pellet resizing

For pellets, I have had the best luck with .000 (actual groove size) and nothing bigger than +.001.

Here is what may be a dumb question. Assuming the pellets are not to small for the breach, don't they get resized by the very act of the bolt forcing them into to breach? When I load a pellet into the breach in my RAW using the single shot try, as I slowly push the lever forward and watch the pellet load, it sure looks and feels like it is being resized as it goes in. I can feel when the head makes contact and then again when the skirt does. There is resistance from both. What am I missing?

I think I will try some of the Grizzly's next time I place a pellet order. Can't wait to here what our resident resizing experts have to say about this.???

30calHere is what may be a dumb question. Assuming the pellets are not to small for the breach, don't they get resized by the very act of the bolt forcing them into to breach? When I load a pellet into the breach in my RAW using the single shot try, as I slowly push the lever forward and watch the pellet load, it sure looks and feels like it is being resized as it goes in. I can feel when the head makes contact and then again when the skirt does. There is resistance from both. What am I missing?

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What is better? Different head and skirt sizes being loaded, or the exact same size head and skirt every time? I will pick the ones that are precisely the same.

It is about reducing one more variable from the equation of accuracy. Does the pellet get sized when it is loaded? Sure it does. But, why do you think the mk2's are shooting faster for you than the mk1's? They shortened the mk2's resulting in a smaller diameter skirt. The mk2's probably fit your bore better than the mk1's.

I saw a 30fps increase when I sized the hugely oversized 43gr eunjins to one of my 25 cals. The shot string tightened up as did the accuracy. No amount of sorting was going to get the results I got.

To me it is all about consistancy and taking a bunch of small details and combining them into a formula that works. Sizing is just one of those fine details.

By the way, my dies will not make a small pellet/bullet larger. If it is already smaller than the die, it will just fall thru.

In all honesty, as I have said before, sizing is great to make a pellet or bullet that is to large in diameter the correct size to fit your gun so they might shoot better. However, I would not waste my time sizing pellets like jsb's except for shooting them far. Like 100yards and further. At the longer distances, every little detail matters.

Sorry if I caused any confusion. I just assumed everyone knew I was making g pellets smaller not larger. I do believe that some pellet sizer will enlarge skirts, but surely not heads.

In regards to the Grizzly pellets, they are basically a slug not a pellet. Assuming your cricket has a choked barrel, slugs tend not to shoot very well out of a choked barrel regardless what you do to them. Most airguns need a barrel intended for bullets or slugs to shoot such projectiles well. Bullets/slugs also change alot of things.

AJ I guess what I am trying to understand is what does the sizing die do that the gun doesn't? They seem to do the same thing. Does the die remove metal? Or is it just forcing the pellet through a smaller hole? It just seems to be performing the same function the same basic way. Or is something else going on that I don't know about?

Thanks!

A high quality sizing die is running the pellet thru a perfectly round(or as close to perfect as possible)hole. This can not only get a pellet to the size you want, but also fix some imperfections of the pellet like oval shaped heads and skirts. And yes, even jsb heads and skirts can be out of round. When sizing largely oversized pellets like eunjins, lead is shaved off. Pellets like jsb's don't show anything but a smooth band around the head and skirt with light smearing and sometimes a small bit of excess lead pushed off the back of the skirt.

I will attempt to use this example to explain:
When I was building a .25 to shoot bullets, I was using the eunjins for testing so I didn't have to burn up abunch of expensive bullets. I didn't have a sizing die, but pushed pellets in the bore to "size" them and then fired them and was suprised at the gain in velosity. I had a leftover piece of barrel that I had used as the "die". Problem was that since the pellet took shape of the rifling, trying to get them loaded into the rifling was nearly impossible and the pellets shot horrible but the velocity gain was great. So, I went as far as loading a pellet, pushing it into the barrel a few inches to fully "size", then pushed them back to the loaded position so they stayed egaged in the rifling. Basically, trying to keep them timed with the lands and grooves which I couldn't do in my previous "test". This did work to some extent and accuracy was better than previous but not really any better than just shooting them out of the tin. I went as far as to drill out the piece of barrel I had used as a "die" to the groove diameter so I could see how that would work.which was better, but I didn't do a very good job on the barrel piece as I didn't have the equipment I do know and kinda butchered it. That eventually turned into the use of the Lee .250" die I still use. Initially this was about a velocity gain, since my previous uneducated test didn't provide much better accuracy. When I saw the dramatic increase in accuracy with the added velocity gain of the eunjin pellets because of the Lee die, I was sold.

Can I give you the full scientific explaination?? No, I can only tell you what I have learned and give my highly unscientific and redneck train of thought. At this point, I hadn't even really considered sizing JSB kings since they shot really well out of the tin. Knowing that some of the guys shooting long range have been sizing for a long time, led to me trying some sized jsb's. All I can say is that I didn't notice much difference at 30 yards. I moved straight to 75 then 100 yards and noticed my groups were more consistant and my average was slightly smaller. Again, small gains for the jsb's, but gains are gains at 100 yards and further non the less!!

Thanks for sharing your experience AJ. And thanks for posting the press links above. I am seriously considering trying this. Seems like it will be relatively cheap to try.

30cal, I don't think sizing is for everyone. It is tidious and very time consuming. Curiosity drives me more than anything else as it did with sizing. The simple fact that all I really do is hunt with airguns should keep me from ever doing half the tiny little steps I take for accuracy, but it is fun and learning is a good thing.

Thanks for posting your hard earned info on resizing. I agree with Ajshoots that it is not for everyone. I will stick to using a squirrel skull to resize my pellets at around 800 fps.

Dan, if you get em going up over 900fps they size alot easier!! LOL!!

make it 920!!

well I am always curious and fiddling with my rifles of all sort and I just ordered a couple dies from LEE P for the 25. Now I just need to figure out dies sizes for my 22 cricket and FX st barrel and 30 FX st barrel.

Any size suggestions???? lol

I am waiting on .218 for one of my .22's and a .300 for my .30 cal. I have been ordering exact groove size as it seems to work best thus far.

"ajshoots"I am waiting on .218 for one of my .22's and a .300 for my .30 cal. I have been ordering exact groove size as it seems to work best thus far.

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Aaron, could I suggest you try 0.217 which is 5.512 mm for .22 cal.
.218 is 5.537 mm. If you size to .218, then Yrrah roll a good sample, you may find that it has not caught all head sizes and will not do much at all for JSB .22s excepting the largest.
0.217 / 5.512 brings any head size above that down and there are not so many JSBs much less than that; and those which are 5.50 mm generally hang in with the 5.51 size.
But if your barrel has somewhat oversize grooves (indicated by your slugging test) then the .218 / 5.537 will size the skirts which may in itself somewhat reduce the "loading yaw". However I would then suggest you do some test Y-rolling to batch-discriminate the actual head sizes and make some assessment as to the results.

I can't offer much regards the 0.30 cal, as I don't have one, but have the feeling some if not all those barrels run to nearer 0.308 groove.
0.30 is 7.62 mm. 0.308 is 7.823 mm . 0.303 is 7.696 mm (essentially a British thing).
7.65 is 0.301 mm and that is what I would choose sight unseen as a catch-all for the current diabolo pellets in full length rifled barrels.

ST barrels are easy to measure and I think pellet heads should be sized to that exact size. My procedure for my ST .22 and .25 barrels is to size precisely then lightly rub the skirt on a glass plate to just allow for fractional loading thumb resistance (not felt) so the pellet won't fall out.

I should note that a loss of 10 fps, even 15 or 20 fps when pellets are sized down has not shown to be a detriment to precision shooting. The trick is to find the point at which all heads are pretty much sized to a size that allows the head to be nicely stabilized by the lands, yet keeps the skirt to, or perhaps no more than a tad above, groove size. This minimizes possible loading-yaw for those pellets that do have a head size that is less than groove size. ...
But I still stand by having a head and skirt of precisely groove size for all reasons; which in the case of pellets manufactured with heads less than a given rifle's groove size necessitates (IMO) Y-rolling after sizing to batch out the undersized heads. ... Obviously I am not writing to short range plinkers. ... Pellets with heads larger than groove size are just asking to be yaw-loaded as they are forced into the rifling before or during firing, regardless of skirt size.

A couple of relevant posts I made recently for those who don't mind reading:
http://www.network54.com/Forum/79537/thread/1442458875
http://www.network54.com/Forum/79537/thread/1444731571

Enough rambling for now, perhaps there is something here I haven't written before. .... Best regards Aaron, and all. ... Harry.

Thank you Harry!! I remember reading the linked pages when you posted them. Wonderful and educational as always!!

In regards to my choice in sizing dies. My .22 indeed has a slightly oversized bore. As you indicated, my hope is to keep all the skirts to actual groove diameter and catch any heads at or over .218. Unfortunately the jsb monster heads all tend to be under .218, but the barrel still shoots them extremely well. Hoping this helps my y roll sorting was my exact thoughts!!

My .30 is actually barreled with a TJ barrel of 1:26 twist designed specifically for the .300" jsb 44gr pellets. It is a true .300 barrel. Happens to have come from the same forging mandrel as the winner of the 2014 Extreme Benchrest.

Take care Harry!!

"Pellets with heads larger than groove size are just asking to be yaw-loaded as they are forced into the rifling before or during firing, regardless of skirt size."

Harry I think you just provided a possible answer to the question I asked. About the difference between using a sizing die and letting the breach size the pellet. Pre sizing (and of course sorting out ones that are to small) allows the pellet to load straight into the breach with out the chance of yaw loading and that's why its better. Is that the main reason?

Hey I'm chasing long range accuracy too. That's why I bought the RAW .25