I have a "friend" who had a 22 semi auto with a little bit of a sticky chamber. What my "friend" did was to take about a postage stamp size piece of 0000 steel wool and put it through a patch loop on a cleaning rod (just like you would a regular cleaning patch). I, I mean my friend, wrapped the steel wool around the patch loop so that it looked sort of like a steel wool Q Tip. The end was then soaked in gun oil and the cleaning rod chucked into a cordless drill. The oil soaked steel wool was inserted into the chamber and rotated on low medium speed for 20-30 seconds. Since it is steel against steel (albeit soaked in oil) I was wondering if this could damage or in a sense "oversize" the chamber. The chamber didn't look any more polished than before this was done but rounds would "plop" in and out more easily. Just so I can let my friend know, is this method of cleaning a chamber too aggressive? I know an oversized chamber is not good and I wouldn't want my "friend" to damage any of his firearms.