I have two different P320sc grip modules. Can anyone tell me why they’re different in the marked areas? One is marked “S” and the other “S-S”

The second one is the updated version, notice the slightly extended beaver tail. SIG was replacing the first version with the second version when owners sent in their P320sc pistols for the trigger upgrade.

I cannot explain why SIG changed the highlighted areas.

Click the link, scroll down a bit and watch the video "Sig grip shell update".

https://osagecountyguns.com/fi...d-scr-943-m-blk.html

Not sure on the TDL, but IIRC the slide catch got revised & that's the reason for the difference there.

Thank you all for your replies, very informative!

Hmm... That's interesting. I sent a 320SC in for the upgrade, and it came back with the larger beavertail but the old-style slide catch. Back then the only grip frames that had slide catch changes were the full and the compact.

As toivo described, the photo is of two SC grip modules for the old-style slide catch, one with the original beavertail and the other with the longer beavertail to facilitate drop-testing the P320.