Howdy Paladin,
Mag Tech Brass? I have a Chinese made TTN 1878 Coach gun that I use with mag tech brass 12 guage. Occasionally, one or two things happens to the brass. If it gets out of round, it becomes a pain and is hard to slide out easily. Such as, accidently gets stepped on while transitioning to the next position. It can be fixed, but is a real pain in the neck to do.
I've also found the if I get in a hurry loading up, I get a little sloppy with the glue on the over shot wad, and it spills over, to the outside. Not noticable going in, but sticky coming out.............