Re: .223 subsonic
I have not tried any bullets heavier than 60 grain yet in my subsonic experiments. I did shoot some 55 grain soft nose yesterday though. Shot out of a 16" bbl 1/9 twist AR carbine. Bullets very stable at 50 yds, but at 100 yd target, you could tell from the holes they were beginning to wobble a bit. Out of 10 rds, 3 hit nose up, 4 nose down, 2 nose right and 1 nose left. They weren't keyholing yet, but on the verge. This was 55gr soft nose flat base, 4.4 gr Trailboss, CCI #41 mil primers, mixed brass. They are plenty stable leaving the barrel, but the farther they fly the less stable they become.
I also shot some 55gr FMJBTs with the same results and same load.
I even tried seating the FMJBTs backwards. (Don't try this at home...) They were stable leaving the barrel, but at 50 yards were beginning to keyhole, and at 100 yds 90% keyholed the target. A few of them went supersonic and the supersonic bullets all were stable--even at 100 yds. Again, these bullets were loaded BACKWARDS and crimped into the cannelure. The flat base bullets would not feed in my AR loaded backward, but the boattails did fine.
I will add here that the backward FMJBTs appeared very stable at 100 yds when I loaded them with a normal full powder charge. They had the same point of impact and only slightly larger group as the same loads with the bullets loaded in conventional manner. The backwards bullets cut a very nice wadcutter-type hole in the targets and would surely apply more shock to a varmint than a conventional FMJ load.
I am not in any way suggesting you load a bunch of bullets backwards---I just did this for shits and grins.
ALWAYS do thorough testing of subsonic loads WITHOUT the suppressor until you are sure the bullets are stable leaving the barrel.
