.22 SSS (Sniper SubSonic) Rimfire

Another of my finds today at the range was this unusual (to me) .22 LR (?) round. The break of the bullet and brass in the picture is the length of the casing. Otherwise it is the length of a standard .22 Long Rifle round. Can anyone identify it for me? Thanks, Bruce.

Bruce, this is a subsonic .22 l.r. made by Aguila of Mexico.


Thanks, EOD. Looks like it holds a decent energy out to 100 yds. Cheers, Bruce.

Bruce: The problem with this loading is that in a typical .22 rimfire barrel the bullet is so understabilized it may well not go a hundred yards, at least not with any useful accuracy. Jack

Jack, why would it be understabilized?

When I first saw this interesting loading, I also wondered if it would have good stability.

I went to a website calculator for projectile stability that allows entry of bullet basics, velocity and atmospheric conditions to generate a number that is a factor of stability. The indication is that the factor should be between 1.3 and 2.0 for good results.

Using 60 gr./950 fps/.58" bullet length/ 70 deg.F/ 29.92inHg barometric pressure and…

a 1:16 Twist as was the last .22LR barrel I acquired.

The figure generated was 1.112 at the published muzzle velocity.
This drops to 1.072 @ 850 fps.

Are these recommended for a faster twist barrel?


Dave, this .22 SSS (Sniper SubSonic) cartridge was originally designed for a modified Ruger M77/22 rifle called “Poseidón” which had a 1:9 inch barrel twist.


Great info! Thank you very much.


Standard .22LR (subsonic) SK ‘Pistol Match’ (Lapua Schönebeck) is stable and very accurate out to 100 meters. I use it regularly at field shoots in my Pardini SP and have absolutely no problems hitting center of the target (1meter x ½meter) at 90-110 meters distance, if I do my part.