I have a 686 model. When I shoot 357 mag it is very difficult to eject the spent shells. I was told that when 38s are shot they leave a carbon build up and you have to clean the chambers very well. And I did. I used a bronze and a ss brush (I used a 357, 410 and 45 sized brushes) attached to a drill. The chambers look to be very clean, but I am still having a problem. Any suggestions?

I'm assuming you aren't using hot handloads or one of the hyper boutique loads.

Chambers need polishing by a good gunsmith. This is a 20 minute job, for a smith who knows his craft.

By the way, I wouldn't use a stainless steel brush, only bronze.

I make sure I have no steel brushes anywhere around my bench when I am working with my revolvers. Even my scratch awls are brass.

I use a solvents to dissolve the build-up and then brass brushes -- all by hand. Power tools can do a lot of damage fast if you make a miscalculation.

Possibly the chambers left the factory a little bit on the rougher than desireable side, or maybe you roughed them up a little bit with the stainless steel brushes and power tools. As was mentioned it's better to let the solvents soak and do their job, than try to scour the crud out.
Try to find a gunsmith to examine the chambers. If you can't do that call Smith & Wesson, it might have to go back, although it might be best to exhaust all possibilities before doing that

Get rid of the Stainless Steel brushes. Do anything before you resort to that. Bronze brushes. Someone came up with the idea to use Chore Boy copper scrubbies wrapped around a bronze brush to get tough stuff like lead out. A few strand of copper wrapped around the bristles really toughens a bronze brush up.

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"He was kinda funny lookin'"

Which version 686?

Are all chambers equally hard to extract?

Is it leaving deep scratches in the brass?

Hard starting extraction, & then easy, or hard all the way out?

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Waiting for the break of day

What ammo are you shooting? Some of the steel cased and cheap imported ammo (Tulammo) has had this happen to other members.

As someone else mentioned: it could be that the pressure is too high. Are you shooting reloads? If so, pull the bullet on one of your cartridges and check the weight of the powder charge. You can't be too careful....

My 586-8 started that a few weeks ago. I used solvent and made sure the chambers were shiny clean. Eventually one chamber became so bad I had to pull the case out with my fingers.

This case had a bulge that lined up with the locking notch on the cylinder. I quit shooting it and called the S&W warranty smith here in Canada. Sent it to him last week and I haven't heard back from him yet.

I shoot 38 special Selliers and Bellot and the occasional 357. It has around 4000 rounds of 38 special through it.

I'm hoping it will be covered by warranty, if not, it will cost me around 250 Canadian for a replacement cylinder.

I bought this new 18 months ago and it has never had any +P through it.

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40 yrs Millwright Machinist