Oh wise and gentle 2A comrades, I present to you an annoying difficulty.
The rifle:
DPMS LR-308 lower (originally a factory rifle, but the upper was the high top pattern). Swapped to DPMS-compatible barreled upper in 6.5CM (24") that is properly headspaced. Using original 308 bolt, significant pressure signs (case swipe, blown primers, etc.), double feeds, FT Eject.
Added an adjustable gas block, switched to a high pressure bolt (and upgraded the trigger, but I don't see a relation there). I also polished the chamber. Pressure signs are gone, and the feeding/ejection problems are less frequent (but not that much). Every third or fourth round the carrier appears to be extracting the spent casing, strips a fresh round which ends up full seated in the chamber, but then stovepipes the spent casing between the bolt and the forward edge of the ejection port (literally half in/half out).
The pre-Creedmoor transplant parts left on the rifle are: lower, carrier & carrier key, carbine buffer tube, buffer and spring. Also, still using the [not quite] 20 round DPMS steel box mags.
My suspicions for the source of the problems are:
a) extractor is failing to release (I polished it, but I haven't taken a file to the horns);
b) buffer/spring is too weak;
c) magazines;
d) something I am missing.
Those options are about in the order of cost/expense/headache to deal with, but I figured I would seek input before heading over to Midway (or Chantilly for option c)... I really want to get this resolved because the accuracy is phenomenal, but that is useless if it isn't reliable...
The rifle:
DPMS LR-308 lower (originally a factory rifle, but the upper was the high top pattern). Swapped to DPMS-compatible barreled upper in 6.5CM (24") that is properly headspaced. Using original 308 bolt, significant pressure signs (case swipe, blown primers, etc.), double feeds, FT Eject.
Added an adjustable gas block, switched to a high pressure bolt (and upgraded the trigger, but I don't see a relation there). I also polished the chamber. Pressure signs are gone, and the feeding/ejection problems are less frequent (but not that much). Every third or fourth round the carrier appears to be extracting the spent casing, strips a fresh round which ends up full seated in the chamber, but then stovepipes the spent casing between the bolt and the forward edge of the ejection port (literally half in/half out).
The pre-Creedmoor transplant parts left on the rifle are: lower, carrier & carrier key, carbine buffer tube, buffer and spring. Also, still using the [not quite] 20 round DPMS steel box mags.
My suspicions for the source of the problems are:
a) extractor is failing to release (I polished it, but I haven't taken a file to the horns);
b) buffer/spring is too weak;
c) magazines;
d) something I am missing.
Those options are about in the order of cost/expense/headache to deal with, but I figured I would seek input before heading over to Midway (or Chantilly for option c)... I really want to get this resolved because the accuracy is phenomenal, but that is useless if it isn't reliable...