BCG not going into receiver

[Gunny Jake]

It's difficult to put into words.

 

[Gunny Jake]

Both uppers are gas type right? Neither is piston?

 

[331coupe]

Both uppers are gas type right? Neither is piston?

Correct both DI uppers and all DI bcg's

 

[Gunny Jake]

Try putting it in without the firing pin retaining pin installed, just to see if it will slide in. If it does then one UR has a tighter tolerance and you'll have to file the retaining pin.

 

[331coupe]

Try putting it in without the firing pin retaining pin installed, just to see if it will slide in. If it does then one UR has a tighter tolerance and you'll have to file the retaining pin.

It doesn't make it in far enough for the retaining pin to even be the hold up if that makes any sense.

 

[Gunny Jake]

Let me see if I'm picturing this correctly. You have an upper receiver that will not accept any bolt carrier group?
If this is correct then flip the UR upside down and smack it. Then attempt to install the BCG while the UR is upside-down. I'm not being a smart-ass. There are fasteners and receptacles on top of the inside of the UR. If something is loose and hanging then it can block the path. I'm gettin off my ass now and fixin to take a pic of what I'm attempting to explain.

 

[331coupe]

Let me see if I'm picturing this correctly. You have an upper receiver that will not accept any bolt carrier group?
If this is correct then flip the UR upside down and smack it. Then attempt to install the BCG while the UR is upside-down. I'm not being a smart-ass. There are fasteners and receptacles on top of the inside of the UR. If something is loose and hanging then it can block the path. I'm gettin off my ass now and fixin to take a pic of what I'm attempting to explain.

No it will take multiple other bcg's that I have but not the particular one that I'm talking about. But this bcg that I'm talking about will go into another receiver.

 

[Gunny Jake]

What would cause BCG A. to fit into one receiver but not another one, but BCG B. and C. will fit into the receiver BCG A. wouldn't. Hope that makes sense lol. and I mean like won't even go an inch into the receiver.

I keep reading this and getting dizzy, lol. This is the excuse i needed to make another drink.

 

[331coupe]

I keep reading this and getting dizzy, lol. This is the excuse i needed to make another drink.

I'm saying I have 3 bcg...call them A, B, and C. Two of the bcgs (B, and C) fit in this upper reciever while one (A) doesnt. The one that doesn't (A) fits into another upper receiver just fine.

 

[Gunny Jake]

No it will take multiple other bcg's that I have but not the particular one that I'm talking about. But this bcg that I'm talking about will go into another receiver.

Can you take a pic of the two BCGs side by side? I'm gambling that the gas port that will go in has more of a ramped leading edge or the protrusion on the left side is too wide for the groove inside the UR. It sounds like some minor filing is required, we just don't know where yet.