I've got a PWA and a Bushmaster. Some USGI magazines are a tight fit in the PWA and a lose one in the Bushmaster. Is there anyway to fix this or should I just use the tight mags in my Bushmaster?

Thanks!
mrf2

ADJUST THE MAGAZINE BUTTON A COUPLE OF TURNS OUT

30 rounders spread at the rear corners of the feed lips with use.  

you can guage your receivers with a brand new USGI mag to make sure you don't have a tight mag well.  A new usgi mag should drop free from your receiver.

An older mag that doesn't drop free may still be good and functional however.

The threads on the mag catch should be adjusted to be flush with the touch surface of the button.  In this position, it should easily clear the mag when pressed.

I have seen both new and well used mags that are too tight or too loose.

With too tight mags:  Separate the upper and lower.  Insert in the offending mag.  Use feeler gauges around the mag to see where it is rubbing against the lower receiver/magwell.  It has been my experience that 95% of the time, it is at the front and rear seam.

The overlap at the seem puckers out between the spot welds, and rubs the magwell.  Simply file the puckered area lightly with a handfile, a little at a time, testfitting as you go.  Then you can touchup the filed area by spraying with moly dry lube.

Mag too loose:  This is usually not a problem.  But if it is, use them with your lowers that have tight mag wells.

Thanks for the replys, I'll have to look at how the magazines fit in my lower.
Thanks!
mrf2

OK, so maybe this isn't a scientific answer.

I  generally find that the tightness is caused by feedlips that have spread a bit at the rear.  I apply a couple of SOFT taps to the rear feedlips with my tight magazine repair tool  - a soft rubber mallet.

Those tight mags loosen up every time.