I just put together an 11.5 pistol and took it to the range today. It’s not my first build but it is my first pistol
Ballistic advantage carbine gas 11.5 barrel with fsp
BCM BCG
H2 buffer
PSA LPK (I know)
SBA3 and normal carbine receiver extension
I was getting consistent failures to eject that were causing double feeds and even a bolt over base when I used Federal M193 no matter the mag (Pmag M2/M3 and Okay USGI)
Russian steel case worked better but still multiple malfunctions of the same type per magazine.
I performed a lockback check and it locked back every time. One interesting thing I noticed was that when I fired the gun without a magazine inserted, the brass fell out of the magazine well. I only did that one time though.
The gun was lubed but not dripping
Brass ejected at 3:30-4:00 with steel and 1:00 with M193
My guess is that it needs a heavier buffer and possibly an extra power spring too. I emailed Ballistic Advantage and they told me to start with a carbine buffer and figure it out from there but that seems like a waste of time.
Gas block is pinned from the factory and looks straight to me. I was able to zero the gun so I doubt it’s out of alignment. There doesn’t appear to be any gas leaking at the gas block either
Buffer spring is standard carbine spring that came with the LPK but I also used a BCM spring but it didn’t help. I tried an H1 buffer too but that did nothing to help.
The gun locked back every time and feels more overgassed to me than a midlength so I don’t think it’s a problem of not getting enough gas
Extractor spring is a five coil with the black insert but no o-ring and it’s from BCM (it’s got a brand new BCM BCG) I was under the impression that BCM’s were on par with the Colt ones.
What makes the Colt or Springco ones different or better?
Start with the Bolt.
Add the O-ring
Colt or Sprinco extractor spring is a good idea for any of your BCGs
Use a different bolt
PSA action springs are not a good choice
I don’t think its the buffer. If you’re tossing Wolf ammo at 4:00 and true 5.56 ammo at 1:00, this means the 5.56 ammo is hitting the brass deflector on your upper and the Wolf ammo is too weak to make it to the brass deflector.
I’ll replace the extractor spring and add the oring and see how it runs tomorrow. I’ll use the spring from my BCM lower too since the PSA is crappy and might be causing this. If that doesn’t work I’ll swap out the current BCG for the other BCM one I’ve got.
Hopefully that’ll fix my issues and I’ll be able to enjoy my new pistol!
I realize the BCG is new, but how long ago did you buy it? IIRC, about 6 months to a year ago there were reports of BCM running into a bad batch of extractor springs.
I honestly don’t know. Colt designed the M4 extractor spring to solve the extraction issues that cropped up when the military started using the M4 extensively in full auto. In my own personal experience, I’ve seen quite a few extractor springs from other sources fail, usually between 500 and 1000 rounds. Since I replaced all the extractor springs in my ARs with Colt springs, a lot of problems went away.
I’ve never used the Sprinco spring, but I.G. has. He’s seen many times more ARs than I have and knows what works and what doesn’t. He says the Sprinco springs work.
If you use a Colt or Sprinco spring, do not use an O-ring. It will make the extractor too stiff. If your (5.56) extractor needs an O-ring, it needs to be replaced and upgraded. (308 extractors can be another story.)
I had a similar experience last year with a 10.5" BA (Modern series) and new PSA nickel boron bcg. New pistol with H buffer. First round goes, extracts, 2nd round jams. Went through that 4-5 times. Same deal with carbine and H2 buffer. Ammo was PMC X-TAC 5.56. Normally an excellent range-round for me.
I had my 8.5" pistol with me. I swapped its basic PSA bcg and the 10.5" did fine no matter which buffer. The shiny PSA bcg did fine in the 8.5". Perhaps the extractor was picky, gas differences, etc; who knows. I have since tried another bcg (PSA) in the 10.5" and it has functioned fine.
I changed the extractor spring for another BCM one that I had laying around and at first it worked great with the same mags and ammo as yesterday. After a little while the same FTEs started happening so I switched out the BCG for my other BCM one and the gun ran perfectly. I was skeptical of it running so well so I put the original BCG back in and had FTEs every single time.
It’s definitely got something to do with the BCG. Should I just send it back to BCM and be done with it?
I also tried magtech 62 grain 5.56 and had better reliabilty but still had a ton of malfunctions
And I should add that the BCG was fully lubed this time with CLP instead of the light coat of lube it had on there yesterday.
Yes - I have had two BCM BCG with the same issues. one older from 2013 that they replaced and one newer I have not had the time to do anything with yet.