I also have another test set for the 308, since it turns out that threading the muzzle and putting the brake on it changed the harmonics enough that it no longer likes the load I had developed for it, with or without the suppressor.

I know it’s not a crown issue, because a totally different load still groups beautifully, maybe even better than before. But I can’t find those bullets anymore (150gr Remington accu-tip), so I don’t want to shoot them all up.