I have a P220 Carry .45ACP that has a fail to return to battery about 2 or 3 times per 100 rds. Not much, sometimes I can smack it shut with my hand. Doesn't matter what brand ammo or type. FMJ or HP. It is a 2017 model I bought new. Here is what I've done. Replaced the recoil spring. Didn't make any difference. Switched barrels with another P220 Carry barrel I had. No difference. I've been shooting for more than 35 years and am not limp wristing. Is it possible that the extractor could cause this? I really don't want to send this back to Sig. Thanks for your suggestions.

Check everything in the feed path for burrs or an irregularity. I am presuming the pistol is properly lubed.

Extractor, breech face, etc. Had a similar problem with a P226 .22LR conversion unit once. De-burred the extractor and the barrel cutout for the extractor. Also slightly modified the extractor shape, which I would not recommend you do. Functions fine now.

Place the bare slide on the frame and manually move it fore/aft. See if there is any binding or undue friction. Not the same as with the barrel/mainspring in place, but may tell you something.

Finally, any pattern on rounds fired before it occurs? Like heat-related expansion after firing x number of rounds.

If there is nothing obvious, it's probably got to go back to Sig. Good luck.

I would suspect improper cleaning and/or lubing.

Sigs like to be run wet.

I was a police armorer since 1998 and our agency carried the P220ST .45 cal. for years. Number 1 problem I encountered with malfunctions was the locking block. Never found anything visibly wrong, but each time I would go to the range and do a parts swap out, the problem stopped when I dropped in a new locking block. I then would take the bad locking block and put it in a good pistol and it would start having the same problem. Not sure if this helps you, but something you might consider checking. Good luck.

I got the slide totally disassembled. The extractor, firing pin and locking block had heavy grease on them. (not from me). Also, the locking block had a fair bit of metal shavings on it. I will replace that. Thanks USMC2PD. I gave everything a thorough cleaning and put a fairly heavy dose of lube on the rails and outside of barrel.

Glad to be of service. I hope your situation is corrected. I bought my P220ST when we switched to the Sig 320. It still shoots great. Good luck and good shooting!

I wonder if you could answer this. Top Gun has the safety lock for 14.95. Midwest Gun works has it with the Sig "super finish" for 30.50. Is there really any difference?