Help Size Bore For A Cannon.

[kvt]

I am wanting to make a cannon that fires 22 pellets, what size of bore would I need for it. Or I want to make one that will fire 1/4 inch sling shot steel balls. What size bore would I need. I know that it cannot be the exact size of the item or it will get stuck, and If it is to big you lose all of your force around the projectile, instead of sealing and pushing it out of the barrel properly. Part of the reason I am asking is I was going to order a Reamer to ream out the bore of the cannon and need to figure this out. Since the cannon will be a smooth bore, I figured that will be the best way to do it, also know that the wading behind the projectile on the cannon should also provide some sealing for the projectile. Any assistance someone can provide would be greatly appreciated.

 

[Terrywerm]

Ken, you are basically creating a short, smooth bore muzzleloader when you make a small cannon. So, you will want to use the same things as a muzzleloader. Many people mistakenly think they can use any old powder and that any idiot can figure out how to pour powder into the barrel and ram a ball down on top of it. Believe me, it is not that simple. Entire books have been written on the subject. I highly recommend that you get some instruction from someone that is very experienced with muzzleloaders. There are dozens of variables when creating a load, and dozens of things that can go wrong. For your own safety, please seek out proper help. I can help you with some basics, enough to get you started, but to teach you everything that I typically teach to others would require you to make a trip to Minnesota for some serious range time. I am nationally certified to teach muzzleloading through 4-H and the NMLRA, so yes, I could teach you, but you will just have to trust me when I say that you would be best off to get some hands on instruction from someone who is genuinely knowledgeable on the subject.

To figure out the bore, obtain some of the steel balls that you plan to use. Let's assume that they are exactly .250" in diameter. You will need to allow for a cotton patch to fit between the ball and the bore because the patch wraps much of the way around the ball. Patches are commonly available in .010" as well as some other thicknesses, but .010" are probably the most common. So, add one patch thickness to the diameter of the ball (.010 + .025 = .035") arriving at a desired bore of .035. You might think that it should be .045, but the patch needs to compress a little bit, which is why we only make the bore .035".

If you prefer to shoot .22 caliber pellets, do this: purchase a .22 caliber rifled sleeve from Brownell's, then machine your cannon bore to accept the sleeve using a good firm press fit, or better yet, make it a shrink fit. If you shoot pellets, you will not need any patches, more about that shortly.

What do you plan to use for powder?? This is an important consideration. If you are going to use black powder, such as Goex or Swiss, you will want to use FFFg (3F). If you are going to use black powder substitutes, such as Pyrodex, you will want to use 'P' type, which is similar to 3F. If you use Triple 7, American Pioneer, Shockey's Gold, or Black MZ, you will want 3F. Next question is how much powder to use. Keep in mind that it is very important that you ALWAYS use a powder measure of some sort, never pour powder from your container directly into the barrel. From experience I can tell you that 7 to 10 grains (by volume, not weight!) will be great plenty when using any of the powders listed above. Ten grains of 3F will give you consistent shots with a .22 caliber pellet at 50 yards. If you use Triple 7, use 10% less as listed in the instructions that come with the powder. One last note on powder: NEVER USE FFFFg ( 4F ) POWDER AS A MAIN CHARGE. And I mean NEVER! Period. Don't do it. Powder that fine creates dangerously high pressures when it burns in a confined space. Also do not be tempted to use modern smokeless powders.

When you load, measure then pour in your powder first, then center a lubed patch over the muzzle, and place a ball over it, then ram the ball and patch down on top of the powder. No need to ram it hard or hammer it down, just press it down firmly on top of the ball. MAKE ABSOLUTELY CERTAIN THAT THERE IS NO AIR SPACE BETWEEN THE POWDER AND THE PATCH AND BALL! If you use pellets, you will not need to worry about the patch, just your powder and then the pellet. The no air space rule applies for pellets, too. Also make absolutely certain that you do not accidentally double charge the bore.

When black powder burns, it leaves behind some residue that builds up inside the barrel just above the point where the ball or pellet rests on the powder. This residue will build up very quickly in a small caliber piece, and can cause the ball or patch to stop short of the powder when you ram it home. This will cause an air gap between the powder and the projectile, which when ignited, has the same effect as an obstructed barrel. In a mild case, and obstructed barrel or an air gap will 'walnut' or bulge the barrel. In a worst case scenario, the barrel could explode. To prevent this from happening, you will want to run a damp cleaning patch down the barrel after every shot. Not wet, just damp. This serves the double purpose of removing the powder residue as well as extinguishing any smoldering embers that might remain in the barrel.

I could go on and on, but what I have provided here is enough to get you started. Have fun, but be safe, and seek out some good help. If you choose to ignore any of the warnings given here, all I can say is that it has been nice knowing you.

 

[Tony Wells]

Terry, methinks you slipped a decimal point there somewhere.

 

[Terrywerm]

Naw, it's just an optical illusion! Thanks Tony, for pointing out my error!

The correct size for a .250" round ball plus a .010" patch would be .260" for the bore. My bad!!

 

[kvt]

I was just unsure of what size, you are right that I originally figuring the patch twice, thus I would have had a lot of blow by. Plus I think I will go get some of the 1/4 inch sling shot ammo before I start just to make sure what size it is, I Don't want it to big, but I guess I could ask my cousin for one of his lead ball makers, (he does a lot of muzzle loading stuff) then I would have consistent ammo. I mostly want it as a show and also to make small amount of noise of things like the 4th. I would love to make me a big bore one that shoots golf balls but that is a bit much for where I live.
And I had not thought about using a sleeve if I used a .22 but That also sounds like a good Idea. And yes I was looking at the Pyrodex, with a 1.8mm fuse, (cousin would prob not like it as he likes to keep things original style). He even does the old civil war reenactments, and some of the muzzle loading demos etc, but he does not really believe or do much with computers so I thought why not through it out here and ask the questions. I really do appreciate the information and will take it to heart.

 

[JPigg55]

To add to Terry's comments, I have a few suggestions.

1. 1. If you go the barrel liner route, consider reaming out the rifling. If you leave the rifling, use only lead. As an example, a 25 cal (0.25") barrel line has lands with distance between less than 0.25". While it may well still push a steel ball through it, barrel/breech pressures will be much higher increasing the likelyhood of failure.
2. 2. I'd suggest (at least initially) using lead projectiles. Lead is a lot softer and more maliable than steal balls. Less chance of binding in the barrel.
3. 3. Newspaper works well as a patch at least for smooth bore, that's what I use on my cannon. Just make sure the burning paper won't start a wildfire.
4. 4. Be careful and don't underestimate the power and range of your cannon. I have a 1/2 scale Napolean smooth bore cannon from Dixie Gun Works. It's a 3' barrel with 2 1/4" bore. I mold 2 lb lead sinkers to use as cannon balls. With a 1000 grain charge, it will toss those 2 lb projectiles more than 2000 feet through the air.
5. 5. 3F may work for the smaller bore, but mine said to use only F or FF powder. The more F's, the finer the mesh/grain, this results in more surface area and faster burn rates resulting in higher pressures.
6. 6. Powder charge. The recommeded maximum charge on mine was 500 grains. That said, they had a disclaimer that during testing, they loaded 2.5 lbs of 1F powder before the barrel failed. Usually what happens with an overcharge of black powder is the excess is just pushed out and burns outside the barrel up to the point where the powder itself acts like a blockage. Just know to much is a waste of powder up to the point it becomes dangerous.

 

[Terrywerm]

Jeremy posted some good thoughts, however I would not ream out the rifling in a sleeve. My suggestion of using a liner would be only for using .22 caliber lead pellets as the ammo. The .250 steel balls would never even fit in that liner, and would require a smooth bore. You don't need a liner to create a smooth bore. For a smooth bore, you wouldn't even need to use a reamer, just drill it to size. The couple of thousandths that it might be off in diameter would be easily taken up by the patch.

Due to the short length of the barrel, accuracy at any range will be almost non-existent, especially with a smooth bore. The rifled .22 bore would give you some accuracy with the pellets, but it would still not be great.

One other thing to think about is using lead balls instead of steel, as already mentioned. Ball size needs to be consistent. The only problem with using lead balls is that the smallest lead ball available is for .32 caliber. Hornady has them available in either .310" or .315" diameter. If I was going to a .32 caliber, I would go with a .320" bore, then use the .310 balls with .010" patches.

As for the powder, 3F would be ideal for a .22 or .32 caliber, or even for a .45 caliber. The general rule of thumb is to use 3F for anything under .50 caliber. Use 2F for .50 caliber up to about .80 or .90 caliber, and use 1F for anything larger than that. Jeremy, I am surprised that Dixie Gun Works even recommended using 2F in that large a bore. You are correct though in your statement about overcharging with black powder, the excess is generally wasted as it burns as it is going downrange, where it does no good.

One last note, you can shoot blanks easily by simply ramming a few patches down the barrel on top of the powder. Four or five patches and no ball usually works very nicely.

 

[GA Gyro]

Terry...

Do you by any chance know Stan Foster in Ill... he was a national Musket champion years ago.

 

[Ozwelder]

Thanks for that Terry,
I was at the range yesterday and saw 4ffff powder used for the first time in 25 years of muzzle loading. They were using 4fff powders to re prime a dry balled shot in a newbies percussion cap rifle. I understand the 4fff may have been flash pan powder I am pleased to find this warning here. It just adds to that store of little things of what should be known about a potentially dangerous activity. I was surprised that such a tiny bit of powder could drive the ball out of the barrel.

 

[kvt]

Thanks for all the information. And better than some of the sites that sell cannons, and materials. I watch a vid on one that sells the .177 cannons, They said just put what looks close to the size of a pea on a piece of folded paper and pour it down the barrel then ram it down and mark the ram with your finger, the pull it and put it over the top of the barrel. If the powder was not up to the trunions you were ok. That is a little scary to me. And that was the cannon maker. I mostly want it for noise.