my bolt catch is starting to deform my lower. when it actually has a load on it from holding the bolt, it twists and the thumb pad pushes into the forward hump and the lower part that pushes on the bolt catch plunger jams against the lower. the lower is starting to deform at both locations.

Functionaly it works fine, always catches the bolt. The correct spring is installed. It just seems that either the lower has too much play in the slot where the bolt catch rides or my bolt catch is the problem. Has anyone seen this before and if so what is the fix? I thought about shimming the bc at the roll pin area to take up some of the slop?

I have not seen that. Does seem the slot it too wide or the BC is too narrow.
I will try and remmember to mic a couple when I get home.

may be time for a new roll pin for the mag catch lever.

I had it apart multiple times this weekend and the only thing that i did not check is if the roll pin fits snuggly into the bolt catch. The pin fits nice and tight into the lower and I use a punch to remove/replace it. Maybe the hole in the BC is oversized? That is alot of force on that pin though if that alone is supposed to stop the twist. There is a gap when the BC is in place and i can wobble it when there is no force on it. The BC came from a RRA lower kit.

I pulled out a Stag, DS, DPMS, and CMMG bolt catch. On all 4 the hole in the BC is .105"
The BC is .154" thick.

I measured CMMG, DPMS, Spikes lowers and all the slot is .156"

Pete

Are you dry firing the lower ?