Mixed Receivers

[TheChewycookie]

What has been y'alls experience mixing receivers? I'm looking for results mixing something like a QC10 lower and Foxtrot Mike upper as an example. I've read and understood that it's better to stick with one brand because of tolerance stack between companies, I'm just curious to read what you have done before I jump in.

 

If you swapped around uppers did you also have to mod/swap the ejector?

Have you tried other blowback systems in-combo with your regular lower, like CMMG's radial-delayed blowback?

No need to include buffer/spring combos, triggers, comps, etc. I somewhat have a build idea in mind.

[dfwmiket]

Running Spike's Tactical lowers and have used 3 different uppers w/ no issues. Have used a Taccom setup and also used 16" barrel/comp setups.  

 

-Mike

[EarlKeese]

FM9 lower/Taccom upper without any issues. 

[stick]

Almost all of my 4 PCC"S now have mixed uppers and lowers.  It's a modular platform.  You can swap them or interchange them without issue most of the time.  The only issue I have is with one upper fitting really tight into the lower.  You need to tap out the pins with a punch.

[TheChewycookie]

Guess that answers the question. Thanks!

[Texaspaul]

I have a split, two that match QC-10 & FTM-9 both side chargers the other three have a mix match all work.

[RickT]

I run CMMG uppers with AR lowers using Mean Arms Pmags.  Not sure the CMMG bolt is compatible with a blowback lower's ejector since CMMG uses an AR style ejector.

[Chillywig]

For the most part ARs are legos for adults. Mix match build have fun

[Eric802]

27 minutes ago, RickT said:

I run CMMG uppers with AR lowers using Mean Arms Pmags.  Not sure the CMMG bolt is compatible with a blowback lower's ejector since CMMG uses an AR style ejector.

And I think those are probably the CMMG-specific Mean Arms inserts, right? The regular ones have the ejector built into the mag, and I recall an issue using those with the CMMG bolts; people had to trim the ejector tab off the mag insert.  

 

The ejector set up is probably the only are where you're really going to run into compatibility issues.