Also I have noticed that in the break in period some real good lube works great too. I use it liberally on the bolt and the guide rod and the guide block. I have not had issues at all using 1200 fps ammo, however I do have a xn model.
This is the lube I use ( archoil AR 4200) and found it to be the best after trying about 12 different ones that all claimed to be the best. I have no affiliation with the company and have to buy the stuff just like everyone else. A little goes a long way.....
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