First off, all credit to this fun little experiment goes to Motorhead, as he shared the idea a few years ago. Scott, having machining abilities, made his own dies.
Can a .22 pellet be sized down to a .20? YEP.
Since Scott shared this I've been intrigued by the idea. For various reasons:
This is how it came about, and the prelim results from yesterday.
I'd considered, and almost bought a couple graduations of NOE sizers a couple different times, knowing that I'd have to open at least one of them up to .20. Was dissuaded by going that route b/c they are straight-walled and would not preserve the head to skirt ratio that seems to be important to pellets. Could have flared them I suppose, but that'd be yet another step.
Reached out to a machinist and didn't want to pay for his time. Not that I don't appreciate the skills a machinist possesses, just wasn't willing to pay that hourly rate for an experiment with potentially zero utility.
A month or two ago was talking to Ben that puts on the Xtreme FT matches here in AZ and he mentioned the TR Robb sizer that he has in .25. And how it has a continual taper through the sizing die portion. An idea came to mind....could a .22 and a .20 sizer be used to get .22s down to .20 in two steps? Asked Ben what he thought and he said perhaps, if a guy took the stop out completely on the .22. (Ben was 100% right by the way).
Asked here on AGN if anybody knew how small the .22 would go. Biohazardman was very helpful in telling me his would get them down to 5.48, with the stop in place, which is a little under 0.216.
https://www.airgunnation.com/topic/tr-robb-sizer-in-22/?referrer=1
Decided to go for it and ordered the TR Robb sizers in .22 and .20. Took a few weeks but they arrived day before yesterday. Working nights and the whole shift I was itching to get home and try them out yesterday morning.
First step was to removed the stop on the .22. Two bolts and it comes right off. Tapped a .22 all the way through with a rubber mallet, using the pusher it came with. Pellet was TOUGH to get through, and came out with a thoroughly mangled, nearly ripped off skirt. Well, that's not gonna work. Close inspection showed that the tip of the pusher it came with was too blunt, and the skirt was being pushed between the walls of the sizer and the shaft of the pusher, ripping it. Two options at that point, modify the pusher, or "make" my own. Issued pusher is a bit short for pushing pellets all the way through the sizer so found an old phillips screwdriver with a mangled tip, and cut off the "phillips" part. 3 minutes with the belt sander (yeah, you machinists are cringing) and I was in business, flat tip with a steep enough angled cone to keep the shaft area of the pusher safely behind the skirt in the die.
Measured those best I could with a caliper and head size was about 0.210. Tested a couple in the .20 sizer, and after a few adjustments could get them to a pretty consistent head size of 0.2 and skirt of 0.206. My comparison .20 factory were coming out of a tin of JSB 15.89s. The factory .20s were measuring 0.2 on the head, and .209-.210 on the skirt. So, the die has a bit steep taper than the factory .20s, at least from that one tin.
I'm able to push them through both steps of the sizing with just the screwdriver and hand pressure, no rubber mallet necessary.
Chambered one and it went in like butter, just as smooth as a factory .20.
The results...
(was pushing them a bit too hard into the stop and giving them a small flat, almost a meplat, was able to mostly do away with that on the second batch).
.
Also tried some of the 21 grain H&Ns...but no accuracy test with these
Texted some airgun buddies in my excitement and then couldn't get some targets out fast enough. Threw a target down at my guess of 50, 75 and 90 yards. (I got kinda close).
Test bed was the .20 Taipan Veteran (gun details here: https://www.airgunnation.com/topic/veteran-short-20/?referrer=1)
Started with hammer tension at the same place that produces 910fps with the 15.89gr JSBs for about 29fpe. Best guess is that they were throwing the sized down 18.1s between 830 and 860).
First 5 shots @ 46 yards
First 5 shots @ 71 yards (with 1mil elevation added to the turret)
And then about 15 @ 92 yards (top three up in the orange were the last three, FAR below reg pressure so fps was up so they hit higher).
I felt like they were maybe "chambering" a bit too easy and was curious if a slightly bigger head would improve accuracy. So, quick adjustment of the .20 stop and I could get them to a head size of 0.201-0.203 with a skirt of about 0.209-211. Still chamber very easily, with just a touch of resistance, about like chambering an OEM JSB pellet.
Also decided to up the power and bit and get out the chrono. Went one half revolution "in" on the hammer tension to get to here (5 shot average at the muzzle).
So about 31-32fpe.
At that point figured I might as well try to capture a BC too....
This is a 5 shot average @ 45 yards.
Might vary with the calculator used, but I'm getting a BC of 0.042 with the one that I utilized. That's better than I've ever captured from the 18.1s as .22s (BC of 0.035).
So, accuracy with the slightly larger head and increase in power.....
5 @ 46 (the new holes, compare to previous 46 yard target)
5@71 yards (new holes again)
and about 25 shots @ 92 yards (entirely new paper here)
The upper right hole was my guess at turret elevation, took it down some after that first high shot. From there I didn't do any adjustments for wind or anything else, just held on the middle of the orange. The holes off to the right are where the wind was pushing them as it was a bit gusty. But the bulk of them in that main cluster are a pretty good representation of what it can do.
All shots taken from horribly uncomfortable prone position (breaks my neck every time). I could shrink them with less caffeine and more sleep in my system, and from a bench, and holding off for wind.
Overall better results than I was afraid of. I think the factory .20 (15.89 Heavies) are slightly more accurate and gave a little better measured BC, but there's potential here that I'll investigate further in the future. I'd like to accuracy test some of those 21 grain .22 H&Ns and maybe even some of the 19.6grain cast pellets from the .22 NOE pellet mold I bought a few years.
So, it can be done, with perhaps not stellar/excellent accuracy, but at least decent accuracy.
Pretty happy with the TR Robb sizers. Only using calipers to measure but results seem to be pretty repeatable and it's a pretty quick process, even with the two stage size reduction. They can't increase the size of course, but I'm curious to see if the .22 sizer could be used somehow to homogenize some of my lower quality batches of .22 Monster RDs that seem to be so exceptional at long range, but have a flyer or two every so often.
I've so far had a lot of fun with this and just wanted to share.
Can a .22 pellet be sized down to a .20? YEP.
Since Scott shared this I've been intrigued by the idea. For various reasons:
- In case pellet manufacturers ever put the stop on production of .20s, (as the .20 naysayers often naysay)
- What kind of BC and long range accuracy would a heavy .20 have?
- General curiousity
This is how it came about, and the prelim results from yesterday.
I'd considered, and almost bought a couple graduations of NOE sizers a couple different times, knowing that I'd have to open at least one of them up to .20. Was dissuaded by going that route b/c they are straight-walled and would not preserve the head to skirt ratio that seems to be important to pellets. Could have flared them I suppose, but that'd be yet another step.
Reached out to a machinist and didn't want to pay for his time. Not that I don't appreciate the skills a machinist possesses, just wasn't willing to pay that hourly rate for an experiment with potentially zero utility.
A month or two ago was talking to Ben that puts on the Xtreme FT matches here in AZ and he mentioned the TR Robb sizer that he has in .25. And how it has a continual taper through the sizing die portion. An idea came to mind....could a .22 and a .20 sizer be used to get .22s down to .20 in two steps? Asked Ben what he thought and he said perhaps, if a guy took the stop out completely on the .22. (Ben was 100% right by the way).
Asked here on AGN if anybody knew how small the .22 would go. Biohazardman was very helpful in telling me his would get them down to 5.48, with the stop in place, which is a little under 0.216.
https://www.airgunnation.com/topic/tr-robb-sizer-in-22/?referrer=1
Decided to go for it and ordered the TR Robb sizers in .22 and .20. Took a few weeks but they arrived day before yesterday. Working nights and the whole shift I was itching to get home and try them out yesterday morning.
First step was to removed the stop on the .22. Two bolts and it comes right off. Tapped a .22 all the way through with a rubber mallet, using the pusher it came with. Pellet was TOUGH to get through, and came out with a thoroughly mangled, nearly ripped off skirt. Well, that's not gonna work. Close inspection showed that the tip of the pusher it came with was too blunt, and the skirt was being pushed between the walls of the sizer and the shaft of the pusher, ripping it. Two options at that point, modify the pusher, or "make" my own. Issued pusher is a bit short for pushing pellets all the way through the sizer so found an old phillips screwdriver with a mangled tip, and cut off the "phillips" part. 3 minutes with the belt sander (yeah, you machinists are cringing) and I was in business, flat tip with a steep enough angled cone to keep the shaft area of the pusher safely behind the skirt in the die.
Measured those best I could with a caliper and head size was about 0.210. Tested a couple in the .20 sizer, and after a few adjustments could get them to a pretty consistent head size of 0.2 and skirt of 0.206. My comparison .20 factory were coming out of a tin of JSB 15.89s. The factory .20s were measuring 0.2 on the head, and .209-.210 on the skirt. So, the die has a bit steep taper than the factory .20s, at least from that one tin.
I'm able to push them through both steps of the sizing with just the screwdriver and hand pressure, no rubber mallet necessary.
Chambered one and it went in like butter, just as smooth as a factory .20.
The results...
(was pushing them a bit too hard into the stop and giving them a small flat, almost a meplat, was able to mostly do away with that on the second batch).
.
Also tried some of the 21 grain H&Ns...but no accuracy test with these
Texted some airgun buddies in my excitement and then couldn't get some targets out fast enough. Threw a target down at my guess of 50, 75 and 90 yards. (I got kinda close).
Test bed was the .20 Taipan Veteran (gun details here: https://www.airgunnation.com/topic/veteran-short-20/?referrer=1)
Started with hammer tension at the same place that produces 910fps with the 15.89gr JSBs for about 29fpe. Best guess is that they were throwing the sized down 18.1s between 830 and 860).
First 5 shots @ 46 yards
First 5 shots @ 71 yards (with 1mil elevation added to the turret)
And then about 15 @ 92 yards (top three up in the orange were the last three, FAR below reg pressure so fps was up so they hit higher).
I felt like they were maybe "chambering" a bit too easy and was curious if a slightly bigger head would improve accuracy. So, quick adjustment of the .20 stop and I could get them to a head size of 0.201-0.203 with a skirt of about 0.209-211. Still chamber very easily, with just a touch of resistance, about like chambering an OEM JSB pellet.
Also decided to up the power and bit and get out the chrono. Went one half revolution "in" on the hammer tension to get to here (5 shot average at the muzzle).
So about 31-32fpe.
At that point figured I might as well try to capture a BC too....
This is a 5 shot average @ 45 yards.
Might vary with the calculator used, but I'm getting a BC of 0.042 with the one that I utilized. That's better than I've ever captured from the 18.1s as .22s (BC of 0.035).
So, accuracy with the slightly larger head and increase in power.....
5 @ 46 (the new holes, compare to previous 46 yard target)
5@71 yards (new holes again)
and about 25 shots @ 92 yards (entirely new paper here)
The upper right hole was my guess at turret elevation, took it down some after that first high shot. From there I didn't do any adjustments for wind or anything else, just held on the middle of the orange. The holes off to the right are where the wind was pushing them as it was a bit gusty. But the bulk of them in that main cluster are a pretty good representation of what it can do.
All shots taken from horribly uncomfortable prone position (breaks my neck every time). I could shrink them with less caffeine and more sleep in my system, and from a bench, and holding off for wind.
Overall better results than I was afraid of. I think the factory .20 (15.89 Heavies) are slightly more accurate and gave a little better measured BC, but there's potential here that I'll investigate further in the future. I'd like to accuracy test some of those 21 grain .22 H&Ns and maybe even some of the 19.6grain cast pellets from the .22 NOE pellet mold I bought a few years.
So, it can be done, with perhaps not stellar/excellent accuracy, but at least decent accuracy.
Pretty happy with the TR Robb sizers. Only using calipers to measure but results seem to be pretty repeatable and it's a pretty quick process, even with the two stage size reduction. They can't increase the size of course, but I'm curious to see if the .22 sizer could be used somehow to homogenize some of my lower quality batches of .22 Monster RDs that seem to be so exceptional at long range, but have a flyer or two every so often.
I've so far had a lot of fun with this and just wanted to share.
s mike, can of 
)