Chamber To Barrel Alignment


June 3, 2006, 03:48 PM
Can somebody please touch on this subject (Cylinder chamber to barrel alignment) for BP Revolvers. And what to look for at gunshows. I found this
subject for centerfire weapons but not for BP. I would also like more info. on cylinder play. Seems like more and more people are going to gunshows and
getting good deals and some not so good. Maybe just maybe I'll walk away with a good deal. thank You

If you enjoyed reading about "Chamber To Barrel Alignment" here in archive, you'll LOVE our community. Come join today for the full version!
June 3, 2006, 04:58 PM
Empty and at the full cock, hold a flashlite to the side of the cylinder at chamber end and forcing cone. Look down barrel to see if the Cone is centered with the barrel. i.e. Chamber completely visible thru barrel. 1/4 moon means over or under clocked. Will shave balls when fired. 1/2 moon don't you dare shoot it.
Hope this helped.

June 3, 2006, 05:39 PM
smokin gun Iam trying this on my new revolver and the nipple is center. Iam
having to shine the light at rear(fully cock) of the cylinder since no light shows from the front of the cylinder at the chamber . I don't understand about this moon. Is this the rim of the cylinder corresponding to the opening of the cone (nipple) giving it a 1/4 or more moon effect when not center. Iam having to use a table lamp to get enought light to see. Maybe I need glasses. thank You

4v50 Gary
June 3, 2006, 07:04 PM
Gunsmiths use what is called a range rod. It's a straight metal rod with a removable tip. Said tip is dimensioned for the particular caliber. Here's how we were taught to use it:

Cock the empty weapon and drop the hammer (I lower it by thumb). Do not release the pressure on the trigger. You don't want the hammer to rebound back. With the hammer forward (or resting on the nipple) and the cylinder stop up and engaged in the cylinder notch of the cylinder, insert the range rod. It should not hit the face of the cylinder as it passes from the forcing cone of the barrel into the cylinder. Repeat for all the cylinders. If one cylinder is off, you're going to have side spitting because of the shavings.

June 3, 2006, 11:40 PM
Yes Edggy you have it right..if the chamber is off from the barrel, then you get the 1/4 moon effect visually and physically. Nipple holre dead center of your barrel should be right on dead center. A longer or shorter hand is one way to correct the off centering along with bolt lock up adjustmens.

June 5, 2006, 02:12 PM
There is not much dsifference between a cap & ball and a cartridge revolver as far as chamber to barrel alignment goes. The point of holding the trigger back with the hammer down applies to most double action revolvers or single action revolvers on double action frames but not true single actions. I don't off hand know of any single action revolvers on single action frames that will have chamber alignment checks affected by holding the trigger back.

I look down the barrel with a very slim pencil light and look for a chamber mouth edge. I rock the cylinder back a forth a bit while looking. Ideally, the chamber mouth edge should never be visible. If there is a problem its not going to be any esay one to correct. It's usually due to manufacturing tolerances rather than wear.

End play is another story. Here there are very significant differences netween a cap & ball and a cartridge revolver. Some cap & ball revolver designs, Colt style for one, really don't bother trying to control end play. Another difference is that on firing, a cartridge revolver's cylinder is blown forward where a cap and ball cylinder is blown backward. What's important and what isn't in the end play is different.

A S&W revolver's timing is sensitive to the amount of endplay, they don't tolerate a lot. What's worse is that any endplay tends to increase the rate at which it will develope more endplay. The S&W is a bit delicate in this respect as the tail of the yoke provides a rather small bearing area to control end play in the forward direction.

A the timing of a typical singler action cap & ball revolver on the other hand will not be nearly as sensitive to endplay. The rear of the cylinder will have a large area bearing on the recoil shield to limit rearward travel

June 5, 2006, 07:23 PM
Asked tha boss, he said puts set of machined&hardend plugs in each chamber, has hole in tha center, and rod has a male section that will if alingnment is EXACT slip into tha chamber plug hole.

Does this on rebuilds as he's NEVER found ANY factory revolver that'll be close enough fer this precision check.

Says its a huge pain but he's align honing tha chambers anyway. Says he does it cause with wear/use it only goes downhill from there!

He also laps&hones for chamber and barrel match, sos ifin ya got chambers at .454, tha barrel is gonna be .453 with a nice barrel throat.

When he's lappin tha barrel, ifin its doable, he gives 'em a little CHOKE sos its tighter on tha muzzleside.

THANKS to tha poster, i gots ta learn somethin today!

If you enjoyed reading about "Chamber To Barrel Alignment" here in archive, you'll LOVE our community. Come join today for the full version!