I recently picked up a IWI Galil Ace rifle in 556. Took it to the range and shot 200 rounds with 1 malfunction (gun basically stovepiped a live round when attempting to chamber it).
However when handling the weapon afterwards I noticed an interesting phenomenon. If I insert an empty Lancer AWM, I noticed a slight amount of front-to-back play in the magwell. If I push the mag to the rear (towards the trigger guard) with very minor force (one finger), the rear of the follower will slip past, and over top of, the bolt catch. As a result, if the bolt is closed, you cant pull it to the rear. If it's locked to the rear, you can't release it to go into battery. Pushing the mag forward again (or just pressing the mag release and dropping it) results in the follower slipping back underneath the bolt catch, and then the rifle functions normally.
This also happens with the Magpul D60, however no pushing/pulling of the mag is necessary. It does it 100% of the time. If there is an empty D60 in the gun, you can not work the bolt.
Standard PMAGS don't seem to have this issue at all. Nor do USGI style mags.
I haven't had any issues when firing. It only happens with empty mags, so I'm not sure its much of an issue. Perhaps just a slightly out of spec bolt catch? Or is a bit of mag sensitivity just an inherent part of the design?
Just curious if anyone else has noticed anything similar?