Forcing cone or cylinder issue with new 340M&P?

J

jdjimbo

Inactive
I'm trying to decide if this is a "send it into S&W" issue. Measuring the cylinder to barrel gap with shims:

-left side of forcing cone with cylinder held back firmly but not as hard as I can: .011" fits very easily, .012" shim fits tightly, .013" does not fit
-right side of forcing cone with cylinder held back firmly but not as hard as I can: .008" fits tightly, .009" the very edge slips in
-left side with cylinder held forward .004" tightly, .003" easily
-right side with cylinder held forward .0015" fits tightly

I measured with each chamber to make sure it wasn't just a part of the cylinder that was uneven. Same results for each chamber. I have had binding issues when shooting more than 50 rounds in one sitting.

Looks like end shake of .008" which is a lot. That combined with the uneven measurements has me thinking of sending this in to be checked out. Thoughts?
 
As you found, there is not enough barrel-cylinder gap. Most folks think the smaller the better, but too tight can mean binding when the cylinder warms up. Ideal is .007"; IMO, .003" is too small. Cylinder faces machined unevenly are not uncommon in all makes of revolvers.

I see no other problem worth worrying about, but you can call S&W; their CS is pretty good about keeping the customer happy and they might well have you return the gun on their dime.

Jim
 
If the left and right clearance is the same on every cylinder bore, the face of the cylinder is ok. The barrel end is out of square (unlikely) or the cylinder is cocked (likely). Send it back to S&W.
 
I had very similar bc gap measurements on a new Model 57 classic two months ago. The accuracy was so good that I was hesitant to call Smith's customer service. The uneven gap bothered me enough to call, though. The cs guy said it sounded like an "open cylinder gap" and to send it in. They put a new barrel on it and it now has a perfectly even .004" gap all the way around. Turn around time was ten days. I'm completely satisfied!
 
Thanks for the input. I've called S&W and they are sending me a FedEx label. If it was one or the other I'd work it myself, but I don't have the tools or skill to work barrel gap and endshake simultaneously.
 
You must log in or register to reply here.
Back
Top