Honestly - eliminate the Remington ammo and try it again. I have seen a LOT of complaints about malfunctioning semi autos of various makes over the past year - using Remington ammo. Their target ammo is under powered. One guy even paid a local gunsmith to solve the issue instead of paying to ship his pistol back to the factory. The diagnosis - the UMC ammo.
It may not be that. But I'd clean and lube the gun, and try a different brand of target ammo