I can go to the range with my Gen 2 or 4 Glock 19, the S&W .357 and Ruger .357, using ammo from Blazer, Remington, American Federal! The dirtiest of the group is the 7 shot S&W. That is shooting only 100 rds each.
So this post started 2 months ago... Any range report yet?
Seems like a few people didnt read and comprehend that you were going to be shooting the same brand ammo...And started talking about the ammo being the difference in why one is dirtier than the other.
I would have to say that the worst ones whould be do to excessive oil and when you do the test one person needs to oil each gun equally???