I have no experience with the bonded 64 grain.
I've shot the 60 grain partition in a few guns. The 1-14" twist .22-250s and .220 Swifts gave me 3-4 inch groups with indications of keyholing. It has done better in a couple AR-15s with 1-8" twists .. maybe inch and a half best for 5 shots. While it is not great, depending on the distance, it may be good enough.
The best accuracy I've gotten from a hunting bullet in .22 was from the 55 grain TBBC in one of those 1-14" .22-250s .. just under MOA, and shot THROUGH stuff instead of merely shooting INTO stuff. Wasn't happy with the bloodshot but I sure can't complain about penetration.
If you can find them in time, the 70 grain Accubonds are shooting ok in those 1-8" twist ARs. I would definitely look to them as a candidate for a 1-8" twist .22-250.
Tom
