Rate of twist, bullet weight, and a confused look on my face....
I've been shooting mostly 55 grain FMJ ammo in my AR's because they shoot it well, and I have me a fair bunch. On occasion, I've shoot the 62 grain green tip in them, with mediocre accuracy. Certainly noticeably larger groups than the 55 grain bullets.
But the thought keeps ringing in my brain: My AR's have 1 in 7 twist rates. They are SUPPOSED to shoot heavier bullets better...... %$#@ it. Before I begin ordering heavy bullets by the bin full, I thought I would just give something a shot. I bought a single lone box of Hornady 75 Grain Super Match ammo. This stuff costs like gold, and by accounts is one of the best AR match loads on the market. Want to see what happened?
This rifle has a Spikes heavy barrel upper with a mid-length gas system, a 1/7 twist, and a 3x fixed Nikon optic on it. I shot it from the bench, on a decent rest but still hand held. My heart beat was weaving the cross hair a good inch across the bull as I did my breath, breath, squeeze. The groups were fired three rounds at a time, with cooling time in between. The target on the left, 55 grain PMC Bronze bulk ammo (The one flier was called). The target on the right, the 75 grain Hornady $uper Match. I shall note.... if I had shot the 62 grain M855, the group would have fallen between these two in size. I'm open to suggestions here.