MODEL 617 CYLINDER AND TRIGGER LOCKING UP

[armorer951]

Have you checked the fired casings for evidence of swelling or distortion of the rear of the casing, in the area of the firing pin impact? Will a fired casing from the gun stand straight up when placed on it's base on a flat surface?

And the cylinder rotates freely/open and closes normally when fully loaded with live rounds? (not during firing, just rotation when loaded)

Sounds like the fired casings are dragging on the breechface for some reason.

 

[Protocall_Design]

Look for firing pin dings on the back of the chambers. When this happens, it's caused by dry firing a rimfire gun. The unfired cases may be able to move freely, but after firing, get caught on the small burr on the back edge of the chamber. The remedy is to carefully file off the burr or run a chamber reamer to cut off the burr.

 

[sdk]

There are no firing pin dings on the back of the chambers and the spent rounds appear to be normal around where the firing pin strikes it. I have an unfired round with scrape marks on the head which tells me that unfired rounds are backing out and binding up against the recoil shield. Spent rounds may also be doing this but I'm not sure. I'm hoping to do some more shooting with this gun next weekend.
S.K.

 

[Tom S.]

Have you measured the cylinder to back plate gap to make sure it's even and the back plate isn't bent or the cylinder crooked?

 

[sdk]

Headspace is about .010. I believe that rounds (probably unfired) are backing out of the cylinder and binding up against the recoil shield. I'll be working more with it this weekend. Thanks.
S.K.

 

[armorer951]

I believe you mentioned that live rounds freely drop into, and fall out of the cylinder. If this is the case, the live rounds are not "binding" during firing.

Remove the yoke screw (front sideplate) and check the headspace (rear clyinder gauge) with the screw removed.

 

[sdk]

I will do that. However, as I stated earlier, I have a live round that was in the gun during a bind up and there are obvious scrape marks on the head. The other rounds in the cylinder during the bind up (both live and spent) had no such marks. Also, when shining a flashlight into the opposite side of the gun during a bind up, I can see definite clearance between the back of the cylinder and the recoil shield but I can also see an obstruction of that clearance on the lower portion of the cylinder which I believe is a round butted up against the recoil shield. Thanks again.
S.K.

 

[armorer951]

There are no forces at work during firing that would drive a live round to the rear, and against the breechface.

 

[sdk]

Yes, but simple movement of the gun will or could cause one or more live rounds to slide back. After about 60 shots are fired the binding stops. I attribute this to the charge hole getting dirty thus holding the rounds more firmly. Of course the cylinder getting hotter may also help prevent the rounds from sliding back so easily. Thanks for lending your expertise.
S.K.

 

[lscocoa]

Have you checked the fired casings for evidence of swelling or distortion of the rear of the casing, in the area of the firing pin impact? Will a fired casing from the gun stand straight up when placed on it's base on a flat surface?

And the cylinder rotates freely/open and closes normally when fully loaded with live rounds? (not during firing, just rotation when loaded)

Sounds like the fired casings are dragging on the breechface for some reason.

I had similar problems with cci and Remington bulk ammo . I found three chambers in a m-317 would consistently bulge ammo at the rim pushing the round back. I took one round and fired it left the empty in and chambered another round next to it and fired . If it backed out I marked the chamber pulled the shell and moved on to the next and so on still all were checked . Federal ,Winchester and eley never dragged . I have a 617 that dragged with that CCI " shootem ammo" . S&W replaced the 317's cylinder after I emailed them.

 

[Wee Hooker]

Man this is getting interesting. I would love to get my hands on this gun for testing/ diagnosis.

ps, have you tried 22 shorts/cb caps. IF these run, I'm thinking it would point to your issue likely the relationship of with cartridge /chamber length.

 

[H Richard]

How do you eject the fired rounds? Ejecting them with the barrel pointing forward of at an angle could be dumping powder residue behind the extractor star. Always eject the empties with the barrel pointed straight up. Good luck.

 

[stinga]

FWIW.... I just joined this site in an effort to find more detail about my M617 issue. The exact same issue... With my 6"617 no dash. I sent it in for service more than a week ago and I will let you know what or if they find anything. It will be interesting for sure to see if I get the same response from Smith.

 

[sdk]

Last week I applied some blank ink to the recoil shield with a sharpie and fired some rounds. As a result there were some distinct rub marks in the inked surface that proves that unseated rounds were rubbing against the recoil shield. Surprisingly, the ink seemed to reduce the binding, probably by reducing the friction between the recoil shield and the round. My next step was to remove the cylinder and yoke from the gun and polish the recoil shield using a Dremel and a polishing bit that came with the Dremel. I then went to the range and fired off 100 rounds without any binding. The following day I went back to the range and shot another 100 rounds without any binding and a couple days later fired another 100 rounds with no binding. It appears that the problem is corrected. Thanks for all the input.
S.K.