I have a new 625-8PC that I noticed the barrel forcing cone gets a noticeable carbon build up from about 5 o'clock around to about 7 o'clock. I do not have any lead fowling in the barrel. I shoot light target loads with coated 200gn lswc.

The gun is not a tack driver for me as it groups about 4" @ 25 yards, with my forearms resting on a sandbag.

I inspected some of my other revolvers and noticed the forcing cones had an even appearance all the way around.

I have tried using factory fmj ammo too and the carbon build up is the same.

Any thoughts???

I have a 625 JM. Shooting lead always produced quite a bit of leading. Went back to Berrys plated, and pretty darn clean. One thing that I did before I switched back is clean the barrel with a bronze 20 ga. shotgun brush. Makes quick work of cleaning. Bob

The issue is Not lead deposits, it is a carbon build up of about 1/32" on the bottom of the forcing cone before the rifling starts.

What's the load. on 2nd thought, if your only getting 4" groups, I'd check the parallelism of the forcing cone to the cylinder face. I might be a large variation that is allowing blowbye

Just bite the bullet and send her back to the mothership. Four inch accuracy and build up is not a S&W much less a PC S&W.

Thanks for the replies.
How can I check the barrel to see if it's parallel to the cylinder? I do know the b/c gap is .006 when I check it on both the left & right sides.

I will call the Mothership after Christmas but was wondering if this was a real concern first.