So I sprung for one of these a few years back when they hit the market and, overall, love the rifle. I'm one of these weirdos who doesn't care much that it takes a proprietary mag. In fact, that was part of what made the decision for me as I wanted one as close to the Swiss-made 551 as I could get. I've got many different types of rifles including AR's and AK's, so the AK-style release is somewhat natural to me anyway.
So there is a roll pin that fits the mag/thumb release to the bottom receiver. It's the roll pin that the mag release obviously rotates on. I didn't have any problem for the first few years but, lately, the roll pin seems to have been coming loose. After a few mags it tends to have a lateral movement and unseat itself. When it does, it leaves the release somewhat to the rear and doesn't allow the mag to seat itself. I have to use a punch and something to lightly tap it in order for it to fit back into its proper position. Upon close inspection, it seems the roll pin isn't quite long enough to fit flush with both sides of the receiver. If that were the case, it likely wouldn't have that effect.
Anyone else experience this problem? If so, is there a part available from SIG that would rectify this i.e. a new roll pin. I've removed mine and tried to widen it some with hand tools but the tightness of it seems to be less of an issue than the fact that it seems to be a millimeter or two too short. I haven't contacted SIG yet but likely will soon. Any weigh-in would be appreciated.