I would go for the accumark and see how it does first. I've had quite a few and never one over moa. I rebarreled my 257 with a lilja and it will shoot .25-.5 moa now. but until it opened up always shot .5 before. I wouldn't try anything closer than 200yds too for an accurate representation of...
What kind of brass are you running through it? Have you tried a factory load? It sounds like it is short stroking and once oiled a lot it gets far enough to get the empties out and snag a new one. If it is relatively hard to pull back it is a 308 spring. Not much else available out there for...
The druthers from shooting factory ammo, but when it shoots like this and way better with good hand loads it will stick with the bolt guns no problem.
Noreen Bad News 338 Lapua semiauto 1014yds