I've had the same issues when overspinning varmint bullets. They are even more explosive when spun that hard. I'd try moving to a tougher/heavier bullet or slowing back down to a 12-14 twist barrel. If i were shooting a 1:10 twist 250 I'd be looking hard at the 62 gr Vmatch. Or maybe a 1365 Sierra if the 62 didn't stabilize. If youre looking for blazing speed in a varmint bullet a faster twist isn't necessarily in your favor for coyotes.