Congrats on your "new" Interarms Mauser. I own one in 9mm, and really enjoy it. Also, welcome to the world of loading 30 Luger brass. It can be a challenge to find the right bullet, powder type, neck tension, and loading to make your Luger happy. Many of us on this forum load and shoot the 30 Luger cartridge.....some of us own other handguns in this caliber also.
I tried the fast powders initially, and got decent results, but not a 100% reliable end result, in my way of thinking. I am one of those folks that have been happy with using Unique powder in my 93gr bullet loads. I don't load many 85gr bullets anymore. I find that a full load of Unique, which is what is needed for my handguns to cycle reliably, is not a dirty load. The new Unique powder(formula) is a bit cleaner than the old stuff that I started with decades ago.
Basically one finds what one's Luger likes, and stick with it......and enjoy the ride in finding it!!
