# Mini Cannon



## lpeedin (Mar 10, 2015)

Shoots .177 caliber BBs or pellets. Changed the wheels today to 1" vs the .75" ones I had on during this video. 







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## Andre (Mar 11, 2015)

Now that's cool! I've made a few much smaller ones but weren't nearly as nice, and couldn't get enough powder into them to actually shoot.


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## jim18655 (Mar 11, 2015)

Plans?


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## kvt (Mar 11, 2015)

Looks nice,   and do you have plans, or something.


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## lpeedin (Mar 11, 2015)

Don't have any plans yet, but I am in the process of drawing some up.


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## lpeedin (Mar 11, 2015)

My profile pix is my first attempt.  As you can see, I was losing a lot of energy through the barrel bore & fuse hole due to making them to big.  I will specify hole sizes in the drawings.

BTW: I checked the speed yesterday and it seemed to average between 260 & 280 FPS.


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## kvt (Mar 11, 2015)

When I frist looked at your profile pic,  I thought that was grinder sparks or something,   Now looking close I can see the cannon.   You were loosing a lot of pressure at that time.
what type of metal are you using on the barrel.


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## lpeedin (Mar 11, 2015)

The barrel & carriage are all made from 6061 aluminum.  I shot it 10 times in a row yesterday with just reloading time in between and the barrel didn't even get warm.  I think the aluminum is going to work fine for this.  Should I decide to make something larger, I definitely go for some form of steel.


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## bpratl (Mar 11, 2015)

Neat, how much and what powder did you use? What is the bore ID? Bob


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## kvt (Mar 11, 2015)

I have seen some small ones made out of brass, but not alum.   Although the size of this is not as big as the others I have seen.   If you do decide to schetch up some drawings.  I am very interested.   (wife and animals might not be once done)    what size charge are you using as that did look like a slot of sparks in your profile pic.   
In the vid did it go all the way through the can or just the one side.


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## lpeedin (Mar 11, 2015)

bpratl said:


> Neat, how much and what powder did you use? What is the bore ID? Bob


10-12 grains of FFg or FFFg black powder - BBs and pellets are .177 caliber - a #15 drill bit is .180 and works great.  I got the fuse from cannonfuse.com - if I recall correctly, I used a 1/8" bit for that hole, but I'll need to double check that when I'm back in the shop.  The breach end is drilled and tapped for 1/4 x 20.  I did that to allow clean out in the event of a misfire.  

Insert the fuse
Measure and pour in the powder charge
I use a small amount of cotton as a wad and tamp the powder and wad using a non-metallic ram rod (Q Tip with the cotton removed)
Insert the BB or pellet
Another small amount of cotton to hold the projectile in place.

These cannons are readily available via the internet - this is just my interpretation - and it's a lot more fun to build than buy.


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## lpeedin (Mar 11, 2015)

kvt said:


> I have seen some small ones made out of brass, but not alum.   Although the size of this is not as big as the others I have seen.   If you do decide to schetch up some drawings.  I am very interested.   (wife and animals might not be once done)    what size charge are you using as that did look like a slot of sparks in your profile pic.
> In the vid did it go all the way through the can or just the one side.



If you want a lot of sparks, as in a signal cannon, bore the barrel out larger.  In the profile pix, that barrel was done with a 3/16" bit - .010 over.  The fuse hole was oversize as well, but I don't recall right now exactly what I drilled that with.  For a projectile cannon you want everything as tight as possible.  You get more "bang" by compressing the powder and wad more, but you don't want to do that enough to prevent expulsion through the muzzle. 

When I shot an empty can, it just knocked the can off the table.  I put some water in the can and when I shot above the water level it went through both sides.  In this video the pellet hit below the water line and it only penetrated one side. The MythBusters had a good episode on how fast water will stop a projectile. 


SHOULD I EVER HAVE A MISFIRE, THE FIRST THING I'LL DO IS DROP THE WHOLE CANNON IN A BUCKET OF WATER and give the water plenty of time to soak the powder.


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## lpeedin (Mar 11, 2015)

Here's a video where the projectile hit right at the fluid (beer) line. It went through both sides of the can.








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## lpeedin (Mar 11, 2015)

A couple of image captures from some videos. Note that the wheels of the carriage actually come off the table. In one pix you can see the cotton wad behind the pellet & in another you can see a tiny fire ball about 2/3 the way to the can.









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## lpeedin (Mar 11, 2015)

Some more pix I took in the shop.  Forgot I had these.







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## lpeedin (Mar 11, 2015)

Do you see the mistake I made with the mill?


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## T Bredehoft (Mar 11, 2015)

You mean where you took an extra corner of the step? That 's a witness mark.


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## lpeedin (Mar 11, 2015)

T Bredehoft said:


> You mean where you took an extra corner of the step? That 's a witness mark.


Yea, that's what it is.


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## kvt (Mar 11, 2015)

Ok,   a different monitor changes the whole thing.   had my laptop hooked to a monitor at work all I could see of your pic was the sparks,  Get home on my laptop and I see the whole thing.  I can see the cannon in the picture as well.   I see the miss step.    What is the screw in the end of the barrel for.


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## kvt (Mar 11, 2015)

Forgot to ask,   Are the items on the sides of the cannon machined as part of the barrel or are they screwed on with the screws that hold it to the frame.


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## lpeedin (Mar 11, 2015)

The screw in the back is in case of a mis-fire. I can remove it to clear the full length of the barrel. The trunnions are a single piece of stock held in place by a set screw in the bottom of the barrel. After insertion, the barrel was drilled - this is much simpler than trying to use separate trunnions. 


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## kvt (Mar 14, 2015)

Thanks,  I was wandering if you had used a very large piece and milled the barrel and the trunnions out as one piece.   If so I was going to ask for info on it.   you said they are held in palace by a set screw on the bottoms of the barrel.   So did you drill a hole through the barrel insert the trunnion then drill the bore.    If so would it be better to do a heated press fit,  where you heat the barrel and cool the trunnion in.   Then that would make it almost impossible to remove without having to worry about a set screw.   Just my thoughts on it.


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## bpratl (Mar 15, 2015)

kvt said:


> Thanks,  I was wandering if you had used a very large piece and milled the barrel and the trunnions out as one piece.   If so I was going to ask for info on it.   you said they are held in palace by a set screw on the bottoms of the barrel.   So did you drill a hole through the barrel insert the trunnion then drill the bore.    If so would it be better to do a heated press fit,  where you heat the barrel and cool the trunnion in.   Then that would make it almost impossible to remove without having to worry about a set screw.   Just my thoughts on it.


 Good point, I'm sure that would be an improvement and lessen the chance of an misalignment between the trunnion and bore.


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