spacing for a shrouded barrel. Maybe someone will get a Katana and buy a spacer and see if a Marauder barrel will then fit.

David Enoch

 
At November 23, 2009 12:32 PM, Blogger CJr said...

Good report, BB! Every time I read about your shot strings I learn more and more about my own equipment. Though I must be pretty dense. How much can one learn from just a string of numbers? Yet, today, I looked at your Katana shot strings and a light turned on and I went, Oh yeah, I get it now!
-Chuck

 
At November 23, 2009 1:07 PM, Blogger B.B. Pelletier said...

David,

I'm sure you are right about what guys will do with the Katana. Maybe it will turn out so well that Crosman will wish they had made the gun that way to begin with. I know they watch this part of the market to see what people will do and what they want.

B.B.

 
At November 23, 2009 1:10 PM, Anonymous Anonymous said...

B.B.

That choked barrel, if it is as good as a Lothar Walther, is certainly an important feature. I take it that the Lothar Walther is not choked.

I'm continuing to exult in the surprise break. Why didn't you tell me about it before?! Heh heh, just kidding. Maybe it was better to find out by experimentation and comparison with other methods rather than slavishly imitating something I didn't understand.

BG_Farmer, you're right that the huge credibility of Nancy Tompkins is the missing piece of the puzzle regarding wind values. By all means, update your groups. I'll be using the time to refine my surprise break. >:-)

Matt61

 
At November 23, 2009 1:15 PM, Blogger B.B. Pelletier said...

Chuck,

Each of us has gone through the same experience. Once you get it, you start to understand about valve timing and backpressure and the length of the barrel affecting pneumatic velocity.

B.B.

 
At November 23, 2009 1:18 PM, Blogger B.B. Pelletier said...

Matt,

Lothar Walther will sell their barrels both ways--choked and unchoked. If you ask them, they will tell you that the choked barrel will be more accurate.

This is why it is often unwise to cut a barrel on a pneumatic, as it could be removing the choke.

B.B.

 
At November 23, 2009 1:32 PM, Blogger B.B. Pelletier said...

Regarding the Katana powerplant parts, there is a difference because the Katana doesn't have the air transfer port limiter that the Marauder does. And with the Marauder being able to use pressure from 2,000 to 3,000 as well as CO2, I would guess the valve is somewhat different, too, but I don't know that.
I have not been inside this Katana to look at the powerplant parts.

B.B.

 
At November 23, 2009 1:35 PM, Anonymous Mr B. said...

Fred,

You know I almost reposted the 17 Nov reply. Trigger kit hasn't arrived yet. Will let you know or you'll let me know how they work.

Anonymous G,

The Katana barrel and bolt sure look like the Discovery's. If Mike T's Stage 5 muzzle break fits the Katana you sure won't be disappointed in how it works. It's great on my Discovery. I'm using the 7.5" one.

Wogump,

I've seen riser breeches for sale, but no breech spacers. Would you please point me in the direction of one. Thank you muchly.

Mr B.

 
At November 23, 2009 1:37 PM, Anonymous Anonymous said...

I contacted Mike from TKO about a suppressor for the Katana, here's his response:

"Yes, the TKO Stage V muzzle brake will work with the Katana." Mike T.

I also asked about the legal context of his suppressors, he said:

"Our muzzle brakes are designed for use on low powered co2 and PCP airguns. Any other use would be dangerous to the user and bystanders. A plastic soda bottle can be easily converted for use as a suppressor on a firearm. Not until the act is actually accomplished is the soda bottle now a NFA firearm." Mike T.

So there you have it.

G.

 
At November 23, 2009 1:39 PM, Blogger CJr said...

I forgot to tell you all that I took second place in the AirgunArena 10m rifle bench rest eMatch competition this month. I'm awaiting my prize which I think is a PA gift certificate.

My Mr.T shooting CPs got beat out by an Anschutz 8001 shooting Vogels (?!). The score was 233 to 218 out of a possible 250. He beat me by 15 points :D LOL and all that. I had a lot of 10s but also touching the 9 ring, so 9 was the resulting score.

I didn't think my score was that great but I wanted to participate and support the matches anyway and see what a little pressure would do to me (nothing like Wayne's experience of course).

I'd encourage all of you to register and shoot there (except there goes my chance of ever winning anything again :))

-Chuck

 
At November 23, 2009 1:39 PM, Anonymous Anonymous said...

Mike responded to my question:

"Yes, the TKO Stage V muzzle brake will work with the Katana." Mike T.

So there you have it.

How much noise does the muzzle break remove... is it as quiet as a springer? or quieter?

 
At November 23, 2009 1:42 PM, Anonymous Anonymous said...

BB,

I didn't even think of a typo on the scopes info! lol! I googled centerpoint and looked up the scope to find the two I am comparing are of similar weight.

any info you can share, or anyone else for that matter is appretiated. is the Centerpoint worth the extra $60 over the Leapers? and what differences, if any, are there?

thanks.

dsw

 
At November 23, 2009 1:47 PM, Blogger B.B. Pelletier said...

dsw,

Thank you for pointing this out. Centerpoint's site apparently has hosed-up specs that were copied. Edith is working with them now to get clarification.

B.B.

 
At November 23, 2009 1:52 PM, Anonymous Anonymous said...

dsw,

I've contacted CenterPoint Optics and asked several questions about their product. First off, the weight of 17.7 oz. may be way off. According to the owner's manual for that scope, it weighs 7.7 oz. The manual also states it has 1/4 MOA, but another place in the manual tells you how to adjust 1/8 MOA.

As soon as I hear back from them, I'll post the info here & correct Pyramyd Air's product specs that need editing. I hope the CP people aren't off from work this whole week.

Both scopes come with a sunshade & flip-open lens covers. All other specs are identical between the Leapers & CP scope.

Edith

 
At November 23, 2009 1:53 PM, Anonymous Anonymous said...

One tiny correction...Except for those items noted, all other specs appear to be identical between the Leapers & CP scope.

Edith

 
At November 23, 2009 2:09 PM, Blogger FRED said...

Cjr. - excellent shooting. Now WW can't share all the glory and I'm sure, is happy to have some of the pressure removed from his shoulders :).

Mr. B, I'll report on the trigger group ASAP - this will take priority over fixing my 10 yr old plus leaf blower (it's either the priming pump diaphragm or the crank seals. And I thought I'd never be inside another two-stroke engine again).

 
At November 23, 2009 2:11 PM, Anonymous Jane Hansen said...

I'd just like to reflect a bit on our wind deflection thoughts. While I agree that the basic equations of motion suggest our shooter Nancy Tompkins is in error, the empirical evidence is in her favor, (ie - she shoots very well). Our observations bear her out, and we constantly research our ability to predict such things.

You'll notice I rarely resort to explaining things using equations.
Two reasons, first, it's hard to know when to apply them, (most people will agree with our "f=ma" argument as our pellet enters the breeze wind, but refuse to do so as it passes the fan. However, relative effects are real, and when that bullet passes the fan, it sure feels like it's getting pummelled from wind "particles" from the opposite side.

The second is that these formulae are simplistic in nature and simply aren't good enough to predict ballistics in fluids, (they do OK in a vacuum).
Even our "basic" projectile equations are more than can be run on a desk-top PC. Worse, as we understand the complexities of fluid dynamics, we've uncovered things like "Lagrangian coherent structures", which are invisible, but real, barriers in chaotic fluids that govern the movements of not only small particles, but also of aircraft in flight.

Long before we resort to complex equations, we need to be able to envision these phenomena in thought experiments that help us grasp the concepts, (and can generally tell us what will happen, but not "quantify" it).

best regards,

Jane

 
At November 23, 2009 3:36 PM, Blogger BG_Farmer said...

BB,
Your approach to Katana is the right one -- take it for what it is. No more guff from me about the shroud:).

Matt,
I don't know whether I'll get better groups or not -- it would seem almost impossible not to, but I keep tinkering:). I'm in a no-surprise mode for triggers, especially offhand, but working on a fast steady pull, somewhere on the good side of a jerk:)!

My boy and I set up a coffee can at 75 then 100 yards yesterday, and I was hitting it pretty easily offhand with the old 36-2, and the "groups" were just three or four inches at 75 yards with pointed pellets, until I started trying, at which point I had a hard time hitting the darn thing at all:).

Jane,
It is a good thing you jumped in on Tomkins side!

 
At November 23, 2009 3:49 PM, Blogger Vince said...

Yes, BB, some DO hang on your every word. I still remember the cheapie-springer writeup you did a while back on, I think, the TF49, in which you mentioned that the gun you tested had power comparable to the R7. Needless to say, stories started flying around that the TF49 was an R7 clone...

 
At November 23, 2009 4:06 PM, Anonymous Anonymous said...

Jane,

I, for one, am glad that you are not unleashing all of your equations, and I'm certainly in favor of the conceptual explanation.

You're right about the vast complications and the credibility of Nancy Tompkins. Certainly, the basic kinematic equations are not going to tell the whole story. However, against the universe of complications, I would like to oppose (an admittedly incomplete) vision of coherence among the various scientific explanations.

To be expansive, quantum physics gets into the super nitty gritty details that are glossed over by Newtonian physics of which F = ma is one part. And quantum physics has some results that are completely different like the tunneling phenomenon. BUT, on the same scale as Newtonian physics, quantum mechanics reduces to the same results. The same at the other end of the scale with relativity. It has unintuitive results but reduced to the same value scale as classical physics, the results are the same.

Closer to home, we know that the flight of a projectile is not really the parabola predicted by basic kinematics. But the effects of wind resistance, so far as I know, just squish and reshape the parabola. They don't turn it into something wildly different like a sine curve. So, the reason I don't completely throw out the basic kinematics result is that if there were some countervailing force at work, I would think that it would either appear in the basic equations or that it would appear much more prominently in the study of mechanics. Moreover, the result of kinematics suggests that the muzzle wind is 18 times more effective than the downrange wind which is a lot to overcome. I'm reminded of B.B.'s point that even a slight misalignment between front and rear sight will have a much greater effect than a misalignment of the correct sight picture on the target. What goes on at the muzzle is powerful stuff.

But there's no reason to close the door on Nancy Tompkins either. Her information on wind boils, mirages, fishtails, safe-siding shots and so on radiates authority and is more extensive than Tubb's. Maybe something critical happens between 600 yards which is Tubb's main distance and 1000 yards where she operates. Anyway, I can add to the complications myself. My cousin who is a retired astrophysicist said that you cannot assume the acceleration on a projectile produced by the wind will be the same for different distances since the different velocities of the projectile have an effect on air friction--admittedly small.

Matt61

 
At November 23, 2009 4:09 PM, Anonymous Mr B. said...

Anonymous,

I don't think that anonymous G has a TKO brake--yet. I do and it is quieter than any of my springers, but don't forget most of the springer's noise comes from the "twang" of the power plant while a PCP's or CO2 gun's noise come from the gas exiting the muzzle.

I just tried a very unscientific comparison and to my ear my Stage 5 Brake is a smige quiter than a Beeman P17. The real quetion is, how quiet do you want and how much do you want to spend?

It's like drag racing. It doen't cost alot to go from the fourteens to the thirteens, but that .20 from 6.0 to 5.8 can cost a whole lot.

Hope that helps you out.

Mr B.

 
At November 23, 2009 4:31 PM, Anonymous Mr B. said...

CJr,

Congrads on your 2nd place. Look out Wayne here he comes!

I was shooting the SS the other day and thought about you. Have you ever forgotten to take the safety off and wondered why Mr T didn't go off when you felt it should have?

Try shooting with the safety on and see where the cross hairs are when the trigger finally stops moving.

Did they move off your bullseye at any time? Did they stay dead on through out that long long trigger press? For me that little exercise has given me a marked improvement in my shooting.

Let me know if it works for you.

Mr B.

 
At November 23, 2009 4:54 PM, Anonymous Anonymous said...

Thanks Mr. B.

That gives me a good noise comparison. My goal is not to disrupt the neighbors when I shoot. The pop from the gun should be no louder than the impact of a soda can. A Crosman 1377 multi-pump is about as loud as I'd like the rifle to get. It sounds like the TKO break will do the job.

I'm interesting is stepping into PCP but noise and hand pumping are controlling my urge to buy. As I see it a 2000 psi gun is ideal for hand pumping (please comment) and a TKO break will tame the noise.

G.

 
At November 23, 2009 5:33 PM, Anonymous Mr B. said...

G,

How many pumps do you want me to put in my Crosman 1377 for the comparison?

I'm also shooting a Talon SS equipped with an AirHog shroud on both air and CO2. It's a chore to get from 2000 to 3000 PSI. I'm 66 with 40 years of smoking (stopped five years ago) and it'll give me a little bit of a work out.

The HPA pumps come with a base that is too small. It won't allow me to get my feet a shoulder width apart making pumping a real pain. Made a proper sized base and cut the effort in half. The only way to fly.

I mostly plink in the yard on CO2 and hunt with air.

The impact of the pellet hitting a grackle at 16-20 yards makes more noise than the gun firing on either air or CO2.

Mr B.

 
At November 23, 2009 5:50 PM, Anonymous Jane Hansen said...

Matt:

I agree, to a degree - I'v become much more comfortable throwing out my old conclusions and equations in the face of valid evidence, and keep searching until I find a new theory that explains the observations.

So much has changed that my "advanced" education is all but useless. We had no idea of Lagrangian structures, dynamical chaos, hell, we still can't explain the Coanda effect. One thing we know is that 20th century physics has let us down...


A note to G:
On PCPs, take the dive. The hand pumping won't get you down. I own two, and both use air faster than the Crossman offerings, and I got used to it fast. My AA takes less than 80pumps to refill, and that is no time at all... (My Korean hunting rifles DOES burn through air, but I only use it for hunting, so no problem).

regards,

Jane

 
At November 23, 2009 6:22 PM, Blogger BG_Farmer said...

Matt (&Jane),

I don't see any problem using simple mechanics to get a "usable" answer (when v is much less than c, at least!), but only if you are sure you have all the major forces involved mapped out.

Why not model the path of the ball in Jane's original superfan thought experiment calculating the speed and direction of the ball from initial velocity, wind and drag (lateral and frontal) at small intervals of t and see what happens? Assume the ball is perfectly spherical, the air is uniformly dense, the coefficient is constant, etc. -- you can even ignore gravity and give the ball a flat trajectory. Sounds like a high school physics problem.

 
At November 23, 2009 8:16 PM, Anonymous Anonymous said...

Edith,
thanks. I'm gonnna have ta find one of those CP's up close in person before I buy. Have several Leapers and this one looks like the same stuff.

Matt & Jane,

whew! does me good to see smart people that also hunt! :)

dsw

 
At November 23, 2009 8:51 PM, Blogger FRED said...

My apologies to Matt, Jane and Herb for what I'm about to say. When you folks start talking about pellet trajectories, decaying flight paths, deflections plus Magnus effects, my eyes start to glaze over and I'm brought back to my Quantitative Analysis Class in college. The one that I was totally lost in. Microwaves and oscillating dipoles also was a bit of a problem for me. But with all the formulas being tossed back and forth, I was wondering why no integration or differential equations to try to model the behavior and decay of the flight path of a pellet.

Now I know. You three were having mercy on me and the rest of us reading this! Thank you.

Fred

 
At November 23, 2009 9:12 PM, Anonymous Anonymous said...

Mr B & Jane

Thanks for your comments. I shoot an RWS 350 springer in 177 and like the flat trajectory, accuracy, and 21ft/lbs it generates. I don't like the weight, vibration, and lack of swivel studs.

I'm thinking of a PCP sometime next year and keenly watch BB's posts about the Crosman PCP line up.

I want a mixture of hunting power with plinking thrown in for practice and trigger time. Now the sound problem is solved I'm more open to the idea of a PCP.

PS. 1377 on 10 pumps doesn't seem to bother my neighbors. Soda can or backboard impact is about as loud.

G.

 
At November 23, 2009 9:22 PM, Anonymous Mr B. said...

G.,

I'd say that it sounds like the 1377 at maybe 2.5 pumps.

Mr B.

 
At November 23, 2009 9:54 PM, Blogger CJr said...

Mr B,
I have forgotten that @#$%%^ safety many many times. I'll get settled on the bench, get the target in sight, take a deep breath, let 1/4 of the breath out, slide the sight up to the bull, squeeze the trigger and squish! Nothing! Exhale with a blast of wind, the @#$%^ safety is still on @#$%^.

I will try your "dry fire" technique. Sounds interesting.

Wayne has nothing to fear from me. I'm a long way off from his flight. However it would be interesting to see his scores on eMatch. Wayne? You Game? 10m, .177, any rifle, bench rest, any sight.

-Chuck

 
At November 23, 2009 10:01 PM, Blogger CJr said...

Mr B,
I just thought of something else. I'm using the lowest possible setting on Mr T to get the most shots. Now I wonder if this is a good idea. Maybe I'd get those x's more often if I upped the ante? What do you think? What setting are you using?

-Chuck

 
At November 23, 2009 10:15 PM, Blogger ajvenom said...

CS - nice shooting, the only .22 AR that I own that shoots that well at 20 yards is my daisy .22 SG. My Disco .22 hits about 8mm ctc at 20 yards or so. I do have a .177 barrel for it, but haven't had the time to use it much.

My Disco does shoot better then my springer which hits about 12mm ctc on average at 20 yards. So I've been pretty happy with my Disco so far.

If I had to pick one mod for the Disco, it would be a power mod to lowe the pwoer and increase the shot count. IMO....All PCPs should have this feature. I nice trigger doesn;t hurt either.

 
At November 23, 2009 11:04 PM, Anonymous Mr B. said...

CJr,

I've got the power wheel on 5 That's on CO2 at about 70 degs. For some reason it'll shoot to the same POI on air at 2700 PSI. Doesn't make any sense to me either. Although I haven't shot both in a couple of weeks. We'll check it tomorrow and let you know.

Mr B.

 
At November 23, 2009 11:21 PM, Blogger DB said...

Have to agree with ajvenom. The Disco power mod is so easy it is a no brainer. Likewise the three screw trigger mod is so easy...

Learning to adjust the three screws can take time. That is assuming your a hack like me. But once you dial it in it workd very well enough.

Personally I like to also mod the trigger link. That eliminated the creep and the sear drag on the hammer which can cause power fluctuations.

 
At November 23, 2009 11:49 PM, Blogger Grantland said...

Jane Hansen said...
"... hell, we still can't explain the Coanda effect."

On this point, Jane, I'm building a silencer for my Talon ss, and I'm using cones instead of baffles. I figure that not only the "front" of each cone will hold back the onrushing air, but that the air directly behind the pellet, as it penetrates the conetip hole, will be pulled to the sides by Coanda effect, thus reducing the immediate fast air in a direct vector with the pellet. One trouble is I figure the laminar flow will only "stick" to the inner cone surface at a very low angle - ie a loong pointy cone OR I'll have to start narrow and curve wide, like a bell. You reckon I'mm wasting my time, given the fluid velocities?

(I don't much like math, sorry,- hope I was intelligible :)

 
At November 24, 2009 10:09 PM, Anonymous Anonymous said...

Does anyone know if the Katana stock will fit the Disco? What about the barrel?

 

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