GTA
All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: nervoustrigger on February 07, 2013, 12:31:59 AM
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Updated Aug 14, 2013: .22 caliber updates:
- CPHP
- H&N FTT 5.53mm
- JSB 13.4gr
- JSB 15.9gr
- Predator Polymag
- RWS SHP
These new entries are highlighted in yellow so they're easy to spot.
As with their .177 counterparts, it looks like JSB and H&N have the more consistent head sizes in the group.
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Updated Aug 12, 2013: new copy attached with several pellets added, mostly in .177 caliber. For new entries, now including the standard deviation which, along with the extreme spread, gives a good sense of how consistent the pellets are from a given tin.
As before, standouts are highlighted green for good and red for bad.
If you are interested in compiling your own data, there's a calculator below the main table where you can enter in up to 20 measurements and it will summarize the average, extreme spread, etc. which you can then add to the table.
Also has a simple fpe calculator and a couple of additional sheets, one for plotting a PCP shot string and another with my little table of Sun Optics adjustable scope rings.
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Old post:
Good evening guys.
I just wanted to share a copy of my pellet log. Some high points:
1. head sizes: typical, min, and max head sizes
2. calibers represented: mostly 22 cal and a few 177 cal
3. rifles tested in: accuracy comments for each one...I only have 4 rifles but I know some of you guys have the same models
4. vendor info: vendor and purchase date to give you a sense of how fresh the data is, and thus whether you can reasonably expect to get something similar if you were to buy a tin today.
If you have a rifle that is picky about head size, I am hoping you may find it useful. Comments and criticism welcome.
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Thanks for taking the time to contribute this info.
Hopefully it helps some one out, when looking for a pellet for a certain gun.
Very cool of you.
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Thanks!
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Downloaded! Thank you very much for this awesome, helpful info. It's nice to have resources like this on hand for quick reference.
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NICE! This information is great.
Did you save yards-to-target and group size information? I'm just wondering what "crazy accurate" is, haha.
I'll be doing some testing with my XS25, once I get access to a chrony, so I'll use this same spreadsheet layout.
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Good info.
It would be interesting to see the bore size of each of the guns as compared to the head size of the pellets. For instance, my Crosman 1377 carbine has a slightly larger barrel than my Walther Force 1000 break-barrel. My Crosman loves JSB Exacts, Hevies, and Monsters. The Walther prefers Beeman Crow Magnums.
The bore size can be measured with gauge pins (carefully) or by pushing a lead pellet through the bore and measuring the smallest diameter with calipers.
Did you measure the pellets with a caliper or a micrometer?
JMJ
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Great info!!
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I have the muzzle diameters for my rifles so I'll see about analyzing that tonight. Thanks for the suggestion. As for measurement method, please see the notes below the table.
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As for measurement method, please see the notes below the table.
Sorry - missed that. Thanks - JMJ
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I'm just wondering what "crazy accurate" is, haha.
Yeah, not exactly an SI unit of measure, is it?
Crazy accurate I consider to be 3/8" CTC 5-shot group at 25 yards with the B51 and Predator Polymags. And no fliers that I can attribute to anything but me.
And I'm no marksman, I don't care what it says over there under my handle.
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And a 3/4" 7-shot group with the B51 and JSB 15.9 at 45 yards. To me, that's crazy because I could never dream of such while shooting springers and gas rams...even once on a good day. Those who can have my utmost admiration and respect. Oh, and jealousy. This I can shoot any time, in fact this one was after 4 hours of hard yard work when my muscles were tired and twitchy.
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That's awesome. I'll be honest: I want to learn to shoot my springer well, but the siren-call of PCPs is steadily growing stronger...
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Okay, here's a new copy that begins to explore the relationship between the pellet head size and muzzle diameter.
Firstly, note I'm distinguishing the muzzle here because I don't have the tools to reliably measure the bore diameter. My assumption is if there is a difference between them, the muzzle will be the smaller of the two. However, I tend to think there is little to no choke on any of my three (3) .22cal barrels based on the muzzles measuring 0.2155" to 0.2160". The Beeman RS2 is the only one that I can noninvasively access the breech and it measures the same on each end.
I was thinking the B51 was choked based on its stellar accuracy but I guess not.
My only .177 cal, the lowly Daisy 880, measures 0.178 or maybe even 0.179 (hard to tell) so that may explain why I've had such a hard time finding a pellet it likes. Until seeing this, I figured it was equal doses of several imperfections. After all, what can I expect from a $40 air rifle? But now I'm tempted to put some choke on it and see what happens. Anybody have some DIY pointers? I have a hammer and a mean streak ;D
Anyway, on with the analysis...
So what's new?
Have a look at the red circled areas in the screenshot attached. Here's what's been added:
1. spread calculation - Difference in max and min head diameters in the tin. Those with a spread of >0.003" (0.076mm) or greater are highlighted red.
2. pellet to rifle correlation - this is a group of 3 new columns titled:
a. shoots well in / shoots poorly in [this rifle...]
b. whose muzzle is sized
c. for a difference of (with respect to the pellet)
How do I read it?
Since there are many pellets that are sort of ho-hum, mediocre, or inconclusive, what I did was focus on those at the extremes. The very good and the very bad.
The good combinations are highlighted bright green. The poor combinations are highlighted bright pink.
What does it mean?
Well, I humbly submit what I think it says. Snug-fitting pellets do not ensure good accuracy but undersized pellets pretty well guarantee poor accuracy. Kinda like the old saying about horse racing, the win doesn't always go to the swift. But that's the way to bet.
Lastly, the hall of shame
Check out the spread on the Gamo Match wadcutters. 9 thou. or 0.23mm! These were a gift from my sister-in-law. How could she know? How could anyone know they could be that bad? And yes, they are absolutely abysmal at grouping. Flyers the likes of which I have never seen before.
Hey, it's the thought that counts.
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Excellent! Significant amount of time invested there - I appreciate your efforts. FPE calculator at the bottom is a very nice touch! 8)
It's a nice bonus that your work provides a great template for anyone else who wants to assemble the information for the guns and ammo they have.
Very well done Sir! :)
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Really appreciate this work! I think (and hope) that this and a few other recent pellet to gun comparison threads are going to get a larger ball rolling. Maybe there's a way to generate a top 5 pellet listing for various rifles, even if the data is coming from different sources. It's a whole extra layer of serious to wrap around this awesome hobby.
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Thanks for the kind words, Briar. That's been the highlight of my day so far!
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Hey guys, in case anyone is interested, I made a few updates to the spreadsheet and posted a new copy in the first post.
Take care,
Jason
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Great job! Thanks for sharing.
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OK, Maybe it's just me. But through heresay and actual testing, I have an Idea which pellets are most accurate.
It seems that the ones that I would guess to be the most accurate are all either the correct size or larger.
The undersize ones are the least accurate.
In .22 I have seen that CPHP and JWS-Jumbo shoot well for me and RWS superdome does not.
My rifle like the larger pellet?
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Super duper wild and WOW, Jason. Many thanks!
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Hey, thanks Stefan and Chaffyn! I really appreciate your kind words.
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It seems that the ones that I would guess to be the most accurate are all either the correct size or larger.
The undersize ones are the least accurate.
So far, it has been my experience that what you say is true...that a pellet rifle will tend to be more accurate with pellets whose heads are either the same size or just slightly larger than the barrel. That helps ensure the pellet stays engaged to the rifling so it can achieve the proper spin stabilization. And the pellet will tend to emerge from the muzzle as nearly perfectly parallel as possible.
Conversely, it's easy to understand why undersized pellets don't fare so well. Logically, if you think about the expanding gas pushing the pellet from behind, an undersized head pinballs back and forth against the rifling as it accelerates toward the muzzle. So it doesn't stay engaged with the rifling and therefore does not spin up properly. Also, the pinballing behavior means that just as the pellet emerges from the muzzle, it will be slightly tipped in some random direction each time, throwing it off course.
But with that said, every once in a while it seems there is a pellet and barrel combination which defies logic. Since the previous posting, I found that my Beeman RS2 springer prefers slightly undersized JSB 10.3gr pellets. Slugging the barrel I got 0.177" across the riflings, whereas the pellets are measuring 0.1755". So the pellets are a full 1-1/2 thousandths smaller than the barrel, yet they somehow shoot more accurately than anything else I've tried. Not just 10 or 20 yards but out to 45 yards. I wish I had an explanation for it but I don't.
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been a while since i've been on the blog. What did you use to measure the headsize? i'd think i micrometer would work but only gives one diameter (for instance would not show if a pellet is slightly oval-shaped) I've seen the setup ted (ted's holdover) uses just curious to see how you were getting your measurements.
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It seems that the ones that I would guess to be the most accurate are all either the correct size or larger.
The undersize ones are the least accurate.
So far, it has been my experience that what you say is true...that a pellet rifle will tend to be more accurate with pellets whose heads are either the same size or just slightly larger than the barrel. That helps ensure the pellet stays engaged to the rifling so it can achieve the proper spin stabilization. And the pellet will tend to emerge from the muzzle as nearly perfectly parallel as possible.
Conversely, it's easy to understand why undersized pellets don't fare so well. Logically, if you think about the expanding gas pushing the pellet from behind, an undersized head pinballs back and forth against the rifling as it accelerates toward the muzzle. So it doesn't stay engaged with the rifling and therefore does not spin up properly. Also, the pinballing behavior means that just as the pellet emerges from the muzzle, it will be slightly tipped in some random direction each time, throwing it off course.
But with that said, every once in a while it seems there is a pellet and barrel combination which defies logic. Since the previous posting, I found that my Beeman RS2 springer prefers slightly undersized JSB 10.3gr pellets. Slugging the barrel I got 0.177" across the riflings, whereas the pellets are measuring 0.1755". So the pellets are a full 1-1/2 thousandths smaller than the barrel, yet they somehow shoot more accurately than anything else I've tried. Not just 10 or 20 yards but out to 45 yards. I wish I had an explanation for it but I don't.
That is fascinating. I have no idea why that would happen unless somehow the barrel tightened a little and then in the last half inch or so it expanded again because it wouldn't stand to reason that it would shoot a smaller pellet better. I had also wondered about creating a device that would pre size pellets. Think of it as a choked push through barrel (unrifled). So if you had a .1770 barrel which preferred .1772 pellets you could push all pellets through the pre barrel giving hopefully giving them a consistent size. (any pellets two small would simply fall through i guess) just spit-balling ideas. would be neat to see if something like that could work.
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thanks for sharing. I found it interesting that the crossman measured out at 5.51 while the jsb's were smaller and the JSB's seem to have a better reputation.
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Thanks! I've been hoping to see all this in one place... you've saved a lot of people a lot of homework.
8)
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been a while since i've been on the blog. What did you use to measure the headsize? i'd think i micrometer would work but only gives one diameter (for instance would not show if a pellet is slightly oval-shaped) I've seen the setup ted (ted's holdover) uses just curious to see how you were getting your measurements.
I'm using calipers checked against NIST gauge pins of the same nominal diameter as the pellets I'm measuring. I could probably interpolate in 0.0002" increments but I'm limiting it to a half-thousandth (0.0005"). I wish I had a nice micrometer to get finer resolution but I'm finding that there is enough difference between different makes and types of pellets that the resolution I have is adequate to discern some meaningful differences.
I don't evaluate roundness, per se, but I take 2 measurements from each pellet approximately 90deg out from each other. In that way the extreme spread tends to open up if the pellets are out of round by very much.
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thanks for sharing. I found it interesting that the crossman measured out at 5.51 while the jsb's were smaller and the JSB's seem to have a better reputation.
It's a little early to say but now that I'm tracking standard deviation, it looks like JSB (and H&N, who is also held in pretty high esteem) holds an edge over brands like Crosman and RWS. And indeed, my experiences with JSB and H&N had been that they yielded more consistent groups day in and day out than other brands in general. That is, provided the rifle "liked" one of them to begin with. My first two rifles hated JSB pellets and then my next two just loved them. Nowadays I cherish the QB79 for its affinity for cheap Crosmans because a steady diet of JSB weighs heavy on the wallet.
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First time reading this thread. Thank you for the write-up and chart and that is some fantastic shooting Jason.
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but I'm limiting it to a half-thousandth (0.0005").
Okay. One more WOW headed your direction. You're the main guy today!!!
I'm still trying to keep my new shooting bench from wobbling back and forth
a few inches with each shot. Forget 0.0005". I'll get there. Just wait.
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thanks for sharing. I found it interesting that the crossman measured out at 5.51 while the jsb's were smaller and the JSB's seem to have a better reputation.
It's a little early to say but now that I'm tracking standard deviation, it looks like JSB (and H&N, who is also held in pretty high esteem) holds an edge over brands like Crosman and RWS. And indeed, my experiences with JSB and H&N had been that they yielded more consistent groups day in and day out than other brands in general. That is, provided the rifle "liked" one of them to begin with. My first two rifles hated JSB pellets and then my next two just loved them. Nowadays I cherish the QB79 for its affinity for cheap Crosmans because a steady diet of JSB weighs heavy on the wallet.
Yes exactly.
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Just made some 0.22 cal updates. See original post for a summary and downloads.