When breaking down a “new” BCG the cam pin does not clear the carrier key. It is one that was advertised as a RRA Enhanced BCG, but is probably 2 years old and unused.
Upon inspection and comparison to a BCG that comes apart no problem, I can’t visually see any difference between the two. Is the cam pin or the carrier key the most likely hang up? The carrier key lines up perfectly with the gas tube and appears to be staked well. I can see that it is chrome lined as well.
Are you rotating the cam pin 90 degrees? I’ve seen Model1sales carriers that won’t disassemble.
Yeah, it just BARELY does not clear. which makes me think it’s barely out of spec and maybe assembled with a mallet.
Bottom of the bolt cam pin through hole may have been improperly pressure staked.
Bottom of the through hole is pressure staked to keep folks from assembling the bolt into the carrier backwards and too much material was probably displaced into the bottom of the hole.
Try assembling the bolt and carrier using another bolt and see if the cam pin will set down correctly with a different bolt in place.
If so you can clean up the through hole on the bolt with a round ceramic stone if it isn’t chrome plated.
Worse case you will have to have the bolt through hole taper reamed to clearance enough material to allow the cam pin to fully seat.
If the bolt is a cheapo and doesn’t have the pressure staking or it is very lightly staked, make sure you aren’t assembling the bolt backwards into the carrier.
Extractor side of the bolt goes to the ejection port side of the carrier assembly.HTH
I had the same problem with an RRA BCG a couple of years ago. If you search the archives on TOS, you may be able to find it.
I used to have to pry the cam pin with a screwdriver, process that took about five to ten minutes. And when re-assembling, I would have to use a mallet. No performance issue, but taking it appart was annoying. I contacted EagleFirearms and they send me a new RRA BCG, no questions asked. The new one did not have that problem, but had two burrs in the rear that chewed the crap out of the buffer.
After these two incidents and more extractor problems, I decided to go with BCM.
Thank you, I got mine from Eagle Firearms too.
Just file the carrier key a bit where it needs it. This is maybe not common but not unheard of.
I was going to say that, but I figured people would just call me a hack so I kept quiet. 
Thanks for speaking up.
Naw, we already knew you had a Ph.D from Hack-Fu Gunwerks! I only have a Masters from there! 
BAH!
How many other gunsmiths do you know that dress their permanent attach welds with a surface grinder?
Thanks for the feedback.
Randy, you callin’ me a hack?
That’s quite a setup for dressing those welds-- obviously you’re a perfectionist!
I dress my permanent welds. If I can, I put them up into the attachment so that I can just drill a hole through the side, install it, and plug weld from the barrel up flush and grind , file, and sand smooth.
Guilty as charged.
Anybody try another bolt yet?
Dang man… I usually just file them down, or if the weld is significant enough I turn it, then I blast the whole FH and re park. You my friend are the very definition of perfectionist.
I used to rough grind and then finish by turning on the lathe.
With the differences in hardness, you get that irregular finish while turning.
Doing it on the surface grinder leaves me a perfect finish regardless of the hardness differences through the heat affected zone.
Then I can nicely touchup blue the area I grind.
I do get complaints about this once-in-a-while.
The complaint is that people can’t find the weld and want to make sure that I actually DID weld it. :eek:
I just tell them to look at the inside of the blank firing adapter grooves and they will see the heat effected zone.