To ream or not to ream

[Misfire99]

Hi All
One of my 1858 Remingtons is made by Armi San Marco. It isn't the most accurate pistol in the world. I just did a little measuring of the cylinder and the bore. The Cylinder is .450" and the bore is .459". This doesn't lend itself to good accuracy. I also have a Pietta 1858 buffalo Remington. The cylinder on the Pietta micks out at .447" and the bore at .404". When I am taking these measurements I am using a caliper. I use the endside part of the caliper to measure both the cylinder and the bore. I know That this is not a good way to measure a rifled bore but it does give me some idea of whats what.

I was thinking that I could ream the ASM cylinder to .456" This would allow me to use a .457" ball and bring me much closer to bore size. I know that this is trying to make a silk purse out of a sows ear but this gun just screams out for something to be done to make it shoot better. What do you all think?


News Flash

A .456 reamer is a non standard size. I have been looking on line for one and after much unfruitful searching I see I would have to have a reamer made and now the price just went from about $8 to more then the revolver is worth. So this is a dead idea.

 

[Marlin 45 carbine]

You measured the bore of the Pietta '58 at .404? misprint on that? I have that same revolver, mine shoots Ok but I've considered having a reamer made (a buddy is tool and die shop sharpener) and offering a service to ream to size and deepen for more powder charge BP revolver cylinders. Big Iron was doing this but chintzed lots of fellers and got into trouble.
I'm thinking there is lilely a market for this type work. BP revolvers seem to be gaining in popularity, also derringer-type pistols

 

[Jamie C.]

If the bore is .459 then I'm not seeing where reaming the cylinder to less than that is going to gain you much anyway.

.460, at minimum, would seem to be the way to go if you were going to bother at all.


J.C.

 

[Bad Flynch]

Please humor an insufferable idiot, but when you say bore, do you mean the bore or the groove diameter? It would make a real difference, you know.

When performing these critical measurements, it is customary to distinguish between the two and use exact terminology. In addition, it is customary to measure using something that will measure the real diameters, as the inside jaws of a dial caliper have flats that affect the measurements. Slug your cylinder throats with a soft lead slug and measure them in the customary way. Then slug your barrel and measure it in the customary way.

The cylinder throats should be as large as the groove (not bore) diameter. However, some "bump-up" was expected with black powder guns, as BP has that hammer-effect that can do that with soft lead slugs.

If you change the way you are doing this, it wouldn't surprise me if the numbers changed quite a bit. Adjustable reamers are available.

 

[Jamie C.]

Concerning what Bad Flynch wrote:

When I use the term "Bore Diameter", I'm actually speaking of the largest ( groove ) measurement, since this is what the bullet/ball needs to fit.



J.C.

 

[Misfire99]

Hi All
When I speak of bore I'm referring the inside of the barrel. And yea what I was doing is not all that accurate. I just rechecked the Pietta again and I got .443". I must have had it in a little off center when I first measured it. And I know what I am doing doesn't give very accurate readings because of the rifling. If I wanted to get a good reading I would slug the bore. I might do this in the future. The calipers do give a good reading on the chambers in the cylinder because there is no rifling.

On the ASM pistol the readings I get has the bore, with the calipers just stuck in the muzzle, at least .010" over size of the chambers of the cylinder. Now it would be nice to ream it out to .460" but there are two problems with that. The first is nobody make a ball or mold for a .460" bullet, ball or conical. The second problem is in the wall thickness between the chambers on the cylinder. Right now I read .047". If I reamed it to .460" the wall thickness would be .037". I suspect this would have some issues associated with it. Something along the order of a large boom and a cloud o smoke. I hadn't looked at that until after I made my first post.

At this point I think the only way to fix this gun is to get a different barrel. But this is a brass frame pistol. I had in the past tried to unscrew the barrel with a homemade but well built action wrench. But I put a lot of force on it and I couldn't get it to turn at all. It has a brass frame and I didn't want to give it any more torque then it already had on it. I think the only way I will be able to get the barrel of is to chuck the muzzle in my lathe and cut the barrel shoulder off right at the frame. I might do this this winter when I'm snowed in. Maybe I should get some books on revolver smithing. Any suggestions?