As expected, the straight lead rounds are dirtier then the TMJ rounds. I shoot it through my KRISS as well and find a lot more "smoke" when it goes bang. I clean after every visit and find a lot of grit in the action.
It's a great round though and has never let me down.
25 yard is not long range!
At both ranges I have been to there is a strict rule about not shooting pistols past 25 yards. One staff member at one range said it was the legal maximum for pistols in Ontario; no idea on the validity of that.