Post by mefunkymxw on Sept 16, 2013 6:37:42 GMT -8
Prior .223 BHW AR owner, and just completed a 6.8 build with a BHW specII chamber. This is my first post on this forum. I am a prior 6.8 shooter on a Rob Arms XCR platform (more then likely a spec I chamber since i bought it over 3 years ago) and do handload (primarily 115 grain nosler HPBTs over 27.0 grain H322).
I just got my new barrel from blackhole and it is 18" with rifle length gas tube, and yesterday, after assembly I had difficulty extracting on every single one of the 40 rounds I put down range. normally on an AR I would attribute this to a canted gas block, but I validated the alignment twice. After assembly I did check the headspace with my go and no-go gauges.... the bolt went into battery with the go gauge and would not go into battery with the no-go gauge. I was using S&B 110 grain partitions (SRP brass) at the range. I did notice that bolt would come out of battery, but did not have enough energy to extract the round (the extractor stayed in place on the rim). When using the charging handle I did have to use some energy to extract the cases (more then I would have thought).
I did measure the shot cases which came in at 1.693" or so, which is above the max allowable of 1.686", so that could attribute to the FTEs but I am not sure. I wanted to get some of your all's input as to what it might be. my build is as follows:
18" BHW 6.8 SPEC II with .75" profile past gas shoulder
midwest industries billet upper (non-mil spec)
BCM micro gas block (.75")
BCM rifle length gas tube
midwest industries rifle length FF handguard
LWRC NiB 6.8 bolt face
SMI NiB bolt carrier
barret 6.8 muzzle brake
Noveske chainsaw lower
spikes tactical enhanced trigger group (NiB coated hammer, trigger and disconnector)
magpul UBR stock (carbine length)
spikes S2-T2 heavy buffer
bravo company carbine buffer spring
magpul MIAD grip
the major things i want to troubleshoot are:
1. the buffer, i might switch it out for a standard weight buffer for testing
2. ammo, i have hornady, remington and handloads that i know probably have better QA then S&B
3. recheck the gas block alignment, i do have a compressor so i can test air flow in the barrel
4. unrelated, but i did notice that i was having some trouble feeding some HP nosler rounds and i think this was due to the mismatched feed ramp widths between the BHW barrel and the MI billet upper, the barrel has thinner feed ramps and as such some of he hp rounds were getting stuck on the ledge created by the wider upper feed ramps (can anyone recommend a good mil spec upper in case i want to replace my MI billet)....
any ideas would be appreciated.