I had a few questions for the Sig P220 10mm owners here…

Can you or have you shot 40cal/40s&w ammo through your sig 10mm? Any issues?

Are the 10mm mags for the P220 just 45acp mags with a modified mag lip?

I don't own one but you can see the differences in the magazines on the sig website.

https://www.sigsauer.com/magaz...tols.html?model=1609

It will usually work, but you'll be relying on the extractor to hold the shorter .40 S&W to the breech face; you won't be headspacing on the case mouth.

Some say it's OK, some say it's dangerous. I like to err on the safe side of things with my guns and won't do it.

I would not shoot .40s through it but that is just me.
I use 220 .45 ACT mags with zero issues.

https://gregcotellc.com/cart/s...458-44522-p-543.html

I have on occasion and had zero issues. As to is it safe? That is up to you to decide.

It seems like you risk the possibility of catching the lip where the 10mm case mouth would headspace. Short jump so maybe low probability. IDK...

I wouldn't put this in the same class as shooting 38s out of a 357, where in both cases the barrel is set up to accept a bullet making the jump.

The 10mm mags have a rib that slightly narrows the inside of the mag vs the 45. But given Black's experience, I might try some factory 10 round 45 mags to see if they work OK.

At the end, you're still putting ammunition through a barrel that it wasn't chambered for, so if anything goes wrong, it's on you. Your call on the risk/benefit...

I never tried the 10 rounders only the 8 rounders. I think folks may have had some issues with the 10 rounders if I recall correctly.