I have somewhat of a problem with light loads in my .45 Colt Marlin Cowboy rifle. I get gas blowing back into my face a good bit. I have used 6 grains of Trail Boss with 200 grain bullets and 5 grains of TB with 250 grain bullets. Those are about 1/2 grain off maximum loads. They shoot well, but I get blowback and the cases come out black and sooty. I have also used 8 grains of Unique behind a 255 grain bullet and have not had any blowback. The load with Unique , however, has a little more power than I would like for Cowboy shooting. What loads do you folks use in your .45 Colt rifles? Have you ever experienced blowback with your rifle? Is it possible that my Marlin has an oversize chamber? I generally use Starline brass but also have Remington and Winchester cases. Any suggestions are appreciated.
