.22 lr in Mini 14

[Spike]

...same bullet diameter...

...223 barrel has a MUCH faster twist rate.... which can cause accuracy issues.

I see. Almost twice as fast. I can imagine.
-S

 

[Snake45]

Standard .22LR twist is 1:16. I'm shooting an M261 conversion in an old 1:12 barrel. I had one lot of ammo that would print 1/2" groups at 25 yards (which is almost as good as my "real .22s," which average 3/8" or better), but more normal performance is just inside an inch. My regular use for this rifle is offhand practice on 1/6 scale silhouettes at 50 feet; these are about 3" wide so "possibles" are achievable.

I have one 1:9 AR upper and I tried the Aguila 60 grainers in that (Aguila recommends a 1:9 twist for this ammo). Every single 5-shot group was a 4+1 with four shots in a nice 1/2" and the fifth 1/4" to 1/2" out every time. Disappointing for what that ammo costs. I only bought and shot the one box.

There's a difference in bore diameter between .22LRs and .22 centerfires, too. I think it's .223 vs .224, with the rimfire being the smaller. I miked all the ammo I tested in the 1:12 barrel and the fattest were Federal Champions, averaging about .225. They should have been the most accurate but were in fact the least accurate ammo I tested. Go figger. :?