Blackpowder, bowling balls and sewer pipe!

Swinging comically oversized mallets since 1998

One Fine September Morning...

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10-21-03: Updated for all of those visiting from Fark, Slashdot and [H]ardocp among others. I had no idea this page would be so popular when I posted it last year, but as long as you're here, feel free to have a look around. I've added a sort of FAQ at the bottom, in reply to the many E-mails I've received to date.

Ah, serendipity. Being in the right place at the right time.
As it happened, this fine and sunny September Sunday morning found me and a few others at the local gun range, sighting in- or trying to- some rifles. Some were cooperating, some weren't. A normal outing to the range, really...

Until this fellow pulls up and starts unloading a big 'ol hunk o' pipe.

Pipe? Bowling balls?

I thought he was going to bury it as a new target stand or something.... 'til I saw the Bowling Balls. It could only be what some call a "punt" mortar! I'd seen similar handmade ones on the 'net and in magazines... naturally, we all completely forgot about our own rifles for the moment.

How far'zat thing go, anyway?

The Gun Range is a nice place- raised, covered shooting line, plenty of tables, well-kept grounds. The first line of targets is at 100 yards, with small berms and pipe target stands at 200, 300 and 400 yards as well, plus a trail/road to drive up to 'em if you need to. And at 500 yards, right at the base of the stand of trees off in the distance, is a full-size steel cutout of a moose, painted day-glo orange. Above, the guy with the mortar is pouring in some three ounces of Fg (coarse) Pyrodex black powder...

This sucker is huge!

This thing is huge! Probably weighing some 150 pounds, half-inch-nominal wall pipe with a massive two-inch-thick breechblock welded on one end. The touchhole or fuse passage leads to a small "chamber" in the center that holds the powder in a single spot, rather than letting it cover the whole 8.5" bore.

Crude, but it works.

Crude, yes, but it works. The owner is reluctant to do any additional welding on the pipe, for fear of making a weak or brittle spot, so he just stacks up whatever's handy to hold it, oh, 'bout there or so. This thing's so cool I want to make the guy some adjustable legs like the old 4.2" Chemical Mortar had....

Fire in the hole!

Three ounces of Pyrodex, an old garage-sale-special bowling ball, an old chair and some sewer pipe... Fire in the hole!

I'll be over here where it's safe...

He's not running, but he ain't dawdling either! Let's see, the fuse burns at about one minute per foot, there's about six inches there... dum da dum... carry the three...


HOLY FREAKING BATTLESHIP MISSOURI! By the time the shutter snapped, the ball was, in relation to this picture on your screen, about six monitors up and climbing. It was whistling. I lost track of it since I was trying to get the picture, but the guys say it cleared the treeline by probably another hundred yards.

Let's do that again!

Let's do that AGAIN! Rod out the fuse hole, make sure there aren't any errant embers, pull the mortar up out of the divot it created, weigh out another charge of powder, another bowling ball... This time I was watching downrange with the camera pointing at the cannon... Holy Creeping God, ladies and gentlemen! That ball was screaming out of there! I'd wager it landed over 600 yards downrange.

I should have brought out my Radar Chrony. I'd guess that ball wasn't moving over 700 fps, possibly as low as 400 fps, but jeez, think of the mass! That ball's what, eight to ten pounds?!? What's the Hatcher's Index of a projectile weighing fifty-thousand grains moving at 400 fps? "Body armor" against this thing is eight feet of dirt over a concrete bunker!


Think Grandpas' old thirty-thirty is a kicker? How about a hundred-plus-pound gun that pushes itself into the dirt six to eight inches each time it goes off? This is not a shoulder arm.

After all four balls were expended, we helped load it back in the guy's car. I noted that there were some divots from earlier shoots... he said he gathers up old balls whenever he can find 'em, then when he has a few, on a nice day he'll come out and blow 'em downrange. Says it always draws a crowd. I said "so there's already a few balls out there in the swamp, eh?"
"Oh, more than a few, yeah."

He says he also has a short cannon that takes small tomato-sauce cans and another mortar that takes soda cans. The soda cans, it seems, don't hold together well- the force of firing blows the can off the concrete fill, which then blows up in the air.

Besides, he says, NOTHING beats seeing that bowling ball howl downrange as far as the eye can see.

I agree. :) The pictures don't do this justice; this is something every Tinker or gadget freak should see in person at least once in their life.

Doc's Mortar Page FAQ:

Q: Come on, this can't be legal.
A: Actually, it is. The laws vary by state, of course, but generally speaking, if it's a smoothbore, loads from the muzzle, and fires blackpowder and not in a self-contained metallic cartridge, it's legally classified as an "antique" and is not subject to the usual regulations concerning firearms. (Check your local laws before trying this!)

Q: Is that yours?
A: No. I just happened to be at the range and have my camera with me when the owner showed up.

Q: That's cool, but you should have gotten some video!
A: If my camera were capable of it, I would have. I was lucky to even have had it with me. However, I have a sort of "open invitation" with the owner: if I bring the ammo, he'll bring the pipe and powder. I have four old balls already, when I have six or seven, we'll make a day of it, with digital video, faster cameras, and maybe a chronograph.

Q: Will you build me one? Or, can you tell me how to build one myself?
A: No, and no. First off, I didn't build it, so I don't know the specs. Second, unless you lived in Alaska, shipping a 150-pound section of pipe will get pretty expensive. I do know the pipe they used is extra-heavy-duty, and the fellow that did the breechplate welding is a 20+ year professional pipe welder experienced in heavy industrial refinery process plumbing. If your welds can't pass an X-ray inspection, don't try it yourself.

Q: Okay, do you know anyone who can make me one?
A: Sure. Give Dave a call at Alconda Machine. He helped build the original, and has built several smaller versions. In addition, he also has some fantastic cut brass ornaments and built an amazing aluminum-bodied electric guitar.
Have a look, and be sure to tell him Doc sent you.

Q: So why is it just stacked up on an old chair?
A: At the time, the owner was reluctant to do any additional welding to the pipe, for fear of making a weak or brittle spot. At this shoot, I suggested he make some legs, but ones that clamp on, rather than being welded on. I'm told that he has been working on just that, using a set of old 4.2" Chemical mortar legs he found on Ebay.

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09-15-02 All text, photos and graphics Copyright 2002, 2003, Doc's Machine & Airsmith Services. All rights reserved. Unauthorized duplication prohibited. For entertainment purposes only. If you blow your eyebrows off with a blackpowder sewer-pipe cannon, it's your own damned fault. Blackpowder may seem like fun here, but it's a dangerous explosive. Know what the hell you're doing before you go putting bowling balls into orbit.