Coehorn Mortar Projectile

[HotGuns]

Im am seriously thinking of attempting to make a mold for my Coehorn replica. I dont want it to be like a round ball, but rather shaped like a shotgun slug, with a hollow base to reduce weight and possibly stabilize it somewhat. The bore is sized to shoot pop cans at .2.625.

As it is, it'll shoot a concrete filled pop can about 200 yards with 250 grains of 2f.

Does anyone here have an experience with manufacturing a hollow based mold ?
Im sure I could eventually figure it out, but I rather use the mistakes of others as a learning experience.:-D

Here's a picture. The base is made of oak and the tube is 4140 and is half scale.
http://i18.photobucket.com/albums/b130/HotGuns/IMG_0523.jpg

[Buckshot]

...............That's a very nice looking morter and is also a nice turning job, whoever made it! Is that your work? So why are you wanting a cast lead projectile? I'm not expert at these things. I want to make one and have a piece of 1045 that's 4.5x14" but the steady for my 11" Logan won't handle that OD. I have to make a larger one.

Why not turn some slugs out of aluminum? See, I told ya I don't know anything about it :-).

...............Buckshot

[KCSO]

A lead projectile will be considerably hevier than the original projectiles. Most were hollow iron and contained a bursting charge. Also the holow base may not be a good idea with that short bore as the base may continue to expand after the projectile leaves the bore. I tried lead in both the mortar and a 2 1/2" rev war galloper and found that it was a waste of good lead. Rockcrete seems to work the best for economy and all around shooting. My mortar loads were saboted with an attached powder charge in a nitrated bag and we got to where we could drop them on a car hood at 250 yards. My next mortar will be from 6" dia brass.

[HotGuns]

Yes Buckshot I made it a couple of years ago. I made a die for the trunnion caps and made the brass elavation knob. The only thing that is store bought are the lag bolts that I used. The paint is black hammerfinish paint. Being a machinist has its advantages...:mrgreen:

I have considered using some scrap stock to make slugs from. Only thing is I might not be able to find them once they are shot.

KCSO,you're probably right about the lead...escpecially as its getting harder to get these days...I might ought to save what Ive got for casting bullets.

I guess the next best thing is to make a mold of some sort that I can cast with concrete.

[Frank46]

Why not just fill up the pop cans with concrete?. I'd be kinda leery of a concrete projectile coming apart as it leaves the barrel. Besides you would not want to spoil all that really nice machining and the bore. Frank

[HotGuns]

The concrete filled pop cans are what I am using. Its just kind of tedious making them up. I figured it'd be easier to just drop some slugs out of a mold and be done with it, but maybe not.

It may be that turning some out of auminum may be the way to go.

[Frank46]

Just a thought, instead of using concrete with the rocks in it Try mortar mix (no pun intended) or sand with some portland cement added. Frank

[HotGuns]

Yeah Frank, thats what Ive been using...its a lot "cleaner:.

[Pepe Ray]

Are you removing the top end of the can before trying to fill it?
I'm picturing you putting cement thru the pop top hole [smilie=1:
Other wise I cant think of a much easier way to fab projectiles.
Pepe Ray

[HotGuns]

No. Actually I pour it through the opening in the can and let it set up for a day or so. Then I send it on its way, but I've never had a can that I could reload, as it messes them up.

[omgb]

I saw a couple of guys a few years ago who were using plastic coke bottles filled with cement. They seemed to work pretty well. the cannon was set up on a bluff over looking the Missouri river out back of Malmstrom AFB in GF MT. I don't know the charge, it was several years ago. But, they were trying to hit an old Chevy more than 1,000 yards across the MO. The shot was across the river and down. The cliffs we were on were a good 300 feet above the river and the car was partially submerged on the opposing side. They dialed in a heap of elevation and actually hit real close to the dang car once out of maybe 8 shots. That shot could skip a ways too. Lots of howeling and whirring as it skipped of the water and slammed into the cliffs on the other side. It was plinking at it with my Cap and ball Remington clone. With a ton of elevation I actually hit the car a few times. Well, two times IIRC:roll:

[DLCTEX]

I wonder if the plastic pop bottles would work filled with sand?

[shooter575]

There are quite a few teams shooting mortars in the N-SSA. 12 and 24lb coehorns mostley,a few 42lb and 8".The small ones everyone uses zinc RB. A 12 lb ball is 5.62 dia @ a short 8 lb in zinc. Out base charge is 325 gr of cannon grade BP.We use 5-25gr kickers as needed. The CW small mortars used fixed elevation.
There are a few pics on my Fotki site
http://public.fotki.com/shooter575/artillery_and_mortar/everything_artillery!/
also in the Marion 2004,Richmond 2005 folders

[fourarmed]

dale, I think a bottle of sand would be like a too-soft cast boolit. The base would start moving before the nose did, and the bottle would slump and split into fragments before it ever got out the muzzle.

[M.A.D]

Im am seriously thinking of attempting to make a mold for my Coehorn replica. I dont want it to be like a round ball, but rather shaped like a shotgun slug, with a hollow base to reduce weight and possibly stabilize it somewhat. The bore is sized to shoot pop cans at .2.625.

As it is, it'll shoot a concrete filled pop can about 200 yards with 250 grains of 2f.

Does anyone here have an experience with manufacturing a hollow based mold ?
Im sure I could eventually figure it out, but I rather use the mistakes of others as a learning experience.:-D

Here's a picture. The base is made of oak and the tube is 4140 and is half scale.
http://i18.photobucket.com/albums/b130/HotGuns/IMG_0523.jpg

I keep coming back and looking at this after all these years and think, dam thats beautiful...

[GhostHawk]

Mad Your not the only one.

Thing of beauty that is.

[elk hunter]

The local cannon cocker uses zink projectiles cast in a mould he made for his 3" parrot rifle. It's been reported that he can hit a 55 gallon drum at 1000 yards but I've not been privileged to witness it.

[samari46]

Years back I watched a video of the cannon shoots sponsored by I think the Paul brothers. I was dumbfounded by the accuracy at 1000yds. Amazing. Frank

[mazo kid]

........I have considered using some scrap stock to make slugs from. Only thing is I might not be able to find them once they are shot.
Several years ago a couple of friends (also machinists) made bowling ball mortars. They had an eyebolt tapped into the balls with a length of brightly colored ribbon tied into them. When I asked if that was to see them in flight, they replied that it was so they could find the balls when they buried themselves in the ground upon returning!