Originally Posted by 6string

This is a more common problem than you'd think, especially with 9 mm.
Your pistol, like most 1911 types, very likely has an unsupported chamber right at the feed ramp. So, your fired cases come out oversized at the base, especially with warmer loads.
The next problem with carbide dies is that, due to the brittle nature of the carbide, they cannot be allowed to hit the shell holder. So, that rear oversized base is left unsized.

Nothing is broken or out of spec. You just have an unfortunate combination of circumstances.
Your best option is to get a plain old all-steel non-carbide sizing die. These are cut to match the taper of the cartridge according to SAAMI specifications.
Of course, you'll have to lube your cases.
On the up-side, you'll get ammo that generally is, according to statistical evidence, more accurate.

I've found that 9mm all steel dies by RCBS and Redding to hold true to SAAMI specs, be propery heat treated for long life, and nicely polished for ease of use.

In any case, opening up the chamber of your pistol will just make matters worse.

I hope this helps,
Jim