Have been building my first 365 from parts and just got around to assembling some of it last night.

Put the (factory) mag catch in the Wilson grip module and it is unbelievably stiff. As in I've never felt a mag release so stiff and with such limited travel. I don't think I could actuate the mag release without really breaking my grip.

Problem is, I don't actually have any mags yet to test the functionality of the mag catch, nor do I have any real experience on a 365 to compare (aside from a few rounds through a buddy's).

Is this normal with a Wilson grip module?

I mean…..they are stiff, but not horribly so. Get a mag and try would be my best advice.

When I first put mine in I thought I must have done something wrong as it was so stiff. I took it back apart and looked it over. Couldn't see how I could have put it together wrong. So put it together again. It was still stiff. Now after several months i dont even notice it.

Have no idea about the P365. I do have a P320C 9mm Wilson Carry Grip Module. This may help:

1) The Wilson P320 & P365 Grip Modules ship with: "Factory SIG-SAUER magazine release, spring, and lock included"
2) Since it is a SIG OEM, yours shouldn't be any different. Are you using a mag catch from Wilson or an existing Sig OEM Grip Module?

My Wilson Carry P320C Grip Module:
1) Mag catch pressure same as Sig OEM Grip Modules.
2) No real difference in pressure with or without mag. Can feel catch disengaging, of course.

Try lubing it and/or contact Wilson CS.