r/P320

So I’m finally getting around to doing this mup1 and was hoping I haven’t screwed it up. Where the tip of the knife is I connected the holes but it is not a uniform oval. How much is that going to affect the function of the firearm? I didn’t want to keep going and make it too wide. Hopefully someone here has experience with these. Thank you

I retrofitted a Sig-Loc optic to a 2019 P320 X-Compact slide.

Keys to success (lol):

1. Ignore anything and everything Sig has to say about optic cuts and compatibility. They quietly have a billion different cuts as they tweak stuff in the background with zero official notice. My factory cut isn’t even on the website. Most egregiously, the banner for the compatibility guide has a picture of a cut that doesn’t exist in the guide.
2. Be precise on the measurements. The Sig-Loc sits tight between the front and rear of the cut. Almost no play. So little play I doubt you even need the two bosses. Tighter than any slip-on boss setup, if that makes sense. Pic of how tight a fit it was is in the post. No idea if that’s normal or just because the older slide cuts are a hair shorter. Who knows. Either way, this thing isn’t going anywhere. Plenty of surface fighting the shear, the optic body in the pocket and the two bosses. Digital caliper + drill press. My cut already had everything except the recesses for the bosses. Didn’t have another Sig-Loc P320 to measure off of, so I measured the bosses on the optic and transferred them. Found a helpful top-down pic that let me back into the X/Y and diameters.
3. Use a flat-bottom / Forstner-style bit in the drill press for the boss recesses. Link in the comments so this doesn’t get eaten.

Why did I do this? Like guns. Bored. I really like the optic and didn’t want the DPP version. The longer body looks better, and I got a fire deal on a brand new one that was ordered in error and never installed. Guess they didn’t have Sig-Loc after all.