This might seem ridiculous to some here, but It shows it's ugly head on "some" Stainless 10mm 1911's.
Galling becomes a problem between slide and frame on some brands when they are new. Stainless on stainless galling is real. Use a good lubricate on the rails until the gun gets a good break-in. If it's bad, you might even have to use RIG gun grease for awhile on the rails. A little goes a long way. Especially in cold weather.
As 79S stated for the other problem your having. The plunk test is good to test your handloads. Also using the Lee Factory Crimp Die is good advise.
