by B.B. Pelletier
There’s a new video on Airgun Academy: All about lasers. Click to watch it.
Gamo Silent Stalker Whisper IGT is lightweight and looks to be a fine hunting air rifle.
If I could subtitle today’s report, it would be Making Lemonade. Because that’s what was in the box with the rifle — a real lemon of a scope! And to compound the issue, the rifle is a super drooper and the scope rings Gamo provides have no droop compensation. So, they’re unusable.
I actually tested the rifle last week and planned to report on it while I was at the Roanoke show, but the scope is so fuzzy that at 25 yards I could not see the bull clearly enough to aim. Had I been shooting at 10 yards, I wouldn’t have any problem with a fuzzy scope, because I know Gamo had to keep down their costs on this package. But this is where it really helps to have some knowledge of the product before you put combo packages together. This airgun is perfect for shooting at 25 yards, yet the scope is unusable at that distance when the power is dialed up to nine. So — you don’t put a variable scope on this gun! Package it with a 4x scope, save a little money and the shooter will never be able to see how out-of-focus it is. Maybe you could add a drooper mount from the savings, because this rifle really needs one.
Gamo also sends the scope installed in the rings, but with the scope stop pin not screwed down, where it will engage one of the scope stop holes. DUH! So I had to take the scope out of the rings to lower the stop pin. Otherwise, there ain’t no way anything other than a BKL mount is going to hold onto the scope base with clamping pressure, alone.
I stopped testing it, but I vowed to get back on the gun when I returned from the show and make it work with the products they sent in the package. I couldn’t quite do that, however, because of the terrible droop. It’s more than a foot at 25 yards; and the scope ,using all of its vertical adjustment, is still too low. I mounted a BKL 1-piece droop compensating mount that has .007 inches of droop from the back ring to the front. That mount is expensive in relation to the economy of this combo package, but it makes everything work the way it should. If Gamo had done something similar, I would have made this rifle one of Tom’s Picks; but I can’t recommend a package that needs so much after-purchase work to get it running, even if it’s a nice rifle, which this is, and even if the total price is still low.
It would be possible for owners to shim their scopes in the rear to compensate for this problem. But I took a different route with the BKL drooper mount.
My workaround
Today, I shot the rifle with the scope that came in the package. It was set at 4.5x, which was as high as it would go before the bulls started to blur. At that power, I can bisect the black bull with the reticle easily enough for precision, which is all I’m after.
RWS Hobbys
I started the sight-in with RWS Hobby pellets. The first shot at 12 feet told me it was safe to back up to 25 yards and start shooting. However, I had inadvertently selected a pellet that the Silent Stalker hates; try as I did, Hobbys were all over the place. The best they would do was on the order of three inches. I’m not going to show you a group, because the rifle did a lot better with other pellets.
JSB Exact Express
The next pellet I tried was the 14.3-grain JSB Exact Express. One of our blog readers named dg reports bad things about the quality control of the same pellet, but I didn’t find that. They wanted to go to the same place repeatedly, which is what I want in a pellet — especially one in a hunting rifle.
Before I show you the group, I have to warn you that this setup is still far from optimum. The scope works after a fashion, but a clearer scope would be an improvement.
Ten JSB Exact Express pellets went into a group that measures 1.267 inches. Don’t panic! I know that’s a big group; but if you study it, you’ll see two much smaller clusters inside. Either of them would be a stunning group of ten at 25 yards, and I think this rifle has the capability to do that.
Yes, these ten JSB Exact Express pellets made a large group at 25 yards, but notice the two tight clusters within. I think we’re on to something.
Trigger and firing behavior
At this point, I must comment that the trigger, which has a long second stage, is not very creepy. It’s a usable trigger, if you don’t have the money to upgrade right away. The firing behavior reminds me of the lower-velocity Crosman TitanGP with Nitro Piston. There’s almost no recoil if you use the artillery hold, and the rifle is actually very forgiving about how it’s held.
Crosman Premiers
The last pellet I tried was the Crosman Premier. In .22 caliber, the Premier is often among the most accurate of pellets. I thought this was going to be one of those times, but the last two shots opened a group of 1.042 inches to 1.752 inches. Those are larger numbers than I’d like for a hunting rifle, but hold your thoughts for a few minutes while I explain.
The last two shots opened this group up considerably. Ten Crosman Premiers at 25 yards.
Conclusions
The Gamo Silent Stalker shoots as well as I thought it would, but it hasn’t shown us its best yet. The poor scope they sent in the package is holding the gun back. I now have the right scope mount for the gun, so I need to find an affordable scope to really wring out everything the rifle has to offer.
I said that the rifle didn’t exhibit a lot of hold sensitivity. That’s true, but it does change points of impact if the hold is inconsistent. I need to work on that next time. Also, I twice caught myself not relaxing in the artillery hold, which throws the pellet in the direction the rifle moves when you do relax. I need to work on that. This is a very light rifle, and they’re always harder to hold steady than heavier ones.
As I said earlier, I would have no problem recommending this package as one of Tom’s Picks if the scope and mount were better. Certainly, anybody who just intends using the open sights they provide would be getting a great deal for the money; but I sense some potential and want to see what the rifle has to offer.
So, there will be a Part 4 accuracy test. After that, it’s up to you; but if you want my opinion now, I think this is a very capable spring-piston breakbarrel that has good power and stability and is perfect for hunters. The extreme light weight will be a plus on those long days in the woods.
BB – Thanks for the tip regarding my IZH46. It may be a little slow, but doesn’t seem to need a reseal yet. It’s making 400fps with 7 grain pellets, which is a good deal faster than I expected. Shooting side by side with my P17, it sounded and felt much slower, but when I ran both across the chrony, the IZH was shooting 10fps faster! Just reinforces how valuable the chrony is.
While 400fps is a little slower than spec, I’m at 2,200′ and the air is ~8% less dense vs. sea level. Should I expect a SSP to be 8% slower as well, or somewhere in between?
BTW, I ordered a copy of Yours Truly from Abe Books yesterday. The price at a few sites like Amazon and B&N was impressive!
Jay,
I noticed the same thing when comparing my 46M to my P17. I think the Izh uses its air more efficiently since it has a longer barrel. So it’s a little quieter as well as being a little faster. I live at 5500 ft and have a ProChrono so I’ll try to get some numbers for you tonight after work so we can compare. My Izh is only a couple of years old and still works like new.
/Dave
/Dave,
Your comment got caught in the spam filter. I’ve been working on it to prevent all the other spam from getting posted. In any case, I’ve whitelisted you so that won’t happen again (I hope).
Edith
Thanks, Edith. I was wondering what happened to it this morning…
/Dave
/Dave,
You probably have the 46M, while as old as Jay’s gun is, it has to be the standard 46. Huge difference in power!
B.B.
Correct – it’s the original version.
Jay,
You might try my little procedure. I made almost 500 f.p.s. in the Catskills at about the same elevation. That was shooting a gun that normally made 420 f.p.s., so the procedure does work.
B.B.
Maybe it could use a new seal – it made 400fps after trying your procedure! This one was built in 94 – I suspect it sat unused for quite a while.
Jay,
Mine is nearly as old and I have gotten it up to 470 f.p.s.. That’s not the one I shot in the Catskills, by the way. And mine does need new seals.
B.B.
Hmmm….. Maybe I need seals too… I was curious anyway, and although it’s comparing apples to oranges, my 46M at 5500 ft elevation gave me these numbers tonight. 10 shot strings. All pellets were unsorted.
(The .177 Hobbies came from 2 different tins because the ones I used in the P17 were a little looser in the 46M. The pellets from the other tin weighed the same, but were a little tighter in the 46M.)
46M:
7.0 Hobby’s
Hi-421
Lo-408
Av-415
ES-13
SD-4
2.68 ft/lbs
3.63 Joules
My P17:
Hi-376
Lo-370
Av-373
ES-6
SD-2
2.16 ft/lbs
3.93 Joules
Then, just for power comparison (I know, it doesn’t matter)-
28 year old, worn out Crosman 1322 on 15 pumps with 11.9 gr Hobby’s! (at 5500 ft I can pump my new Benjamin 397 to 12 pumps with no air left in the valve, and at 15 pumps there is no air left in the 1322…):
Hi-442
Lo432
Av-437
ES-10
SD-3
5.88 ft/lbs
6.84 Joules
You can see that the 46M has the worst extreme spread and standard deviation of all 3 pistols when it shold be the best. The P17 was almost 1/10th of the price of the 46M. (of course, the 46M has the P17 beat in everything else including accuracy! 🙂 )
/Dave
/Dave,
You got me curious so I dug into my chrony archive and found one tape roll for my 46M. I believe I shot this tape when I first got the pistol to provide a starting baseline. I didn’t write the date on it and I thought I always did. At any rate, it’s not more than a year an a half old.
10 shots, don’t know distance to first sensor but at least 15 inches.
Min – 481.65
Max – 490.27
Avg – 484.48
Ext Sprd – 8.62
Std Dev – 3.00
I shot again today 10 shots, 15 inches from first sensor:
Min – 469.76
Max – 472.61
Ext Sprd – 2.85
Std Dev – 0.00
I forgot to say I was using JSB Exact RS, 7.33gr to get these numbers.
What elevation above sea level are you, Chuck? I think I may need to reseal just based on your low ES and SD numbers as compared to mine, never mind the lower average fps. One more thing around the house that needs fixin’…. At least this one is fun though!
/Dave
/Dave,
Unfortunately, I live in Illinois, in the middle, at about 300 or so feet above the sea. Not sure if my numbers are of use to you, then? Chicago sucks so bad that it creates a very low atmospheric pressure down state which may account for my higher fps numbers.
Well, 220 feet above sea level, sample of one shot, RWS MK 8.3gr [rifle?] from a 46M gave me 438fps — probably on the high end of the curve mean.
Thanks for all the data. I’m going to shoot mine for a few weeks, then test again to see if the seals have loosened up. 400fps doesn’t bother me at 10m – I’ll be looking at the velocity spread. I missed out on the two refurbished 46Ms that PA was selling at Roanoke for $300. I did a good bit better on this one, even if I do have to reseal it.
B.B.,
For owners and potential owners of the Gamo Silent Stalker Whisper IGT scope/gun combo would bending the barrel to counter droop and re-parallaxing the scope be cheap options?
In reading reviews on the PA site there seems to be a problem with the mount that comes in the combo package so maybe potential buyers should just plan on buying a good scope mount like the BKL?
kevin
Kevin,
This rifle has a thin tube barrel liner in a plastic jacket, so I don’t know how successful barrel bending might be. Re-parallaxing the scope is of course entirely possible, but it is beyond the kind of buyer who usually buys a gun like this, so I left it out.
I do think buyers should have a plan for the mount, because the one that comes with the rifle doesn’t work.
BB, are you sure about that? Doesn’t sound like the right kind of construction for a breakbarrel…
Vince,
I just examined it again. It has a plastic jacket over a relatively thin metal tube.
B.B.
Then it looks to me like, with a fixed barrel, the barrel is joined to the receiver only once, at factory assembly time. However, with a break barrel, the barrel is re-joined to the receiver every time you cock the rifle. There’s a point of failure to be considered, don’t you think? Probably why there are those who shim break barrels. It also lends credence to Fred’s October 19, 2011, 2:42:26 PM reply about the guy who filed his barrel so it would be more flush with the receiver.
I found that article again on the Yellow Forum in the archives. Here it is:
http://www.network54.com/Forum/419052/message/1203813573/Barrel+droop+fix+by+Scottg%2C
Fred PRoNJ
BB,
I think you covered exactly my findings as well. It is interesting how your groups with the JSB Exact Express are very similar to mine. I find tight sub-groups with a larger overall group. I attributed that to a poor mount, as I mentioned before. Also, I think there is still just something about maybe the stability of the inner tube holding the reticle that is causing the sub-grouping. I’m not sure yet, as I too am trying to still refine the hold on this light gun. However, at times this thing groups dead nuts, then something changes and it gets erratic again. I hope that my new Leapers Scope, mount and trigger will make all this shine.
Can’t wait to see your update once you have a better scope.
Also, in my case the barrel is not “drooped” but actually maybe pointing “up”. Recall that I had to shim the front mount of the scope. Not sure what is going on there, but a droop compensation mount, adjusted to the opposite direction, is my solution.
DG
dg,
You can sometimes get the elevation you need just by switching ends on the mount. It may be made off-line, which is common in scope rings.
B.B.
I’ll try that. Thanks.
BB
Did you mount that BLK to the scope rail, or did you mount it directly to the receiver?
DG
dg,
I mounted to the scope rail.
B.B.
BB,
Along with the above question, as to whether mounted to rail or directly to receiver, can you tell me if the BKL-254D7 mount can be used for upward adjustment, or are these “droop” compensation mounts only adjustable from zero and down?
I was also eye balling that 260 you reviewed, but it might not be the best for elevation adjustment, I suppose.
Thanks,
DG
dg,
Just switch the BKL mount around and you get the same elevation as it gave drooped the other way.
B.B.
Is there not a concern about the direction that the cantilever is facing? Also, the BKL mounts do not have stop screws. Isn’t that a concern?
dg,
There is no concern about which way the cantilever faces. It is reversible. And the whole point of a BKL mount is that it will hold tight with clamping pressure, alone. I have tested that claim using the most severe-recoiling airguns you can find and as long as you degrease the rails before attaching the mounts, they do hold tight.
B.B.
BB, Thanks for the advice. I saw some nice reviews from you on the BKL mounts, so that might be my way to go. BTW, I called up Gamo today and walked them through my issue and explained my sight-in process. They agreed that I was doing it correctly and that I should have expected the POI to be >2″ from the POA at 15 feet. I told them that no amount of elevation adjustment, without shims, would get that sight close to that point. In fact, at center elevation adjustment the POI and POA were dead on at 15 feet. So, Gamo believes that the scope is likely bad. So, I am going to return, but I have a new Leapers on the way anyway. I purchased a 3-9×40 AO Leapers. So, I’ll get the Gamo scope returned, but will likely find the Leapers to be what I want anyway.
Also, I’ll look into a new BKL mount, like the one you are using, but I would like to remove the additional interfaces with the Gamo scope rail on the receiver, thus I think I need a medium to high rise mount to go directly to the receiver. Do you see this as necessary, if I am going there anyway?
Disappointing to hear all the issues with this set up. I had hoped maybe Gamo would have made these combos more user friendly by now.
Several years ago my nephew picked up one of the Gamo combos at a discount story and promptly brought it to me.Now mounting a scope and sighting a rifle in is no big deal, but since he was not raised with guns he found my abilities almost magical. His excitement was not containable.
Good news is the rifle was a smooth shooter right out of the box and made 11-12 ft lbs in .177. Honestly, it had a friendlier shoot cycle than an un-tuned new style HW50S which is in the same power range. Easy to cock too.
But the bad news overwhelmed the good. The two piece scope mounts included had no place being included with a springer, and the scope was also unusable. At 13 – 14 yards I could not even get it in focus. We all know the trigger was too heavy, but if used enough a shooter can adapt to a poor trigger.
But a rifle without any open sights needs a scope that works. Long story short, out of frustration he returned it after a couple weeks. When I heard the news I gave him a QB78 with a 3 x 9 x 40 leapers – which was far lower cost than the Gamo – and he was delighted with it.
Back to the sad part, how many new shooters get turned off through no fault of their own on these ill conceived set ups?
B.B., well you certainly make a vigorous case for this rifle in spite of some deficiencies. I’m wondering now just what droop is. When I think of the word, I think of gradual bending and curvature like a wilting plant. But I don’t see how a bore could curve downward in a barrel and still work. Does that mean that the bore is straight but drilled at an angle to the barrel axis? If that’s so, in cases of severe droop like this one wouldn’t you be able to see at the muzzle that the bore is not quite perpendicular to the muzzle face? And why have droop in the first place? I seem to recall that it is done with airguns to make them easier to shoot at the short ranges they are used at. Is that right?
I personally resist reading too much into sub groups of groups. Our discussion of statistics indicates that any normal testing group of 5 or 10 is already a small sample of what’s required for a “true” test of accuracy. So, looking at smaller subsets seems to me going onto the slippery slope of pattern-making. But it would be useful to identify potential that could be established with more certainty later.
PeteZ, reading in the preface to the Feynman lectures, I see that he admits that the books were generally a failure even with the “rather smart students” at Caltech(!) Those people are all highly selected. But he said that there were a few who did all the problems easily and loved the book! I wonder where they are now? Anyway, in terms of pedagogy, Feynman concluded that the class structure was a necessary evil of logistics and that the ideal format would be working one on one with a tutor. This sounds like homeschooling or the British system of university education where you do your own thing, meeting privately with tutors, and then take a make or break exam. I heard a guy who was a Rhodes scholar say that when he went to Oxford, he thought that their educational system made no sense, but in the end, he thought it was probably the best system out there.
I would tend to agree with Feynman about the tutors. As I look back on my formal schooling, I wonder what was going on in my head or that of my fellow students. The apparatus of homework and tests had little to do with real understanding. As an indirect example of the same, my previous boss had quite the resume of high G.P.A.s and honor society memberships in college and was one of the stupidest, most unimaginative people that I have ever come across. I could even say that about some professors that I’ve met. Some people have the trick of adapting very precisely to a system and gaming it without really knowing anything. However, I will say that the tutorial method requires a degree of maturity and motivation that a lot of younger people do not have, so maybe the class system has something going for it. Perhaps this is true of shooting too. Putting rounds downrange and worrying about my score and the weirdo coach and various distractions in high school didn’t do anything for me at all. It was only when it was just me and my airguns and the target that I really started learning something.
Matt61
Matt, my understanding of droop, is that the hinge of the break-barrel begins to not hold tight and true, so the barrel “droops” w.r.t. the line of sight.
As to statistics, I agree that making too much out of a small population can be a slippery slope. I work in the semiconductor industry designing metrology instruments, where statistics is pretty heavily used to determine process control and capability, so I know this area pretty well. This is why I earlier wondered if this industry had any standards in accessing accuracy, repeatability and reproducibility. To first order, I just want to know how good the guns Simple repeatability is, with no human influence, which would exclude a crappy scope or mount. Then, expand to a t-test and 3-5 operator reproducibility testing. But in the end, when “it is just me and my airgun and the target” I still don’t group as well as the reviewers as they are more skilled than me. However, after talking to Gamo, I think that I actually have a defective scope, so maybe my pride can be lifted at some point.
So it’s nice to try to reduce this to science, to at least understand the limit, so that I know which part of what I am seeing is from me, or the gun.
As to lecture styles, one-on-one had by far the most influence on me. The school system turns you into a test tacking machine. For years, after getting my PhD, I woke at night with nightmares of going into a test having not been prepared or studied. I woke with such anxiety from the years of conditioning. It’s a crazy process and I got more from the rest of the experience than what I necessarily received in the classroom.
Hi, Matt,
At root a school is a log with a student on one end and a teacher on the other. Nice to have facilities; but beyond a black/white board they’re really only needed in lab courses. Now as to what you call the “British system,” it isn’t. It is strictly the Oxford and Cambridge undergraduate system, and even then they have classes in courses where it makes sense (freshman physics for example). I speak from 4+ years as a professor in London.
The make/break exam is slowly fading from the scene, but in many of the humanities and a few of the social sciences there is still only one end-of-course grading element on which almost everything rests. But at most British universities there is now at least one paper and one exam, usually 2 papers, 2 “mid term” exams, and the final exam. There are other things I won’t bother about that complicate things quite a bit, especially in grad school.
dg___ I think every PhD has exactly the same dream. Usually I am also walking into the exam naked to make things worse.
–pz
I was going to add a comment but I really don’t think I can top this one, Pete. I do need to touch base with you again to discuss sights on the 300 and your recommendations. I’ll get back to you soon.
DG, there is also a fix complete with photos on the Yellow Forum where a machinist found that the two faces of his breakbarrel rifle were not completely flush with each other. Using some dykum blue, I think, and a file, he squared up both faces and removed his rifle’s droop. Diana/RWS rifles are notorious for drooping barrels and for this reason, BB convinced Leapers/UTG to come out with drooper mounts. They attach to the existing dovetails and are built with a slope to counter the barrel droop. What’s really nice is that they utilize a Picatinny rail system for scope mounting.
Fred PRoNJ
Matt,
Yes– the bore is drilled non-parallel to the axis of the outside of the barrel. This is common and universal with barrels. Unless you pay to have a barrel lathe turned after boring and rifling, the bore will always be non-parallel. Some barrel-making methods minimize this, like hammer forging, but it still holds true.
B.B.
BB, I thought droop was that the hinge of the break-barrel begins to not hold tight and true, so the barrel “droops” w.r.t. the line of sight. You certainly know this better than me, but wouldn’t non-parallel bores be somewhat random in distribution and equally effect windage and elevation on a random set of guns?
Matt, As to statistics, I totally agree that making too much out of a small population can be a slippery slope. I work in the semiconductor industry designing metrology instruments for process control, where statistics is pretty heavily used to gage process capability, so I know this area pretty well. This is why I earlier wondered if this industry had any standards in accessing accuracy, repeatability and reproducibility. To first order, I just want to know how good the guns Simple repeatability is, with no human influence, which would exclude a crappy scope or mount. Then, expand to t-testing with 3-5 operator reproducibility testing. But in the end, when “it is just me and my airgun and the target” I still don’t group as well as the reviewers as they are more skilled than me. However, after talking to Gamo, I think that I actually have a defective scope, so maybe my pride can be lifted at some point.
So it’s nice to try to reduce this to science, to at least understand the limit, so that I know which part of what I am seeing is from me, or the gun.
As to lecture styles, one-on-one had by far the most influence on me. The school system turns you into a test taking machine. For years, after getting my PhD, I woke at night with nightmares of going into a test having not been prepared or studied. I woke with such anxiety from the years of conditioning. It’s a crazy process and felt maybe like a vet coming back from war. I got more from the rest of the experience than what I necessarily received in the classroom.
dg,
This is why YOU need to read The Bullet’s Flight from Powder to Target. No bore is drilled straight and they all are random.
But the way they prsss in the barrels when they attach them to the base block apparently creatses the droop. It isn’t the hinge joing, because ebven rifle with locking barrels droop.
Even fixed barrel air rifles droop.
Firearms also droop, but we sight them in so far away that we never notice it.
B.B.
BB, thanks. You know there is a lot of bad information around the web, because I hear a lot of people talking about “shimming” the break-barrel locking mechanism, because of wear, hence droop. But now I understand.
Cowboy, thanks for the reference. This is just a great site of knowledge and people with the knowledge.
Hi BB,
My $.02… Barrel droop is still a sore spot with me. It’s too bad that Gamo has chosen not to address this with either a compensating mount, or fixing their manufacturing process. I can see having a little droop on a break barrel to compensate for wear on down the road, and maybe a tiny amount on a fixed barrel due to mfg tolerances. But, when I can actually see it in a picture taken full, 90 degree side-on to the rifle or pistol, I think it’s excessive (I cna’t see droop in your pic up top, so maybe you got a bad one…). My HW90 has some droop, but it’s barely noticeable unless you’re looking for it. My HW57 has even less, and it’s hard to see the droop even if you are looking for it. There are manufacturing jigs and techniques that can be used to minimize droop without adding any time or effort other than training the assemblers and welders. In my opinion, manufacturers just choose not to do this.
Down off my soap box…
/Dave
/Dave,
Several years ago I spent a half hour at the SHOT Show trying to convince the Diana VP of Marketing of this problem. She remained oblivious. So I got with Leapers and created the drooper mount for that series of guns.
However, a few years later, the Diana 350 Magnums all started arriving with zero droop. So they can fix it if they want to, but heaven forbid they should admit there was ever a problem!
B.B.
I have one of those drooper mounts. Great fix for an all too common problem! 🙂
dg, this will explain barrel droop /blog/2006/1/barrel-droop/
BB, yesterday you said, “From his book, (Donaldson) I learned a loading technique that promises to advance my accuracy with the old Ballard rifle by an order of magnitude.” I’m curious, what was it?
Mike
Mike,
Well, there is 100 times more to this technique than what I’m about to reveal, but the technique boils down to loading the bullet directly into the rifling, about a sixteenth of an inch in front of the loaded case.
B.B.
BB,
I found my scope problem tonight. I used a shoebox and cut a set of “V” grooves to make a stable rotation jig. I removed the scope and rotated it in the jig. If the optics are nice and centered the image should stay nice and stable. However, it wobbles about 2 inches 15 feet away. And the axis of wobble is in the ellevation direction. This forced the shimming and likely the poor grouping and performance.
DG
dg,
Yes, you have found a drooper.
B.B.
I think that I am going to make this my standard in-coming inspection technique for all new scopes I get.
Center up the elevation and windage adjustments, to get the optics close as possible to center range, then test for off-axis image wobble. I have a Nikon 6D Autocollimator that I might be able to get a little more fancy with, if necessary.
DG
DG,
I’m not clear on what you discovered with your scope while it was being rotated in the shoebox with V cuts.
You say “it wobbles about 2 inches 15 feet away.” Are you saying the reticles in the scope are moving? Or, Are you saying that during the course of trying to optically center your scope you’re still off 2 inches at 15 feet away on the elevation? Or?
kevin
Kevin,
From what I see, when adjusting the elevation and windage adjustments, you are actually shifting the angle of the optical axis, i.e. the image direction of the scope. The cross-hair travels with it, in the center FOV. I would assume, with a well built scope, that when the windage and elevation adjustments are at center location, so that the inner tube is centered in the main tube, i.e. everything physically centered, then, you should be able to rotate the scope 360 degrees and the image should not wobble or walk. The shoebox V-grooves simply gives a kinematic mount to insure rotation of the scope about the outer tube axis. So in this condition, the optical axis should be parallel to the physical tube axis. In my case, in this condition, I see the image wobble, on the order of 2-3 inches on an object at about 15 feet away. Not until I tighten both the windage and elevation adjustments all the way in, i.e. so that the inner tube is at the far corner of travel, do I even start to come close to a parallel optical axis to the outer tube axis.
Does this make sense?
dg,
Kudos to you for your zeroing technique. This is one of the ways BB described in a past blog entry about zeroing a scope. Great minds think alike, eh?
I’m interested in how you determined the internal sight tube was parallel with the outer scope tube. Counting clicks from extreme up to extreme down and dividing by 2 probably won’t give you a good zero, but it’ll be reasonably close, as you found out. 2″ wobble at 15′ isn’t unusual in my experience. However, having to go to the extremes as you did and still not achieve zero supports your claim of a bad scope. A really bad scope.
I hope you can send the scope back and get satisfaction.
Chuck,
To kind-of get the best gage of mechanical center, I both used the clicks in and clicks out divided by two method, but as you recognized, maybe, there are a number of clicks after disengagement that would offset that approach purely. So, I combined that with looking down the bube to spot the edge of the inner tube w.r.t. the inner wall of the outer tube. In this scope, I can easily see the edge of the inner tube, and also the engagement screws and spring. So, in the end I also used basic eyeball estimation of centering by gaging the gap around the outside of the inner tube edge.
So, those numbers turn out to be closely to 1 minute (1′) of off-axis error.
DG,
I think I’ve got it. It’s #2 in my guessing. “Wobble” threw me. Your term “walk” when you’re rotating the scope flicked the light on in my little brain.
In other words, the center of your crosshairs still rotate 2 inches at 15 yards around your POA (Point Of Aim) after significant adjustment of your windage and elevation and your result is that you’ve run out of travel for windage and elevation causing the crosshairs to be shoved to one side of the scope tube.
I’m sure the “V’s” you cut in your box are exactly parallel to one another? I used to optically center scopes using a set of scope mounts screwed onto a 2 x 4. I don’t optically center scopes anymore.
May I ask why you are optically centering your scope?
kevin
Kevin,
You got it. As to the parallelism of the V-grooves, that’s the magic of 2 narrow V-grooves. To first order, there is always a straight line between 2 points. I don’t really care if the scope is pointing a little sideways or up/down w.r.t. the box. Just that I constrain the motion to pure rotation. The two V’s cut in opposite ends of the box are each roughly knife edge V-Grooves. Make sense?
Chuck, DG and anyone else that gives a hoot,
Sorry for the delay in responding.
I think you’re “sweating the small stuff” when optically centering a scope. There are instances, like FT, when it makes sense but for hunting with airguns (which I do) or target shooting at various ranges (which I do alot) I don’t find it necessary. I’ll also add that I don’t think DG has a bad scope.
Optically centering a scope has very little to do with eliminating parallax in my experience. It has more to do with not having to adjust windage at different ranges that you shoot. After a scope is optically centered, if done correctly, your windage will be on at all ranges. You will still need to adjust for elevation. After optically centering your scope YOU MUST USE adjustable mounts since this is the only way to match the poa with poi. If you touch the windage after optically centering the scope you’ve defeated the work you’ve done.
I don’t bother with it anymore because I’m lazy and don’t find it necessary. For scoped guns I hunt with I draw an image of the inside of my scope (most of my hunting scopes have mil dots) and show poi in black dots at various ranges. Yes, the windage is off at various ranges but it’s easy to place the dot where the poi is at various ranges. I cut out this image and tape it to the inside of my rear flip up scope cap. I then have a chart to show me where to hold at various ranges for elevation AND windage. Less work than optically centering a scope and being forced to use adjustable mounts on guns that may not allow for the increased height of adjustable mounts in order to have a decent cheek weld.
For target shooting it only takes a few clicks to be on at the range I’m shooting if I shoot nearer or farther than the scope is already adjusted for.
Matching the scope and mount to the gun is most important to me. I don’t like big heavy scopes on small guns and I don’t like being forced to use mounts that compromise a repeatable cheek weld. This sometimes means I have to shim the scope and/or bend the barrel to preserve enough scope adjustment for additional ranges and make sure I’m staying away from the end of scope adjustment(s) which could result in the erector tube floating and bouncing which is deadly to accuracy at all ranges.
Now you’ve got proof at how lazy I am but in my defense I have over 40 guns with scopes and I’m constantly moving scopes from one gun to another.
kevin
Kevin, I hear what you are saying, but my scope was bad. No doubt. My earlier calculation was wrong, it turns out that my scope was out by 48 minutes. That is a sin. Even to get it within range of using elevation adjustments, I had to put 20-30 thou of shims in the front mount. That seems excessive.
Anyway, I have a new scope, went right on, did the same setup, using the exact same mounts, and no shims needed and I am just about center on my elevation adjustment. Only thing that changed was the scope.
Keven and everyone,
The Apelles boys (Ray and his father, Hans) gave up optically centering scopes many years ago. And they are both world-class field target competitors.
B.B.
Kevin,
To my way of thinking, the very center of the lens should be the better area to achieve the minimum effect of any parallax distortion. I would think, if there is a problem with the quality of a lens, it would show up most as the tube begins to look toward the edges of the lens. So, I think a scope should be as centered in the lens as possible before mounting and then use the mounts to do any corrections. Does this sound reasonable?
However, I found adjusting the mounts to be difficult and time consuming because, with the B-Square type mounts, the scope must be removed from the rings in order to make the adjustment. I think I saw mentioned on this blog some mounts where the scope stays in the rings. Those would be ideal if they’re not cost prohibitive.
Chuck, DG and anyone else that gives a hoot,
Sorry for the delay in responding.
I think you’re “sweating the small stuff” when optically centering a scope. There are instances, like FT, when it makes sense but for hunting with airguns (which I do) or target shooting at various ranges (which I do alot) I don’t find it necessary. I’ll also add that I don’t think DG has a bad scope.
Optically centering a scope has very little to do with eliminating parallax in my experience. It has more to do with not having to adjust windage at different ranges that you shoot. After a scope is optically centered, if done correctly, your windage will be on at all ranges. You will still need to adjust for elevation. After optically centering your scope YOU MUST USE adjustable mounts since this is the only way to match the poa with poi. If you touch the windage after optically centering the scope you’ve defeated the work you’ve done.
I don’t bother with it anymore because I’m lazy and don’t find it necessary. For scoped guns I hunt with I draw an image of the inside of my scope (most of my hunting scopes have mil dots) and show poi in black dots at various ranges. Yes, the windage is off at various ranges but it’s easy to place the dot where the poi is at various ranges. I cut out this image and tape it to the inside of my rear flip up scope cap. I then have a chart to show me where to hold at various ranges for elevation AND windage. Less work than optically centering a scope and being forced to use adjustable mounts on guns that may not allow for the increased height of adjustable mounts in order to have a decent cheek weld.
For target shooting it only takes a few clicks to be on at the range I’m shooting if I shoot nearer or farther than the scope is already adjusted for.
Matching the scope and mount to the gun is most important to me. I don’t like big heavy scopes on small guns and I don’t like being forced to use mounts that compromise a repeatable cheek weld. This sometimes means I have to shim the scope and/or bend the barrel to preserve enough scope adjustment for additional ranges and make sure I’m staying away from the end of scope adjustment(s) which could result in the erector tube floating and bouncing which is deadly to accuracy at all ranges.
Now you’ve got proof at how lazy I am but in my defense I have over 40 guns with scopes and I’m constantly moving scopes from one gun to another.
kevin
Just what exactly are you trying to do anyway?
When I get a new rifle I check it for droop if I can get a small level on both the body and barrel. The short “torpedo” levels work most of the time.
With some of an idea if it is going to droop (and which way) I may or may not decide on drooper mounts or ordinary “no droop” mounts to start with.
Next I center the scope by rolling it like you did, but with it looking at a target 20 yds or better away. Adjustments are made until very little variation in crosshair movement is visible.
Next, mount the scope and see where it shoots at 20-25 yds. This is going to tell me if the POI is going to be so far away from the POA that there might be trouble with adjusting the scope for zero. Knowing if you can expect trouble is going to go a long way in the right direction to keep you from running in circles trying to get a rifle to shoot right.
twotalon
twotalon,
You got it. I do exactly like you. But in my case this was the way that I figured out that I had a bad scope. I was not able to get the cross-hair, i.e. the optical axis, parallel to the scope axis with the windage and elevation adjustments. It got close at the most extreme adjustments, but still off. So this is how i figured the scope was bad.
http://www.rr.com/news/topic/article/rr/9000/53780033/Sheriff_Exotic_animal_farm_owner_killed_self
About an hour south of me – crazy stuff
That is just insane…. I guess the farmer won’t have to answer for it….
/Dave
Looks like shooting fish in a barrel.
http://www.webn.com/cc-common/news/sections/newsarticle.html?feed=119585&article=9274247
That is the epitome of a tragedy.
/Dave,
By now you’ve more than likely seen the news, but just in case–the farmer committed suicide after he opened the cages.
Bruce
Yeah, I read that part, Bruce. So, I guess in a sense, he’s already answered….
/Dave
BB,
Tonight I think I tamed the wild beast. I received my new scope, and it went on great. It’s the Leapers 3-9×40. No need to shim, the scope was true. But that was only the tip of the iceberg.
I started with what I originally thought was my best pellet, so far, the RWS Superdomes. The groups were OK and allowed me to center at 18 yards, but I was still not impressed with the groups of still 2 inches. But I had also bought some new pellets to go with the new scope purchase. H&N FTT and Diablo Exact Jumbo Heavy.
After some lack-luster performance with the Superdomes, I put in the H&N FTT. At first I was almost afraid to use it because they went in soo tight I was almost afraid of it getting stuck. They are by far the tightest fitting. However, I could immediately tell somethiing magical was happening. I changed targets to get a fresh setup of targets with the H&N FTT and shot, in a row, 5 seperate 5 shot groups each the size of a dime, basically just one big hole. And the kicker is tha’s in 15-20 mph wind gusts. It was night and day to what I have been able to do so far. My gun REALLY likes the H&N FTT. The Diablo Jumbo Heavy were nearly as good, but a few strays out to quarter size. I can shoot dime sized groups with the H&N all day long. You should try them on your list.
I feel like I’m one of the gang now, able to make some good groupings. Who ever said that each gun has their prefered type was 10000% correct. I am ready to move out to 30 yards now this weekend.
DG
DG,
I hope I have some of those pellets in .22. I t sounds like you have found what it takes. At this point you can stop searching and only occasionally try other pellets to see whether these are still the fairest in the land.
B.B.
BB, I hope can try them out also. In general, the trend seems to directly follow that accuracy is following the BC values. I’m interested in going further up the list…(the following list is sorted in order of BC values, for 0.22 cal only).
The first half of the list is what I have (have tried, with exception to the Crosman Premier still coming).
The point is, as I go up in BC I tend to get a direct correlation to grouping. The RWS Hypermax and Beeman Silver Arrow don’t even hit the target, i.e. many inches off. It gets progressively better, until my latest, with the H&N FTT. So, it seems to make some sense, I guess.
Cal Name BC Grains
0.22 RWS Hypermax 0.01 9.9
0.22 Beeman Silver Arrow 0.012 17.1
0.22 Gamo Match 0.014 13.9
0.22 RWS Superdome 0.016 14.5
0.22 Crosman Premier 0.019 14.3
0.22 Predator Polymag 0.026 16
0.22 JSB Exact Jumbo Express 0.027 14.3
0.22 JSB Jumbo Exact Heavy 0.027 18.1
0.22 H+N FTT 0.029 14.8
This second group is even higher BC, so I am very interested in giving the Beeman Kodiak a try.
0.22 JSB – Daystate FT 0.029 16
0.22 AA Field 0.031 15.9
0.22 JSB Exact 0.031 15.9
0.22 Eley Magnum 0.032 30
0.22 Exterminator 20.5 0.032 20.5
0.22 Bisley Magnum 0.035 21
0.22 RWS Eun Jin 0.035 27.8
0.22 Beeman Kodiak 0.036 21.1
Shouldn’t I expect this type of trending, and expect even further improvements as I go up in BC, or is this just wishful thinking?
DG
DG,
Ballistic coefficient isn’t what makes a pellet accurate. But you can’t know which ones to use without trying them all, and if there seems to be a correlation in your gun, that’s the way to go. And I think you will be surprised that the Premier has a good BC despite its lighter weight.
B.B.
Yea. That’s why I actually chose the H&N and the Exact Heavy. They both had high BC/weight ratios in the higher BC class.
I’m stuck on the H&N FTT for now, but will follow your advice and sample from here, but will likely continue to test the trending as I stretch out my range.
DG
BB, actually, I just took my database of 61 0.22 cal pellets with BC and weight, and sorted it with a BC/weight ratio. The H&N FTT is #1 as the highest BC/weight in the whole list. The Beeman Kodiak are #9 and the Crosman Premiers are #25, and again the Silver Arrows and Hypermax are in the bottom. However, my top three, so far (H&N FTT, Jumbo Exact Heavy and Predator Polymag) are in the top 20, pretty much in order.
Maybe I’m trying to make too much sense out of the numbers and looking for trends that may not hold exactly true, but only for rough scaling. I’m going to give the Crosman Premiers a go, and I need to retest the Jumbo Express, even though my experience in quality left me a little cautious with these.
DG
BB,
I tried those Crosman Premiers today. I’m out to 30 yards now. The Premiers are nice, but still not as good as the H&N FTT. They look, feel, and almost fit like the H&N. I got quarter to 1 – 1.25 inch groups with the Crosman Premier, but I can still get dime groups with the H&N FTT at 30 yards. It’s just amazing.
Another interesting note, I don’t have a Chrono, but I extrapolated muzzle velocities from the few numbers you gave in Report #1 and estimated that the H&N FTT would exit at roughly 669 ft/sec. I had already run the trajectory path for the H&N FTT for it’s BC, weight and this extrapolated velocity. I went to 40 yds with the H&N. Got a 1.25 to 1.5 inch group, but the center of the group was 1.25 inch bellow the bull. This exactly matches my trajectory calculation for centering up at 30 yds, so I figure the 669 ft/sec might be about right.
I’m loving these H&N’s. Good luck.
DG
DG,
Because you actually took the time to test all that you did and you extrapolated the probable velocity for H&N FTT pellets, I’m going to order some if I can’t find them in my pellets on hand and I will test them for you.
I will see how close your extrapolation comes, plus I’ll see how well they group.
B.B.
BB, Thanks. I am confident you will like them.
DG
DG,
You’re doing some good shooting, there. Did you get the Crosman Premiers in the cardboard box or the round tin? According to this blog, the ones in the box are more accurate than those in the tin. I have always used the ones in the box so I can’t personally back up that claim but I’ve heard it enough times on this blog to believe it must be true.
Keep searching for the better pellet. I’ve been through 18 types so far and found some excellent versions but I still think there’s one out there that’s better. Unfortunately, there are an infinite number of the dang things being made. PyramydAir sells at least half of those 🙂 and therein lies my dilemma.
Chuck,
Thanks. I was not sure if my abilities were out to lunch or if it was the gun, until I found these magic beans. As to the Crosman Premiers, I got them in the tin, from Pyramid. Thanks for the tip on the box. Where do you buy them and how do you order them to distinguish between box or tin?
Same place you got the tin… Pyramyd (two ‘y’s). The illustration typically shows the box vs a tin, though the pellet count may also be a good sign (>600 pellets per box large calibers, >1000 for .177)
/brands/crosman?mid=30 (try to ignore the AirSoft balls and regular BBs)
Wulfraed, Thanks. I’ll check them out. Why two ‘y’s in pyramyd? Just curious about the choice of spelling from the company.
Chuck, I have noticed that the tins of Premiers have a wide range of fit in the barrel. Some are tight, some are loose. Maybe the boxed versions are held to a tighter tolerance???
DG
Responding to the second query…
The claim is that the boxes are, at the least, all from a single lot/forming session. The tins, OTOH, are populated from multiple lines/lots — you might get a tin that has over 90% from one machine, or a tin that looks like someone “swept up” the overflow from filling boxes and jumbled them together.
Think of it them as “blended” vs a “single malt” whisk(e)y.
Hi, Mr. B. B. Pelletier great blog. I’ve read this article on “Gamo’s Silent Stalker Whisper IGT air rifle” and now I understand what I’ve rode on a different web page about the same problem ( I was interested). I really appreciate all this info as well a suggestion, because I want to buy my own rifle and It was hard to save my money for it, so I want a good one. I’m interested only in a .177 caliber (“capable of kill an elephant at 100 yards”) seriously I would like somethig for extreme benchrest and small game and I like Gamo, Thank you so much in advance for your suggestion(s).
Futural,
Okay, it’s time to be honest. No Gamo spring rifle will ever be able to compete in “extreme benchrest.” You might be able to use a Gamo PCP, but even then, it’s a stretch.
So, what do you mean by “extreme benchrest”?
To me, that term means shooting groups beyond 100 yards with a smallbore air rifle. And I would hope to see ten-shot groups of one inch or smaller. Five-shot groups are no test for accuracy, and anything closer than 100 yards isn’t extreme.
Now, you want to hunt small game with a .177? Then you do need very good accuracy. You should limit your shots to the distance at which you can hold all of them inside 3/4-inch. That is like being able to hit a nickel with every shot. So whatever distance you can do that at, that is your maximum hunting distance. I say that because the .177 pellet isn’t a good killer. Being so small, it can slip past vital areas in game and pass through without stopping the animal. A .22 pellet, in contrast, is enough larger that it increases the chance of contacting the vital areas by a lot. The groups can be enlarged to one inch if you shoot a .22.
The Silent Stalker Whisper is a breakbarrel, which is the most difficult rifle of all to master. Your hold has to be perfect with a spring-powered breakbarrel. The groups shown above are from 25 yards, but they are the same size that you would get from a PCP at 60 yards. So, plan on learning how to employ the artillery hold if you get a breakbarrel springer. It will make you a better shot in the long run, but it is very difficult to learn.
I don’t have any suggestions if you have to stick with Gamo guns, only. They are all about the same accuracy, and what you see here is typical. Only the underlever CF-X is appreciably better.
But if you want a more accurate breakbarrel, I would suggest the RWS Diana 34. It is more inherently accurate than the Gamo, plus it has a much better trigger. However, it is still a breakbarrel springer and will be very difficult to shoot accurately.
B.B.
Thank you, so much for your info It helps a lot to make me an informed buyer. I got your point.
When I wrote extreme benchrest I mean waht you describe but now I know I was wrong (with the caliber that I want, I like to learn.) my intention is pest control and benchrest of 50 or 60 yards I think this a more realistick approach.
I know that I have to work hard on the artillery hold in order to improve accuracy, now I’m open mind to hear suggestions about the brand and model, It has not to be Gamo but something that I really want is .177 It could be gas ram or spring-powered.
I was checking Pyramid store and Iliked the RWS Diana 34 as well the RWS Diana 350 magnum in combo to make a start in airguns, I thought It’s good value for the price, what do you think?
Futural,
I thought about recommending the 350 Magnum, but decided not to because I think the powerplant is really too much for .177 caliber. A lot of potential power is wasted when you get that rifle in .177.
The 34, however, is much better-suited to .177, though it is also good in .22.
I think you might be ready to get a gun now. My advice is to buy one without a scope and try that out for a while. Get used to shooting with open sights before you scope the rifle.
When the time comes to buy a scope, we can talk about which one then.
Try Crosman Premier pellets in the brown cardboard box. Get the ones that weigh 7.9 grains — not 10.5 grains.
And also get a tin of JSB Exact RS and a Tin of Air Arms Falcons.
B.B.
Thank you so much, again for your time and info. Now I’ll get something suitable to my needs and wallet I’ll buy the Diana and try all those pellets and see…