I recently completed my first upper build from scratch and I am having problems with light primer strikes. I"ve put 30 to 40 rounds through it and have had 5 or 6 light primer strikes. When I try the rounds again, they still barely have a dimple from the firing pin. PPU 120 grain hollow points are all that I have shot through it so far.

18" .264lbc type I Blackhole weaponary SS barrel
JP 6.5 grendel bolt & firing pin
PSA bolt carrier
syrac ordanance adjustable gas block
Aero upper with m4 cuts

prvi partisan 120 hollow points

I am at work and can't post pictures right now, but I can later.
I am thinking that the bolt is locking up enough to allow the firing pin to travel, but not enough to allow a full strike?
Is there a difference in the JP 6.5 bolt and the BHW 264lbc chamber that makes them incompatable?
Any Ideas?

Thanks for any input.

I don't have the knowledge to help you, but I love the 6.5 and that is something I hope to do someday so I hope you get this issue worked out.  Good luck.

Try a stiffer hammer spring about $10.00. Or a longer firing pin about $20.00 should fix your issue. Or try both
I have the same barrel as yours I love it.

I'm not seeing a trigger assembly in your list. Was it a drop-in, or a Lower Parts Kit that you installed yourself?  Did you maybe install the springs incorrectly?





Did you buy a matching bolt/barrel?  It's very rare to have a headspace issue with AR-15 barrels, but it can happen.  And too much headspace can cause light primer strikes.

 

 sirronn:  You may be right, the bolt has perhaps not fully mated with the barrel extension.  I suggest you apply some light oil to both parts and then manually work the carrier assy back and forth in the receiver a couple hundred times.  Then thoroughly clean, including the chamber, reapply lube and try at the range again.  I also suggest you try some US made ammo, in case the Prvi ammo is to blame. The trigger could be the problem, but that's unlikely since it would be readily apparent when the lower is separated from the upper.  - CW

http://palmettostatearmory.com/index.php/ammunition/rifle-ammunition/6-8-spc.html

The lower uses a standard PSA lower parts kit and I swap uppers often and haven't had a single issue with this lower, or any of the other lowers I have build myself. I do have another lower I could put the Grendel upper on and see if that changes any thing. The barrel and bolt were purchased seperately, and it very well might be a head spacing issue. I'll try different ammo and look into an enhanced firing pin. Thanks for the suggestions.

Is your BHW barrel chamber cut for a BHW Type 1 or Type 2 chamber/bolt...This maybe your Issue...also, try using different ammo
to see if you have the same Issue (possible hard mil primers)...then check your trigger group/springs...and lastly check your firing
pin for a defect/chip/non spec length...use plenty of lube.

Good luck.

https://www.youtube.com/watch?v=DZncepUMgBg

Thanks for the video. It was the bolt. I bought a 762x39 bolt and that fixed everything. I thought I had read everything about Grendels before I built this one, but I guess I missed the part about different bolts for different barrel manufacturers.

Glad it worked out for you...I suspected it was a bolt Issue, in this case the bolt type (type 1 or type 2 as BHW refers to it).

Also, while the differences are small, a .264 LBC chamber is NOT a true 6.5 Grendel chamber and this may use different
bolt face depths...than can cause possibly dangerous head-space Issues and such if you wind-up with the wrong bolt...

The best way to help avoid this problem is to buy the barrel/upper with a pre-fitted  bolt that has been head-spaced to the barrel.