Is the P365 9mm & the .380 slide interchangeable?

My guess would be no. Although they use the same diameter bullets, the .380 ACP's diameter at the rim is much smaller than the 9mm, so the slide breech face dimensions would necessarily be different.

It's the same FCU. The slides and grips are interchangeable. The barrels are probably not between slides but you could swap a 9mm slide with a 380 slide on the same frame and FCU and it would work.

The slides are different. The .380 model is less tall and has relief cuts to lighten the weight.

I own both models.

If you’re wondering about holster compatibility, my .380 365 does work in my kydex 365 9mm holster but the fit isn’t as snug due to the slide height difference.

quote:

Originally posted by Lwt16:
The slides are different...

quote:

Originally posted by DaBigBR:
It's the same FCU. The slides and grips are interchangeable. The barrels are probably not between slides but you could swap a 9mm slide with a 380 slide on the same frame and FCU and it would work.

What they said. If you swap entire upper assemblies, no problem. But, if you just want to swap barrels or just the slides, then no bueno.

Thanks for all the input.