1911A1, advice needed.

In my experience the problem you detailed could be due to the ammunition.  I shot IPSC for years with a bone stock surplus 1911A1 using both reloads and factory ammo.  I never had any problems with the slide returning fully to battery with factory 230 gr, ball but did with the 200 gr. SWC handloads I often used.  I fixed the problem by polishing the feed ramp and testing every cartridge by removing the barrel and dropping each round into the chamber.  Any that sat proud were broken down and reloaded. The barrel was cold, of course and the rounds might have slid further down in a hot barrel.

I’m not that familiar with the 1911, but this problem sounds similar to what I experienced before when reloading cases that were fired in some pistol chambers that did not fully support the case just forward of the solid head (usually because of the feed ramp). I overcame this by using the LEE taper crimp die which incorporates a carbide ring at the bottom of the die, this removed the slight “bulge” which sometimes prevented the slide from going fully forward.