The mysteries of 22lr ballistics--what do you think?

[Picher]

My 10-22 shot this pretty nice bunch of groups: https://www.facebook.com/reel/917313929615894

[stagpanther]

Are you late with your rent and your landlord going to litigate? (no idea what that has to do with 22lr ammo LOL)

[stagpanther]

This thread got me interested in resurrecting this project and do a comprehensive comparison of the best subsonics I have to the best supersonics I have. While so far all my shooting has born out that subsonics are more accurate over-all; I never felt my Lilja build was really working optimally so decided to give it another try.



The barrel comes from Lilja with a set of shims and specific instructions on how to headspace it--which I followed to the letter. It worked, but it also frequently resulted in spent cases being left in the chamber. Bringing a ramrod out to the range to remove the case gets old really fast.

Comparing Lilja’s barrel to the stock CZ I noticed that the breach face of CZ’s has shallow notches to facilitate the extractors in grabbing the case rim, these notches are somewhat below the surface of the breach face—Lilja’s barrel instead has the bore wall go all the way up to the level of the breach face (I assume for better case support). In my opinion—that is the chief reason the CZ bolt sometimes has trouble extracting spent cases especially when using supersonic cartridges.



So I decided to file a couple of shallow notches where the extractors contact the barrel’s breach face to see if that gets rid of the extraction problem. It does. In the process I also was able to ditch the shimming headspacing headache. The tricky part is that the firing pin hits the case rim right at the same spot where an extractor groove is, so if there isn’t enough support there (which I found out by a test with the shims still on) higher-pressure loads will tend to bulge or blow out the case head in that area. Once I removed the shims the rifle cycled, fired and extracted with no problems—both low-pressure subsonics and high-pressure (1,400 fps or better) supersonics. Full disclosure—this was a rather rash “throw caution to the wind” experiment and I may have very well ruined the barrel in the process. I’ll see. I was getting what I would call “OK” results, at or slightly under MOA before I did the mod, but my CZ jaguar could easily best the best the Lilja could do. I also replaced the magazine well and magazine with CZ’s for 17 HMR/22WMR to accommodate the much longer cutting edge solid projectiles—works like a charm.

I’ve got a lot of time and money vested in the project—so I am very motivated to see the supersonic solids beat the subsonics—I just haven’t been able to do it so far. I've seen no evidence so far of gas escaping due to a bad seal.

[Rimfire5]

The data I have supports Stagpanther.

I can only report the experience that I and 3 other range buddies who shot a total of 18 different .22LR target grade rifles using 57 different ammos over about 5 years. I hope this long post provides data that most people don’t have the opportunity or the time to gather.

We shot 5 round groups at 50 and 100 yards and the total groups scored was well over 10,200 groups.
We recorded everything so the amount of data we gathered is daunting.
The shooting sessions were all from benches using scopes, so barrel length didn’t aid in sighting.
Shooting sessions extended over multiple years, outdoors, under temperature conditions from 45 to 90+ degrees, and with wind conditions that varied but rarely exceeded 10-15 mph.
While there were some variations in shooter ability, especially in ‘reading the wind’ shooting at 100 yards, the large samples tended to balance that out.
Barrel lengths ranged from 18 to 26 inches.
Bullet velocity ratings ranged from 1,050 fps to 1,085 fps for match & target ammos and from 1,200 to 1,255 for high velocity ammos.

Our results show that the accuracy was more dependent on the rifle and quality of the ammo rather than on barrel length.
Unfortunately, not all barrel bores are the same, regardless of length, and the higher quality barrels tended to produce better performance.
At 100 yards, the quality of the ammo was the biggest factor.

Results:
2 Cooper rifles (24-in), a Winchester 52C (26-in), and 7 Kidd semi-autos (20-in) had the best performance at 50 yards.
2 Cooper rifles (24-in), a Winchester 52C (26-in) and 3 of the Kidd semi-autos (20-in) had the best performance at 100 yards.

At 100 yards, the rifles shooting the best overall averages tended to shoot more of the highest quality ammos.
Laupa X-act, Midas Plus, or Center-X, and Eley Tenex or Match, and RWS R-50 or R-100 generally had the smallest group averages at both 50 and 100 yards in most rifles.
Those 7 ammos generally had the best results at 100 yards regardless of rifle, or barrel length.
(Eley Team and Edge, SK Rifle Match, Wolf Match Target averaged just over 1.0 in at 100 yards and were not used as much, once it was found that the higher quality ammos performed so much better.)

At 50 yards, the best shooting rifles, in order, were:
2 different Cooper 57M rifles with 24-in barrels
Winchester 52C with a 26-in barrel
7 different Kidd semi-autos with 20-inch barrels
Sako Quad with a 22 in barrel
Kimber SVT with a 18-in barrel
CZ 455 with a 22-in barrel
3 Ruger 10-22s (modified) with 20-inch barrels
Ruger American
Remington 541X
The best group averages were achieved with high quality, match ammos.

At 50 yards:
The top 9 rifles shot under 0.5-in averages with all of the ammos.
7 of those 9 averages were between 0.404 to 0.444.
The top 9 rifles averaged under 0.4 inches with high quality match ammos.
5 other rifles shot under 0.6-in averages for all of the ammos.
1 of the 5 averaged 0.500-in.
2 rifles shot just over 0.6-in averages for all of the ammos.
Averages were 0.609 and 0.610.
The last two rifles averaged under 0.8 inches for all of the ammos.

At 100 yards only the top 13 rifles were shot using the moderate to high grade match ammos.
(Even with the most accurate rifles, tests of high velocity ammos showed that they couldn’t break 1.2-in
averages at 100 yards. Several could not even break 1-In at 50 yards.)

At 100 yards, the top 6 rifles averaged under 0.9-in for all ammos shot:
Ammo quality and wind conditions tended to be a major factor in getting consistent results.
0.724 Kidd with 20 in barrel
0.808 Kidd with 20 in barrel
0.836 Cooper 57M with 24-in barrel
0.859 Winchester 52 C with 26-in barrel
0.865 Cooper 57M with 24-in barrel
0.891 Kidd with 20-in barrel

At 100 yards, the best ammos in the top 6 rifles averaged:
0.649 Kidd with 20-in barrel (Lapua Midas Plus)
0.658 Cooper 57M with 24-in barrel (Lapua X-Act
0.732 Cooper 57M with 24-in barrel (Eley TENEX)
0.747 Kidd with 20-in barrel (Lapua X-Act)
0.789 Kidd with 20-in barrel (Lapua Midas Plus)
0.823 Winchester 52C with 26-in barrel (Lapua Midas Plus)

[stagpanther]

I just got back from my first test which had some rather surprising results for me.

I started with Cutting edge's lowest charge for their 42 gr CURX bullet which is 2.1 grs. when using VV N350. Since the top charge is only a few tenths of a grain more and produced a velocity over 1400 fps for them--I just assumed the load would be supersonic. It isn't, even though the first shot sailed over two feet above where a Norma Tac 22 landed. I got an average vel right around 1150 fps--very similar to the better subsonics. Having said that, the SD and ED figures were horrendous.



Conditions were terribly, gusty crosswinds exceeding 20 mph, so I didn't see any point in going long and just wanted to record some labradar data--I set up at what turned out to be 52 yds. I wouldn't expect any kind of rimfire to group well in these kind of conditions.



I shot ten shots and was really surprised by the group (in previous outings I didn't get results like this even in calm conditions)--excluding the shot out to the right which I called as it broke because I pulled it--the remaining 9 shots grouped just a bit over MOA as far as I can tell. I didn't bother grouping any conventional lead ammo--I like to keep the two separate in bores. It will be interesting to see what happens when I push the same combo well past transonic/supersonic.

[stagpanther]

Interesting results rimfire 5--thanks for posting.