I recently traded a USGI mag for a Orlite on EE. The previous owner who had the Orlite said it wouldn't lock into his rifle due to the rib hitting the bottm of the mag well. When I inserted the mag it fit in perfectly. The mold number is 1/4.

I read in the mag faq that low mold numbers won't function in ARs due to the beveling on the mag well, but it was fine on mine.

Does this sometimes happen with Orlites? It was a unmodified mag.

Thanks
The Cheat

I remember reading somewhere that there are different lots of Orlite mags.  When I bought some of mine the guy selling them said that he had returned some and got back mags starting with a certain serial number because they would fit in Bushmaster rifles with no modification needed.  

The whole issue revolves around the fact that most of the aftermarket makers of lower recievers don't chamfer the bottom of the mag well as deeply as Colt, and the Orlites (early and late) tend to have this problem w/non Colt lowers. Thermolds also have the problem, tho usually to a lesser extent.

When I was using Orlites, I just just shaved the top of the rib slightly until they'd fit into my Rock River lower, since the RR unit was the worst in this respect. When I converted over to Thermolds, I had to do the same thing, but to a lesser extent.

BTW, just acquired a new Rock River lower a couple of weeks ago, and the chamfer on the mag well is much deeper than on my older unit, so maybe RR has gotten the message about the plastic mag problem [:D]