You could buy a go and a no-go gauge.
However I will bet $$$ that you just need to bump your shoulder back a touch and just be sure the base of the case gets fully resized. I only say that as I have seen people have the same fits with gas guns before.
The offer to use my body die and case gauge still stands. Or, PM your address and I will send you some GI brass that I have run through my 1050.