Remington ammo does NOT feed reliably in my p-1. I looked up the problem online and apparently it is a common problem with these pistols. The ammo I had came in a huge yellow box.
I’m not sure if this was an issue with the p-38 as well
The OAL of the Remington is different (I can't remember which way) and that causes feed problems.
Winchester White Box is the typical go-to (aside from the batch that got recalled I guess).
MagTech / Blazer 115gr FMJ should be fine as well.
If you want to make it a lot more robust, install a late post-war "fat" slide and forged block.
It can be challenging (but fun) to track down all the parts though.