Seekins SP223 Upper and JP LMOS BCG

[Goes-Bang]

I know when I was researching AR10 stuff, I read that the headspace on a JP BCG wouldn't line up with the Seekins SP10 upper.

Anyone know if that is also true for the SP223 uppers, or are those more standardized? Can I use the JP LMOS BCG in a Seekins SP223 upper with a seekins barrel?

Thanks!

 

[TonyTheTiger]

In any given match weekend I might see 10 Seekins uppers with JP hardware in them. Its good to go in small frame, can't speak to large frame.

 

[shax2lex]

I would say ask Seekins Precision about their bolt and BCG compared to the JP bolt and BCG. There’s no standard so kinda tough to say.

 

[TonyTheTiger]

There’s no standard so kinda tough to say.

For small frame?

 

[Bigjake83]

As far as the small frame compatibility you're good to go, and in regards to your above statement, are you referring to using a complete JP BCG in a seekins upper with the seekins barrel?? Then no....

But you can definitely use a barrel that is headspace for a JP BCG in a seekins large frame Upper/Builders kit.

It sounds to me like you're trying to slap JP components into an already assembled seekins complete upper? If that's all you're after just keep the seekins headspace Bolt and buy a JP carrier.

 

[shax2lex]

Well I messed that up. Sorry I was talking about there is no real standard for AR-10s.

 

[shax2lex]

I’m definitely interested in this thread though. I have a Seekins 3G2 complete rifle and I’d like to change out the bolt,
BCG, and buffer/spring to JP stuff. I’d hate to have to get a new barrel.