New to the Forum

[greenlaser]

Hi everyone.  I've been reading through old posts for several days now, and I thought I should say hello since I'm starting to get to know you.  What a knowledgable group.

I will be building my first cannon soon, and I am sure you have guessed that I am full of questions.  I will be reading all the posts again, so I will not be flooding you right now.

A friend of mine has some drill stem that has a 2.5 inch bore and the walls are 0.5" thick (I have not had a chance to actually measure it yet).  From table 10.1 from "Artillery Matches" the maximum charge is 5.00 ounces with a 2 lb projectile.  He has been shooting 4 ounce charges and has had no problems (his cannon is about 8' long).  I do not know what *kind* of steel this is.  Has anyone used drill stem, or have any information about it?

Given that charge and projectile weight, what would be an optimum barrel length?  Since there is little friction between projectile and bore I would guess the barrel could be long, but I would also guess that at some point the extra length would not pay back much in extra velocity, and just make building, cleaning and moving more difficult.  Any thoughts on barrel length will be appreciated.

I will be shooting concrete *soda* type projectiles.  I just need to find a can that allows the right windage.

Thanks,

Jim

Calamity, love that cannon!

[Cat Whisperer]

GreenLaser -

Welcome to the forum!  I encourage you to pop a few questions now and then - it sparks us to some good discussions.

Any cannon with an 8' long tube has got to develop some SERIOUS velocity.  It should be able to maximize the really slow powders too.

Most of my work is with mortars - most with bores that are about a 1/4" longer than the can they fire.  ONE with a bore length of about two 24oz pepsi bottles - and it gets seriously longer range.

Consider where you have to shoot first.  If you only have a 100 yard range you'll be frustrated with an 'iron that reaches out 600 to 1200 yards.

MY next consideration is ammunition availability - and the mortars I've built are in: golf-ball, soup-can, beer-can, 16-20-24oz pop bottle and 4" pvc pipe calibers for obvious reasons.  

You might want to compete in the N-SSA competitons (next month the Nationals at Winchester, VA) where the calibers and design should be histerically correct - another very real consideration.


Drill stem - hadn't heard the term, but if you find someone in the trade of drilling wells (I assume) that you'd be able to learn a lot.  Iwould think it would be a reasonably strong steel, and may or may not have seen some abuse.

Good luck & keep it safe!

[Double D]

Jim,

I am reasonably sure drill stem is seamless.  If it's welded, pass on it.

Where are you  in Big Sky...I was forced to move from north of Cut Bank due to greed... promotion and money.

[greenlaser]

I was seeing cannon here in 4145 steel:

http://www.wncovalve.com/rotary_subs.htm

I even checked on price.  a 2.75 inch bore with an 8 inch OD and 4 feet long would be $850.  It was in stock.  I did not ask about shipping.

I'm only 15 miles from the Two Dot Bar.  Just about the center of the state.

question: How far up the breech do you need one calliber thickness?

Here is an example of a cannon that really does not follow the one calliber spec and it is commercial.

http://www.diamondbackcannons.com/index.html

It has a 1.75 inch bore and 3.375 inch breech.