Caliber question

[mjpchief]

About 2-3 weeks ago I posted about a rifle that was given to me by a friend. I measured the bore at the muzzle and figured it to be a .40 cal. I have brought the old rifle back to life and was going to order some balls for it. Just this morning I measured again only this time I went about 2" into the bore and measured there. The measurement I got at this location came to .375. Would this be a .36 cal or a .38 cal? I noticed that some of the .36 balls measured .375. Not going to shoot this rifle much but I want a bag of balls to be with it. This measurement was on the lands not the grooves.

 

[Rifleman1776]

It sounds like a slightly coned bore. The size further down is what is important. The best (only) way to determine what works in that rifle is to load a ball you believe to be close to what you need. And, of course, shoot it out. A .375" ball is most frequently used in cap and ball revolvers because they are shaved down to fit the cylinder then force squeezed further into the barrel so they will engage the rifling. You can take advantage of this same concept by getting some pure lead soft .375" balls and loading them with a popular patching, like ticking and a proper lubricant on the patch. If that loads only with difficulty, be sure to seat fully before shooting out. Then go look for a smaller ball, like .350". Best performance can only be determined with trial of several ball sizes, patch materials and thicknesses and lubricants. But what I suggested will get you started safely.

 

[Grimord]

Another way to verify the bore size is to slug it. Place a short length (4-6") of brass or steel rod that will slide down the barrel. Then take a pure lead ball ( in your case maybe a .390 ball) and start it down the bore using a wood dowel and mallet to pound the ball into the bore for about 2-3". Now shake the gun so that the brass or steel rod bangs against the slug until it comes out, then measure the slug with micrometer or calibers to get the land to land measurement. You now know the bore size, and get the appropriate size ball and patch combination.

 

[bang]

If it's 40 at top, 375 2 inches down, I would get a 3/8 dowel rod. If it won't go you can probably take it to the bank it's a 36 cal and the barrel is cone shape all they way. In which case a 350 ball and .010 patch maybe .015 patch. If it shoots good great. If not new barrel.

 

[Grenadier1758]

Have you had a black powder, muzzle loading gunsmith take a look at your rifle?

As Rifleman1776 stated, you have a coned muzzle for ease in loading a patched ball. Determining the caliber of a rifle is best done by measuring as you have done. The ball size needed is determined by the diameter across the lands. I am assuming that you have an even number of lands and grooves. Let us know as this can make a slight difference in recommended ball size. Grimord's method is great for determining a bore diameter and counting the lands although I prefer a slightly longer just under bore diameter 11/32" or 5/16" brass so the removal is gentler on the barrel . You want a ball to shoot that is about 0.010" under the land to land diameter. Let's be gentle to your rifle so I would select a 0.360" diameter pure lead ball. I would use a thick patch of 0.022" denim or canvas as a patch material. The thicker patch material will fit into the grooves better and compress to the land to land diameter. To start out, any good oil such as olive oil, canola oil will do a good job for the trail shots. Powder of course should be 3fg black powder.

In the hand gun section there more than a couple of threads on calibers, especially 36. A 36 caliber revolver will require a 0.375" pure lead ball to fit the cylinder as no patching is required and lead is shaved off the circumference of the ball to seal the cylinder and hold the ball in place during firing of the other chambers in the cylinder. The land to land measurement in a revolver is the 0.360" and the excess lead will fill the grooves. A rifle or single shot 36 caliber pistol that requires a patched ball will also have a land to land diameter of o.360". However a patch is needed to seal the grooves and carry lubricant to the barrel while holding the ball and engaging the twist of the barrel to stabilize the ball. A ball 0.010" under the land to land diameter is a good choice for ease of loading and integrating with the patch for good performance.

Your rifle would be a 37 as it came from the gunsmith/builder. We can happily call it a 38. Fortunately we can find balls to fit your barrel. And as seldom as you are planning to shoot it, use a 0.360" ball.

 

[mjpchief]

Thanks for the quick responses. I tried a 3/8
dowel rod and it will only go in about 1/2-3/4" and won't go any further. Barrel is definitely coned. Should be easy to start a ball. If the barrel is shot out I will just put it up. It's an original 1863 rifle.

 

[Grenadier1758]

Delete this

 

[mjpchief]

Have you had a black powder, muzzle loading gunsmith take a look at your rifle?

As Rifleman1776 stated, you have a coned muzzle for ease in loading a patched ball. Determining the caliber of a rifle is best done by measuring as you have done. The ball size needed is determined by the diameter across the lands. I am assuming that you have an even number of lands and grooves. Let us know as this can make a slight difference in recommended ball size. Grimord's method is great for determining a bore diameter and counting the lands although I prefer a slightly longer just under bore diameter 11/32" or 5/16" brass so the removal is gentler on the barrel . You want a ball to shoot that is about 0.010" under the land to land diameter. Let's be gentle to your rifle so I would select a 0.360" diameter pure lead ball. I would use a thick patch of 0.022" denim or canvas as a patch material. The thicker patch material will fit into the grooves better and compress to the land to land diameter. To start out, any good oil such as olive oil, canola oil will do a good job for the trail shots. Powder of course should be 3fg black powder.

In the hand gun section there more than a couple of threads on calibers, especially 36. A 36 caliber revolver will require a 0.375" pure lead ball to fit the cylinder as no patching is required and lead is shaved off the circumference of the ball to seal the cylinder and hold the ball in place during firing of the other chambers in the cylinder. The land to land measurement in a revolver is the 0.360" and the excess lead will fill the grooves. A rifle or single shot 36 caliber pistol that requires a patched ball will also have a land to land diameter of o.360". However a patch is needed to seal the grooves and carry lubricant to the barrel while holding the ball and engaging the twist of the barrel to stabilize the ball. A ball 0.010" under the land to land diameter is a good choice for ease of loading and integrating with the patch for good performance.

Your rifle would be a 37 as it came from the gunsmith/builder. We can happily call it a 38. Fortunately we can find balls to fit your barrel. And as seldom as you are planning to shoot it, use a 0.360" ball.

A friend has a mold that throws a .355 ball. I think I will use this and make a few balls. Just want the old rifle to put a couple down range so the guy that give me the rifle can see it shoot. His grandpa give him the rifle in 1947 and he never shot it.

 

[mjpchief]

Couple of pictures of the old girl.

 

[Zonie]

If the 3/8 inch rod won't go down the bore to the breech it is very likely the barrel is a 36 caliber. If so, you will want to use a .350 diameter ball along with a suitable cotton patch.

One of the nice things about shooting patched balls is you can vary the patch thickness to accommodate the bore size. If it is too loose, use a thicker patch. If it is too tight, use a thinner patch.

 

[bang]

Still a nice piece of history.

 

[Grenadier1758]

A friend has a mold that throws a .355 ball. I think I will use this and make a few balls. Just want the old rifle to put a couple down range so the guy that give me the rifle can see it shoot. His grandpa give him the rifle in 1947 and he never shot it.

Using the 0.355" ball sounds like a good plan. After all, if its too loose, use a thicker patch. If its too tight get a thinner patch. Treat your old gun gently.

 

[mjpchief]

Using the 0.355" ball sounds like a good plan. After all, if its too loose, use a thicker patch. If its too tight get a thinner patch. Treat your old gun gently.

It will be shot with a light load. Just want to see it make smoke and will put it to bed.

 

[Rod Man]

Are there .355 moulds out there? I ask cuz I haven’t had a chance to look around. I just discovered today that the bill large barrel I bought from @BigSkyRambler is too loose with a .350 ball and .015 patch. You push the ball down with your thumb. Going to try an .018 next. If that doesn’t work will need to order some .02 or .355 balls. It’s a 45” almost chunk gun.

Thoughts???

RM