[yarddog]

At one time I had four AR-15 H-bars. Each came from Colt with a Ciener .22LR conversion kit. Since the H-bars had a 1 in 7 twist which is much faster than regular .22 rimfire barrels, I was surprised just how well they shot.

I suspect that spinning the bullet too fast is less harmful than too slow.

[KoRn]

"I suspect that spinning the bullet too fast is less harmful than too slow."

I believe there could be a lot of variables at play, preventing a blanket conclusion. Twist, combined with barrel length, bullet weight.... ect....ect. In other words, the tighter twist may NOT be ideal in every circumstance. You might have found one where it was.

[kitchen]

Did you ever try the Aguila 60 grain subsonics? I've seen recommendations of a minimum 1 in 9" twist. On the other hand, there's a lot of lead exposed to gum things up.

I've been scouting around for an older .22 bolt with plans to reline the barrel specifically for this round.

[Myrddin]

Most .22LR are 40 gr bullets. They are stable at 1:14. Heavier (longer) bullets need a faster spin. A 55 gr works better at 1:9. The 69 gr and 72 gr need the 1:7 rate for stability. A faster spin doesn't hurt except when you have a thinly gilded (plated) bullet. I've seen them spun too fast and literally disintegrate in flight. The powder charge behind the .22LR rimfire can't drive it hard enough to do that.