Bowling Ball Mortars

[drhall762]

I am going to put this here since I see it as a ML. I have wanted to build one for a while. I have a nice high pressure cylinder to use and a very reliable chamber design. I have found that the ATF classified the Stokes mortar, if fired with black powder and BB as a reproduction antique so now I am vey happy. The biggest hurdle for me was projectiles, or should I say the lack of them. I would have thought it easier than it was to find old, unwanted BBs. Finally I discovered some. About 68 to be exact, 8 - 16#. Made my first pick up of 16 and even got a nearly new AMF BB rack with the deal. As soon as I pick up the rest the build will begin.

Try to keep you posted.

[johnson1942]

bowling balls are tough also. i set one ontop of my 100 yard target barrel and the 270 and 45/70 didnt to anything but put hard to find holes in them. it took a .50 cal paperpatched 720 grain bullet with 100 grains of 2f behind it to finally knock it apart. you might be able to shoot them over more than once. make a golf ball cannon and go to a big golf course and find the lost golf balls to shoot. a guy up along the big lake in n.dak. had a real nice one and shot it over the lake and it was as the young people say, awsome.

[drhall762]

Golf balls are easy. I have a friend that gives them to me a 5 gallon bucket at a time. They are fun but there is just something about a 16# projo hurling through the air. Just gotta' build one.

[Hardcast416taylor]

bowling balls are tough also. i set one ontop of my 100 yard target barrel and the 270 and 45/70 didnt to anything but put hard to find holes in them. it took a .50 cal paperpatched 720 grain bullet with 100 grains of 2f behind it to finally knock it apart. you might be able to shoot them over more than once. make a golf ball cannon and go to a big golf course and find the lost golf balls to shoot. a guy up along the big lake in n.dak. had a real nice one and shot it over the lake and it was as the young people say, awsome.

New a guy that got paid a visit by his local police along with state police and Coast Guard officers over a golf ball. Seems my friends kid made a golf ball mortar in shop class. He then was shooting the balls at freighters in a great lakes river channel. A ball was discovered on the deck of a freighter that was in the mid river traffic channel, probably close to 700 yds. from shore!. The ball had my friends name and address on the ball, Xmas gift. As any golfer loses balls when playing the officers couldn`t pin any rap on my friend. The mortar when the boy fessed up to it was made to sledge hammer the barrel shut!Robert

[bikerbeans]

I am going to put this here since I see it as a ML. I have wanted to build one for a while. I have a nice high pressure cylinder to use and a very reliable chamber design. I have found that the ATF classified the Stokes mortar, if fired with black powder and BB as a reproduction antique so now I am vey happy. The biggest hurdle for me was projectiles, or should I say the lack of them. I would have thought it easier than it was to find old, unwanted BBs. Finally I discovered some. About 68 to be exact, 8 - 16#. Made my first pick up of 16 and even got a nearly new AMF BB rack with the deal. As soon as I pick up the rest the build will begin.

Try to keep you posted.

Your my new hero! I would love to have a BB Mortar but the wife said no. I loved the video of the BB Mortar in Alaska and the guys launching BBs +700 yds. Apparently 3 oz of black powder has a good deal of stored energy.:-D

BB


http://www.docsmachine.com/nonPB/mortar.html

[John Taylor]

Lots of fun putting a 16 pound ball out of sight. The finger holes make funny whistling sounds going up and coming down. Just got enough tube in for making four more but it has a little chrome ( high pressure steam pipe) in it and I can't cut it with a torch, need to find someone with a big saw.

[Sergeant Earthworm]

"Honey, what's this bowling ball doing in the living room? And how did we get a hole in the ceiling?"

[drhall762]

Plugging the holes adds a bit to the cost but it provides slightly better ballistics in theory.

[historicfirearms]

What are you guys using for a barrel? I've got a good condition oxygen cylinder, but am not sure it would hold up to the pressure of launching a bowling ball. I've thought about making some other projectiles, possibly out of hardwood on the wood lathe.

[drhall762]

You are on the right track. The cylinder is just a barrel. The key is the chamber in the bottom that holds the powder. The whole mortar kind of works like a 40mm grenade cartridge with the high/low pressure system. The chamber holds the powder at the base of the tube and the ball fits down the barrel and sits on the chamber. Let me find the link to a good drawing of this. It is the same one I used and I will post it.

[drhall762]

Okay, here are a few that I used to get my ideas. I am going with a Stokes design now that it is ATF okayed rather than the older Coehorn. The first link is the Forum section and the rest are specific topics.

http://www.go2gbo.com/forums/index.php/board,88.0.html?PHPSESSID=vvi2lrmundgae38nfr90unni d0

http://www.go2gbo.com/forums/index.php?topic=251175.0

http://www.go2gbo.com/forums/index.php/topic,206743.0.html

http://www.go2gbo.com/forums/index.php/topic,259494.0.html

http://www.go2gbo.com/forums/index.php?topic=205524.0

The only thing on my build I take credit for is the T&E Mech which is a variation on the standard Stokes T&E, and my firing system for which I will jump for joy if it works as designed. I am sure even it is not wholly original. Very few original ideas left when it comes to 100+ year old weapons.

Hope these links help get the juices flowing.

[historicfirearms]

From your third link, one of the posts lit a lightbulb in my head

"Actually there is some very clear safety guidelines for chambers and breech plugs found N-SSA rules. You must keep in the mind the breech plug/powder chamber is a small cannon. The barrel on the bowling ball mortar or any of these type mortars is simply an expansion chamber and a holding fixture for the ball. The ball in this case doesn't go down the bore but sits on the muzzle of the cannon. "


Makes sense to me. Now I've got another project to do...

[John Taylor]

From your third link, one of the posts lit a lightbulb in my head

"Actually there is some very clear safety guidelines for chambers and breech plugs found N-SSA rules. You must keep in the mind the breech plug/powder chamber is a small cannon. The barrel on the bowling ball mortar or any of these type mortars is simply an expansion chamber and a holding fixture for the ball. The ball in this case doesn't go down the bore but sits on the muzzle of the cannon. "


Makes sense to me. Now I've got another project to do...

The powder chamber is just a place to hold the powder. The tube will contain ( hopefully) all the pressure that is developed. Pressures do not get near as high as in a rifle because of the area of the bore. The area is about 58 cubic inches for each inch of bore. In a .50 cal. rifle it is only .196. In comparison the bowling ball needs very little pressure to make it move because it has 296 times the area.