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muzzle loading .50 cal

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Should I build this

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Unread postAuthor: Ragnarok » Fri Dec 05, 2008 10:01 pm

Gippeto wrote:Please keep in mind, 3/4" copper is also NOT 3/4".

I'm nerdy enough that I know the internal calibre of 22mm copper (a UK standard) to 20.29mm - I usually reckon the largest projectile that can be fired without it being fairly tight is 20mm though.
The thing is, it's nominally 20.2mm, but whenever I've measured it with callipers, I've found the bore is slightly larger than that - it also varies slightly, it's less consistent than the outer diameter, which is very tightly controlled.

I eventually found the average by weighing a 2 metre section of pipe and reverse engineering that figure, knowing that the OD was very consistent, and very close to 22mm.
It came out to 1010 grams, divided for 5.05 grams per cm, worked out that a solid disc of copper 22mm in diameter 1cm thick should weigh 33.91 grams, the difference being 28.86g - then worked back from there to work out how much copper would need to be removed from the centre of the 22mm copper disc to make it weigh 5.05 grams, the answer being 2.029 cm - essentially 0.799", but I tend to call it "Eighty cal", 'cos it sounds cooler - or if I'm working in metric, I round to 20.3mm.

Basically, a hair tighter than 3/4" SCH 40 PVC is (nominally) in the US of A. Interestingly, that means those 8ga slugs you linked to would just about fit (if I had a whelk's chance in a supernova of getting them) - might be worth the attention of spudders with 3/4" SCH 40 barrels.

But that's a useful technique for finding the average bore of any tightly OD controlled metal pipe. It's not so great on PVC though, as PVC's density is more variable than that of metals.
It's not very important to know it that accurately, but kinda cool.
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Unread postAuthor: jitup » Fri Dec 05, 2008 10:45 pm

@ Gippeto
thank you for the great links. I like that copper gun. I want to do that to a 2x4 from 50 yards, what you did to the 3/4 at 5. Is it possible? How high of a pressure above 400 psi can I push a copper gun with Co2 in freezing conditions?
After seeing your work I would like to possibly make my own slugs. I do not have a milling machine avalible, would I still be able to make a mold?
Also I can not figure out how to order off that site you listed! I was unable to read the copper doc. (I have SLOW SLOWER SLOWEST dial up)
Where did you buy the nylon stock for your piston valve?
would the below rounds fit into copper 3/4 ? 12ga rounds

@ Ragnarok
I admire your mathamatical brilliance and hope one day I will be as bright. ( I am still pretty young, 17 on a full ride to a communtiy college paid by my home school. I will have an associates degree 2 weeks before my deploma! I am a music major but after discovering the joy of creating things that destroy things I might swithch to mech. eng and sign up w/ the army to be a weapons system engineer)
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Unread postAuthor: Ragnarok » Fri Dec 05, 2008 10:59 pm

jitup wrote:@ Ragnarok: I admire your mathamatical brilliance and hope one day I will be as bright.

It's hardly brilliance, it's just thinking outside the box for ways to find an answer.

I'm not exactly brilliant - I have my moments, but I mean, I was the guy that invented the weaponised spatula, and that was...

... well, just plain retarded to be honest.
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Unread postAuthor: jitup » Fri Dec 05, 2008 11:12 pm

I meant all your knowledge of so many useful formulas, not nessicarly from this post but other that are way over my head at the moment, like the perfect projectile post. Jimmy101 has some major math skills as well.
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Unread postAuthor: jackssmirkingrevenge » Fri Dec 05, 2008 11:46 pm

Ragnarok wrote:I'm not exactly brilliant - I have my moments, but I mean, I was the guy that invented the weaponised spatula, and that was...


How so, care to elaborate? We've been using spatulas as throwing knives in the lab for years now, sharpened the edges and everything, spetsnaz style :)

Finally a soldier is taught to throw the spade as accurately as he would use a sword or a battle-axe. It is a wonderful weapon for throwing, a single, well-balanced object, whose 32-centimetre handle acts as a lever for throwing. As it spins in flight it gives the spade accuracy and thrust. It becomes a terrifying weapon. If it lands in a tree it is not so easy to pull out again. Far more serious is it if it hits someone's skull, although spetsnaz members usually do not aim at the enemy's face but at his back. He will rarely see the blade coming, before it lands in the back of his neck or between his shoulder blades, smashing the bones.
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Unread postAuthor: Gippeto » Sat Dec 06, 2008 3:19 am

You're welcome. Possible, yes. Easy, maybe.

I have not pushed a copper gun past 450psi, and do not plan to. There is a better, and safer material for that. (steel)

Co2 makes a lousy low temperature propellant gas. If, that is, you're running it unregulated (the pressure drops with the temperature).

If the bottle of co2, the regulator, and the gun, are at the same temperature (below freezing), and you are regulating pressure to the gun at a lower pressure than that existing in the bottle, I see no reason why it wouldn't work fine.

Except that air is free, and will give markedly better performance. :)

As for making a slug mold, do you have a drill press? If you do, then a mold, and jigs to make drilling out the base of the projectile accurately (and reproduceably) can be made.

I buy my materials from the local machine shop.

Some details from the copper pipe handbook; (this is a rather large pdf file)

3/4" Type K has an id of .745"
3/4" Type L has an id of .785"
3/4" Type M has an id of .811"

The slugs you posted have an od of .735" and the wad has an od of .740"

A bit loose for my liking, but close enough if you can find type K copper. (I can only get types M and L locally)

Use a heavy card stock disk as a gas check, and you're in business.


Try the home page. All you have to do is shorten the address. :)

http://www.ballisticproducts.com/
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Unread postAuthor: jitup » Sat Dec 06, 2008 3:29 pm

Gippeto
Thank you for all the info. I do not uinderstand the cardstock comment, please eloborate. can you please list the supplyer you got the nylon for (are you state side?) I have a drill press (I own one) and a machine shop nerby (were I can purchase materials) , if it is not to much trouble can you please give me a link discribing the prosess of making lead slugs. do you know of any premade slugs with a .745 id? (would that be to tight? what would be the ideal slug ID for type k)

EDIT what would be better and cheaper to by the round 25 in a pack for $14.95 or to try and make a mold and pour the slugs
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Can I make this? I do not have a milling machine.
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Unread postAuthor: Gippeto » Sat Dec 06, 2008 5:48 pm

Card stock is like single ply cardboard. The slug you put up, has no sealing surface on the rear. The card stock disk would act as wadding, sealing the bore behind the projectile.

I got my nylon from the machine shop down the street.

I live in Canada eh! (Therefore to perpetuate the myth, I live in an igloo, it's dark 24 hours a day, I eat whale blubber for a snack, I drive a dog team to work, and drink BEER instead of water.) One of those might even be partially true. :wink:

I don't know of anyone selling .745" slugs. Those would be too tight for a muzzle loader anyway. You need some clearance for the air in the bore to escape.

.743" would be pretty close to ideal for a slug diameter. Make sure you can get type K before starting to make slugs or molds.

It will likely cost you as much or more to make the mold. But then, you can make as many slugs as you want. Tire weights are a good source of free lead.

I haven't done a tutorial on casting slugs or mold making. Check the ammo discussion area, and the how to section.

There is something there, I just can't remember where, and I have to run and pick up the wife now.

Edit: Yes you can make a mold for foster slugs with a drill press. You're going to need a drill bit the correct size though, and that will be a bit of a challenge.

You're going to have to file/grind a spade bit.

Do you have a grinder? Preferably a bench grinder.
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Unread postAuthor: jitup » Sat Dec 06, 2008 7:29 pm

Thanks. I think I will final get started soon. ( I am a little behind scehdule but this gun dosen't seem to hard to build after I track down all the parts)

one other thing, for the piston should I use 1 oring to seal or 2? is there any added benifit to having 2 orings?
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Unread postAuthor: jackssmirkingrevenge » Sat Dec 06, 2008 7:31 pm

jitup wrote:one other thing, for the piston should I use 1 oring to seal or 2? is there any added benifit to having 2 orings?


How are you planning on making your piston? A good fitting piston shouldn't even need o-rings, saves you on friction and having to make an equalisation hole.
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Unread postAuthor: Gippeto » Sat Dec 06, 2008 7:42 pm

Jack has a point there. I use o-rings because I want to, not because I need to.

Should you decide to use o-rings, one is enough, and it has to be a "floating" o-ring.

On my pistons, there is a relief in the o-ring groove on the chamber side. This allows the o-ring to function as a check valve.
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Unread postAuthor: jitup » Sat Dec 06, 2008 7:47 pm

all the psiton valves I have looked up had some sort of orings to seal them. This will be the first psiton gun I build (ok I might build a 160psi marble piston just for experience) It would be made of nylon or pvc round stock if I could come across it. If not I was going to pour an acrilic mixture into a Pvc pipe as a round mold, after it was cured I would remove it and shape it to the exact size I need. Is this good or not at all? If you have a helpful link please insert. 8) It will be appreaceated
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Unread postAuthor: Gippeto » Sat Dec 06, 2008 7:49 pm

This one has helped a LOT of people. :)

http://www.spudfiles.com/forums/making- ... t8919.html
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Unread postAuthor: jackssmirkingrevenge » Sat Dec 06, 2008 7:52 pm



*salutes the crowd* thank you, thank you

:roll: :D

And look, no o-rings! :D
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Unread postAuthor: jitup » Sat Dec 06, 2008 8:17 pm

Thanks JSR, you are great. I just have one little question about your set up. what is the bolt and washer do, I just like to know hwo and why things work when I build suff. Is it removed or dose it stay in the piston.
BTW
I will use your methos due to the price of epoxy :D It is CHEAP :D (unless you mean the expensive stuff that costs $50 for a kit)
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