There must be something there that peels lead from the first round and it builds from that.Definitely talk to S&W.
Good to know I'm not the only one. S&W still has not replied but will report back when they do.
Dear Customer,
That is normal lead build up after shooting non copper coated ammunition. We would recommend using a good cleaning solvent and brass brush to clean the lead out.
If further assistance is required please reply accordingly.
Sincerely,
Rob
Im sorry, but that is not typical lead build up. .22 projectiles should have some form of lube on them. In pistol-length barrels, you shouldn't have gone through the lube. In rifles, you'll often lead the last little bit of the bore with cheap ammo as the crappy lube job runs out. Good ammo, like wolf match or extra match, just doesn't lead since they've got pretty great lube on the bullet.
I'd be interested in completely de-leading it(being careful not to etch your barrel with chemical lead remover), and passing a bore scope up there to look for a chatter mark in the rifling, or even a crack. I'm also curious if the OP had a squib in the string of shots and fired behind the bore obstruction.
if you can find some, try some good eley or wolf match to see if it still leads up like that in the same spot. I've fired thousands through my sp22m3 in between cleanings and never experienced build-up like that.
That is a damn lie... I have never had a lead build up like that from any 22 ever regardless of coating...There is something wrong with their manufacturing process... I would suggest calling them in the morning as the help line people are much better than the e-mail support people.