By viewer request, here are up close images of the SIG 551 aftermarket trigger. No, it’s not a drop-in cartridge like some of the modern AR designs.
But is really only consists of 2 parts: sear & hammer. The trick is putting the springs back in after taking the OEM out. I suggest you take photos and look at some of our posts on the subject for best practices.
We don’t include a detailed install, but we do cover the stuff that may not seem obvious to the weekend warrior.
“Shooting Guns & Having Fun”