I am now the happy owner a hardly used Colt Blue Label preban.  My question is concerning how tight the mag well is.  The 20 rnd mag it came with fits good and drops free but my two (2) Okay 30 rounders fit pretty tight and don't drop free and my six (6) Thermolds are the same way.  I've adjusted the mag catch out as far as it will go and they're still tight.  They are not tight at first only towards the end after the mag catch.  What could be causing this?  Too much finish in the well.  Out of spec mag well?  Has anyone else experienced this?  What can I do about it?

btt

Well, I suppose you could first get one of your AR's that work o.k. with the mags you have.  Then measure the top and bottom of the mag will opening to see if is the same, or if it tighter, or tapers too much.  Next, (or maybe first), mesure the mags that work and then measure the ones that don't and see if they spec the same.  It's either one or t' other.

Your mags are the ones out of spec. 20 rounders hardly puff or expand.. 30 rndrs do expand and sometimes its good to squish them with your hand kinda pinch them.....back in to shape....I have negver had a thermold drop free. ever...were talking colt bush asa and dpms rifles that why I dont buy them.