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1 BCG - 2 Barrels


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I know this has been asked before, but I'm wondering about additional issues:


If I've got two uppers

1. 20" Heavy barrel

2. 16" regular contour

-Both are Rifle length gas systems.


BCG is properly head-spaced to work with either barreled upper.

One lower: with PRS stock and standard DPMS length buffer tube with Slash's Heavy Buffer.


Will there be any expected cycling problems putting either upper on the same lower?  

Will pressures really change that much?  

Will I need an adjustable gas block on the 16"?


(This is all running unsupressed, btw)





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If you absolutely need to use the same bolt carrier, that's one thing. 


Buy a bolt for the other barrel.  Keep the bolt and barrel matched, and don't swap $hit around.  Keep their wear, together, the same on both different uppers.

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Nope.  As long as it functions.


Example:  Complete DPMS rifle, obviously the upper and lower should have matched machining (coming from the same factory) that permit them to operate together.


Now, same DPMS lower, and say you buy yourself some billet upper that's supposed to be DPMS format - if that thing doesn't run, you'd need to look at the machining on that upper, very first, make sure it's right - then move to gas system issues.


We've seen it happen, right here.  Guns that don't run right, and upper and lower are made by the same company...  One company comes to mind on that.  We've seen a BUNCH of mix-n-match stuff that won't run, either.  Different people machining, based on what they think the pattern is...  It ends up not really an "Apples and Oranges" thing.  More of an "Apples and Hammers" thing...  <lmao>

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