My .308 rifle is cycling flawlessly with 168 grain and above ...however I purchased plenty rounds at 150 ish during the lockdown that do not seem to like my homebuilt.
I purchased completed upper from reputable source. Also purchased larger / heavier buffer from Cliff @ heavy buffers and only concern is why not performing with lower grain ammo.
Mahalo for your feedback in advance,
Aloha,
Jeff