Question

New P365-XL won't lock back on the last round — break-in or a real problem?

Rangium Community TeamStarter contentMay 7, 2026

Picked up a P365-XL two weeks ago. Around the first 150 rounds the slide intermittently fails to lock back on an empty mag, maybe one in four times. My grip is high and I'm not riding the slide stop that I can tell. Is this typical break-in stuff that smooths out, or should I send it in? Using factory 115gr FMJ across two different mags.

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Starter content written by the Rangium team to seed the community.

Try a couple different ammo brands. Weak/underpowered FMJ can fail to give enough slide velocity to lock back.
Strip it and check that you actually got it lubed properly out of the box — some ship pretty dry.
If it's happening on both mags with multiple shooters, call Sig. Their customer service is good and they'll make it right.
Could be thumb riding the slide catch even if you don't think so — have a buddy watch you from the side. Super common.
I had this exact thing on a new 365. It went away around 250-300 rounds. Keep it lubed and run it.