ASM 1858 in 44, cylinder gap and hardcast

pomelum

pomelum

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i want to help someone that got a Armi San Marco, copy of a remington 1858, in 44.
wants to know how much cylinder gap is normal, and how much is too much.
he shot hard cast in the past and we wander what could have been, or is, the damage done.

for the owner of a 1858;
some part got a buggered up vertical slot cut into them, what is the purpose and is it normal?


will post pictures in a couple of days, dont have it in hands.

he just sent me an email, gap is about 1.76mm big.
 
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In David Chicoine's book 'Gunsmithing Guns of the Old West', he has a section on general revolver repair information. In that section he states that the barrel-to-cylinder gap 'is normally set by the gun factories to a tolerance of approximately four to eight thousandths of an inch.' A gap of 1.76 mm = 69 thou, more than 8 times the maximum gap. In my opinion, a fellow should NEVER shoot hard cast bullets in an antique revolver, as the impact into the forcing cone will slowly stretch the frame. I use pure lead bullets.
 
I will join the group at .004" gap from cylinder to barrel. When I first started shooting black powder I bought an italian kit copy of a colt navy. There was a typo in the instructions and gave a gap of .040" which is far to wide

cheers mooncoon
 
alright, i thought about jamming a 1cent (that will be cut to fit) between the cylinder and frame, to push the cyl forward.
it is a "O"? frame, going all around, so i guess it could have been worst. will need to re-preprofile the hammer too.
ill check about win 38-55 book, it looks like a gold mine.

as you people said, as of now its unshootable so ill tell him before he blow up.
 
With a whopping cylinder gap like that, it won't blow up (assuming the timing is still good), but he'll loose an awful lot of pressure once the base of the bullet leaves the cylinder. I've chrono'd the effect that large gaps have on velocity, and it will definitely result in a significantly lower muzzle velocity. Moving the cylinder forward is not that much help, as the head space will increase accordingly, resulting in lighter primer strikes or none at all.
 
we tried the 1cent trick i talked about, and re-profiled the hammer.
it worked for 6shot and then jammed, the 1cent (old one made of copper) was to soft and formed the shape of the canelures on the cyl.
will try with a 5cent in a couple of days.
 
If you are putting that coin in from the side, that is going to really increase the side to side wobble or slop. Every time you pull the trigger it is going to slam-twist the cylinder on the base pin. I would really urge you not to do that. Instead, the barrel should be turned in one or two turns to take up the gap. Then the forcing cone can be finished to give you a proper barrel to cylinder gap and headspace. This would be the proper way to fix it and you would then have a pistol that you could enjoy a long time. A decent gunsmith can do this for you. He will also have to shorten the ejector assembly to fit the slightly shorter barrel.
 
With a shim of that sort I'm amazed that the hand can reach forward enough to index the cylinder. At the same time check that the cylinder stop bolt is actually snapping into the stop notches correctly.

Personally with a gap that large I'd suggest that the gun be de-activated and turned into a wall hanger. If the frame stretched enough that you can fit a penny in between the cylinder and rear recoil shield then the metal is stretched far too much to trust it. Or if the fit of the cylinder is really that bad then I simply would not trust the gun just due to extremely poor quality control with the production of the parts and the obvious lack of any sort of educated inspection. But Armi San Marcos guns have a pretty good rep for quality so I'm guessing that he actually did manage to stretch the frame. Which means it may not be that far from blowing the entire frame apart.

I honestly can't imagine the frame stretching like that. At least not from black powder. He didn't load and shoot it with smokeless did he?
 
BCRider said:
I honestly can't imagine the frame stretching like that. At least not from black powder. He didn't load and shoot it with smokeless did he?
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The primary cause of a stretched frame boils down to three things: hardness of the bullet hitting the forcing cone, velocity of the bullet hitting the forcing cone, and the chamber pressure when the bullet hits the forcing cone. Of these three, I would say that the largest factor is bullet hardness. Smokeless powder can either reduce the impact on the forcing cone or increase it, depending upon the burn rate of the powder. Black powder used with a hard cast bullet will stretch the frame just as much as a medium speed smokeless powder will all other things being equal (hardness, velocity, brass used). A hard cast bullet will at least double the impact on the forcing cone compared to pure lead bullets or air cooled clip on wheel weight bullets. (i.e., frame will stretch twice as fast). BCRider has a good point about the stretched frame. I've seen a few antique pistols with stretched frames but NONE that were that bad. That pistol was seriously abused and it would not surprise me if the top strap failed through fatigue.
 
the gun passed a few hands, the owner shot only substitute (pyrodex and triple seven). he tried to overload it with 777 a couple of times to get more "power". i dont think it was him that stretched it so much. when he bought the gun it was basically like that. it is well worn out. he stored all the piece, except the frame, in an outdoor shed for a couple of years and it rusted good, the barrel is chromed but have deep scratch along the length of the grooves.

i cant understand how a "O"? frame can stretch so much as 1-2mm.
a couple of days ago i tried the same trick with a 99.99% nickel 25cent coin, it was still too soft for that. the triangular track on the cylinder printed on the coin basically only at one spot. i think the power is all directed in this small zone. sure the force is balanced on the cylinder rod, but its not much. i need to find a 1mm thick piece of hard steel.

i will post picture when i get it working properly. i cant work on it everyday, but as soon as i get my permit ill buy it from him.
 
Are you sure the frame has stretched as opposed to the barrel key being crushed? Also if you don't have access to a metal lathe so that you can set the barrel back, an alternative is to notch the bottom of the piece that the barrel screws into which will also set the barrel back. Second hand Italian revolvers are cheap enough that it is debatable whether having a gunsmith set the barrel back is economically wise. The barrel key has a slot milled down the center which the retaining screw fits into ; that makes it fairly easy to crush the barrel key and a cheap fix is to file a new one out of scrap metal without the slot. Depending on the dimensions of the hole in the cylinder pin for the barrel key, you might have to file that slot back a bit also

cheers mooncoon
 
The first thing I would do is center the cylinder notches over the bolt (cylinder lock) and see where the cylinder is in relation to the barrel and recoil shield. This will tell you whether shimming the cylinder forward, or moving the barrel back is a better option. If moving the cylinder ahead is what's called for I would be more inclined to counter bore the cylinder pin hole a bit and build a bushing that makes up the needed length.

jmo
 
here you go UPDATE:

the owner doesn't have a milling machine/metal lathe nor does i, so i did what i could. keep in mind that this gun is worth about 200-250$ new, so spending 300 on a gun smith is not a economically good idea. the metal square come from a "sawzal?" big reciprocating saw blade, made from hardened steel. tried copper and nickel and it hasn't worked so all or nothing. i dont know if he shot it yet, so if i dont update back it mean that all is alright.
first thing i did is check the timing and hands reach, it was all good and dandy. the only problem was the hammer shape, but after a good filing it was good. it's this gun last fix, the hand that rotate the cylinder reach just enough to turn it without problem, but if someone mistreat it again its good for the dumps.

i took pictures of the cyl and barrel for the people interested. you can see a little bit of the big scratches i talked about in the barrel. the cylinder have seen some abuse, some people got away with a screwdriver or something.

Rim6ZgU.jpg

SnMdHg6.jpg

zhUFGPm.jpg

SdK8quk.jpg

vafO6Pz.jpg


between, i dont know much about C&B revolvers where is the S/N on those? i wanted to edit the pictures but cant find it on either sides...
 
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I really hope it's just wide angle lens camera distortion but in the pictures the gun sure does look like the barrel is bent downwards a lot. And I'm not seeing any similar pincushion straight line distortion in the lines on the targets. That in combination with the need for a massive shim of this sort would confirm that the frame has stretched a lot. If it has then that would explain both the barrel angle AND the need for this big a shim to reduce the cylinder movement and close up the cylinder to barrel gap.

I'd have your buddy look carefully at new Remington clone pictures and also lay a ruler along the top of the frame. The top flat of the barrel and the top of the frame should be parallel to each other. If the barrel is angled down like the pictures suggest I'd call it a day and turn that gun into a wall hanger or desk lamp. If I'm right and the strap has stretched then I would not trust it even with lighter black powder loads.
 
If it is bent beyond repair, I will give you 200 for all the parts of it. He can then turn the barrelled frame in to get the registration cancelled.
 
i sent him an email, will take more picture tonight.
i looked at it for some time when i was fixing it and i think its just a Camera effect. will see.
 
fraserdw said:
If it is bent beyond repair, I will give you 200 for all the parts of it. He can then turn the barrelled frame in to get the registration cancelled.
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That's a very generous offer (I don't see any value in that gun).
Better take it and run.

Start the car, start the car..... :)
 
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