It is doing exactly that. I have been traveling for a bit so I'm finally home with the gun at my workshop and a good magnifying glassOriginally Posted by OlongJohnson
It is doing exactly that. I have been traveling for a bit so I'm finally home with the gun at my workshop and a good magnifying glass
Just adding this to note that the cylinder stop spring on my M&P 340 was mis-installed the first time I opened it up, which was after the incompetent gun plumbers in S&W's warranty shop replaced the yoke. The spring was bent 90 degrees with the end that should have borne against the frame pointing toward the side plate. Basically, it appeared that the plumber just pushed the stop into place over the pin with the spring in the stop, and didn't take any care about making sure the spring was actually seated/positioned the way it was supposed to be. Kinda amazing it worked at all. Fortunately, the spring did not appear to have been damaged at all.
ETA: I've posted before that if I ever start in CAS, I'm hoping the name "Skip Chambers" isn't already taken.
Last edited by OlongJohnson; 10-05-2021 at 02:09 PM.
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Not another dime.
Several years ago when the USPSA guys were running 625s hard, the skip chambers thing came up. It had to do with the cylinder stop wearing and the bolt notches peening. You might find some info on Enos back before everybody switched to 8 shooters. Mike Carmoney and some others were working on it.
I have always wondered if the -2 modification to delete the cylinder stop screw and plunger and just assemble by cramming the spring into a recess might not have contributed to skipping.
Code Name: JET STREAM
Do the 8 shot.357 not do that? Do 6 Rd k/l frames ever do that?
All revolvers can do it, if the action is worked fast enough that the cylinder turns faster then the spring that powers the cylinder stop can work. Just some designs are better at engaging the cylinder stop earlier with more mechanical force. But those designs tend to have heavier trigger pulls.
It's why reducing the weight of the rotating mass (i.e. using a Ti cylinder) is a popular choice in competition guns. It's not only easier to turn that mass with less force, it's easier to stop it at the right time too.
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One advantage if the oval/rounded notches on the cylinder is it reduces peening by spreading the force more uniformly across the notch and stop and eliminating sharp edge stress points. Downside is, it reduces the notch engagement surface.
It wouldn't surprise me if it turns out that the cylinder stop spring needs to be replace regularly versus designs with a square/rectangular lockup. I bet picking the brain of a GIGN Armorer would be insightful.
I have read those threads! They were very useful to me a few years ago diagnosing a fucking wrecked 627
As I remember, it was mostly 625s. The bigger, heavier cylinder was some of the cause I think. Some were carrying spare bolts and springs to matches. Some changed to titanium cylinders. I don't remember everything.
I just went to Enos and did a search. I didn't find what I was looking for but found a post about a 929 that was skipping chambers.
Competition shooters get the cyclic rate up pretty high.
Word has it that the next shipment of 4” guns is quite delayed.
#RESIST
Update: it was definitely the cylinder stop. See below for photo of the old cylinder stop side by side with the replacement that Chapuis sent me.
The damaged stop on the right has developed a rounded edge where it interfaces with the cylinder notches, which is likely why it was skipping past cylinders in fast double action fire. What's interesting is I also noticed minute deformation on the cylinder notches themselves, which I'm going to keep an eye on.
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