BTW, this is a Hahn bottom loading mag block I’m modifying….but should be similar process for most mag blocks.
Picture below shows how high my ears are after grinding.
Modify mag catch for unmodified Colt mags. I initially started at about .040″ which cleared but was having malfunctions when firing as I think the mags were moving and rubbing on the carrier. You can see i’m close to .100″ now. I think if I were to do it over, I would start testing around .060 – .080 now….but what I have now is working so I’ll leave it alone.
Removing more material from the mag catch required the feed ramps to be deepened on my Hahn mag block. I happen to be using an MGI lower and a 556 mag well with Hahn block that has always been a little small for this magwell which I remedied years ago by bolting the mag block in place.
Lastly, since the mag catch was lowered, I lost bolt hold open functionality. Little TIG welding underneath the ‘tab’ fixed that.