Revolver cylinder problem

[Ganderite]

I lubed the cylinder catch as suggested and gun now locks up nice and tight. i shot it again last night and found that 4/6 go in the black (20 yards) and 2 go in the white. One high right and one low right. Each time I shoot a cylinder of shots, one more round appears high and low right. After 4 cylinders of shots, there was a nice pair of clusters of rounds, high and low right.

I am assuming that one chamber shoots high right and one shoots low right. I bought this S&W M19 used, cheap. It appears to have been shot a lot. other than the two flyers per cyninder, it is a nice piece.

With the culynder open, when I spin it, I see no wobble of the cylinder, but I do see a slight wobble of the tip of the ejector rod.

Help!

 

[colinjw]

It could be that there are 2 chambers that do not line up properly with the barrel causing the bullet to shoot to a different point of impact.

Have you checked to see if it is the same 2 chambers all the time ?

 

[Ganderite]

Each time i shoot, I get 2 shots out of the group, at the same places. After 4 cylinders there were a pair of cloverleaf groups, out of the group. I have to assume it is the same two chambers causing the fliers.

 

[BCRider]

Because there is a forcing cone to funnel the bullet into the barrel there would need to be something significant happening back at the chamber to cone gap that is greatly distorting the bullets as they transition to the barrel. Since all the bullets are going down the same barrel and 4 of them are printing well on the target it suggests that the other two are receiving some significant but repeatable damage that is resulting in them consistently leaving the barrel with a kick that pushes them to the upper and lower right.

I would suggest that a good first step is to straighten that ejector pin if it's out by any sort of significant amount. After all, the pin plays a part in the cylinder alignment since it locks into the forward catch to provide support.

A few thou wobble in the extractor pin isn't anything to worry about. But if the center point is running around in a circle that is more than about 1/32 inch I'd want to work at straightening it up. And the fact that you say you can see the wobble suggest to me that it's worth the trouble to correct. A bent pin will actually lever the cylinder out of alignment as it rotates around. This could be the cause of the two most affected chambers that line up with the peak and valley of the bend.

But that's a fussy bit of work that is best done with a set of V blocks and a dial guage to check for the exact location of the bend so you know where to put the correction force. Otherwise you could well end up correcting the first bend by adding a second bend beside it. Then you'd have an S shaped pin which isn't helping the cause much at all. Again this is some fussy work best left to a smith or at least a decently talented home shop machinist with the right gear and decent analytical thought processes.

With that done if it's still shooting way off on two chambers a good second step would be to determine which two chambers are the bad ones. A felt marker or labels can be used to number the chambers in a way that you can identify which one is being shot from the outside. Then test fire again to find out which two are the bad ones. Just degrease the cylinder first so they markings don't rub or fall off since you'll need them there for the duration of all the testing and repairs.

Once you've identified the trouble chambers the goal is to find what is different about those two compared to the others.

To find out if the bullets are being badly shaved you can hold sheets of paper to either side and see if there's a significant amout of lead spray. Somehow set up something to hold big sheets of paper about 10 to 12 inches to either side of the gun while you shoot. Then as you shoot each chamber move forward or back about 4 inches between shots. This will imprint a line for each chamber so you can see which chambers are spraying more material than the others. Obviously keep track of the chamber numbering during this test. This will quickly test for a significant shearing off of lead from the bullets. And if you're shooting jacketed it would be worth finding some lead bullets for this particular test.

Another test is to see if the chambers line up with the barrel to within a good tolerance. But this would require a good fitting, non wobbling long brass or aluminium plug that you can put down the barrel and see if it lines up smoothly with the cylinder chambers. Some folks say that they can see misalignment by shining a flashlight into the joint between the cylinder and the recoil shield and looking down from the barrel. But when I tried this I couldn't see anything that meant anything yet I knew I had some misalignment due to loose timing on my gun. But then being new I didn't know exactily what to look for. So I made myself a brass plug which soon told me what was going on. You'd need someone with a lathe to make such a thing in a way that is accurate enough to use with confidence.

Another thing to check once you know which chambers are the flyers is the cylinder stop notches that provide the lockup for those two chambers. Are they noticably more peened out than the others? If so the notches will not hold those chambers in proper alignment.

I'd also want to look at the mouths of the chambers to see if they've become oval shaped at all. If they don't line up well with the forcing cone they may have become battered into an oval shape over time. You'll need something like a digital or dial caliper to check for the few thou of distortion that would result. It won't be anything you could see with the naked eye. Or if you CAN see it then it's really bad and it would imply that the cylinder is toast.

That's about all that my home shop gunsmithing skills tell me to check. Likely at least one of those things will turn up an issue or two that will then need to be evaluated to figure out if it's fixable and how to do it. I hope it's something inexpensive. The 19 is a fantastic wheelgun and I'd hate to hear that yours is beyond economical repair. Start with straightening the pin so there's nothing at all out of alignment in the cylinder crane assembly and work from there.

 

[Ganderite]

"Again this is some fussy work best left to a smith or at least a decently talented home shop machinist with the right gear and decent analytical thought processes. "

Well, that rules me out!

I do have the impression that some chambers are blasting lead out the side. I will number them and repeat the grouping test and check for lead shaving, too.

This will give me the hard info to present to the smith.

Thanks.

 

[Ganderite]

I numbered the cylinders. As it happens, I had to test two types of new handloads in 38 Spl, so I inlcuded the M19 in that test with my other 38/357 guns.

As I fired each shot, I plotted it on a target. After 12 shots (6 of each type), if found:

- Each chamber shot to a different location ( but similar for each type of ammo. i.e. #1 was always high right and #2 was always ar 12 o'clock.

- All 12 were in the black of a NRA bullseye target at 20 yards.

Since that is god enoughfor a non-competition gun, I will live with it.

Thanks for your help.

 

[BCRider]

And here I thought it was a BIG problem If it's hitting in different portions of the bullseye then things can't be so bad after all. But still, if you find yourself with a little extra cash and if the ejector is wobbling by an easily visible amount it would sharpen things up to have it straightened to a tighter tolerance. But from what you're saying now it's not a critical situation.