Originally Posted By slipjett:
Originally Posted By Keigan:
DPMS did not return the part that I asked and paid them to replace. The rifle now shoots straight. It was raining this weekend, so no pictures, maybe next weekend.
That is correct..... I sent the rifle in for two warranty concerns, trigger and accuracy. They adjusted the trigger no problem, but we agreed to disagree regarding the accuracy of the rifle. Fine.... The barrel works fine, holds sub-moa at 100 yards without trying - my concern regarding the accuracy was that the barrel seems to not be aligned with the upper receiver.
a) the air gap between the gas block and the free float hand rail was not the same on left side and right side, right side was significantly less then left side - one could conclude that:
a.1) if we assume that the barrel was aligned to the upper receiver, then there must be some manufacturing tollerence concern with the free float hand guard that is producing the differences in gap between the gas block and the inside of the free float hand rail
a.2) if we assume that the barrel was not aligned to the upper receiver, and that there were no issues with the manufacturing tolerences of the free float hand rail - then we could conclude that the air gap differences between the gas block and the inside of the free float hand rail are caused by the barrel not being in alignment with the upper receiver
Precision rifle test:
If a scope is zeroed on rifle A, mounted to PIC Rail on upper receiver - you should be able to move the scope and mount to Rifle B and things should be "close" for the zero. that is assuming that Rifle A has the barrel in aligment to the upper receiver, and Rifle B has the barrel in alignment to the upper receiver.
I have access to two DPMS SASS in .308 - Rifle A and Rifle B
Leupold Mark 4 zeroed on Rifle A at 100 yards, then moved to Rifle B - same day, same ammo, same conditions.... Rifle B POI is 11 inches to the RIGHT based upon the scope move. Inspection of Rifle B showed a significant bias of the air gap on the gas block to the inside of the free float hand rail - indicating that the barrel was pointing more RIGHT than centered. BTW, yes I have anti-cant devices on both rifles and the bubble was zero at time of testing.
Rifle B was sent in for the warranty work, DPMS Techs confirmed that the rifle holds sub-moa accuracy at 100 yards - but we agree to disagree regarding the importance of barrel alignment to the upper receiver. Fine, replace the upper receiver, cost me about $200 for new upper receiver and labor.
They did not return my original upper receiver, I did not care to chase it down with them. I suspect that detail measurements on the upper receiver would tell the truth. The rifle now shoots sub-moa so I am happy, the scope move between Rifle A and Rifle B required only two clicks to adjust POI to POA.