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KopperBess - My first copper pneumatic
Posted: Tue Feb 24, 2009 7:20 pm
by Big-E
Hello all, Here is my first submission to spudfiles. the KopperBess (Bess as in Brown Bess; Just another old term for a smoothbore) some folks were really wanting to see what I made, so I snapped some quick pics and decided to tell you about it sooner rather than later.
I sort of freestyled this gun, trying to figure chamber sizes and such. so I've built a modular testbed where I can change out chamber and barrel types.
Currently it's got a 1/2" copper barrel at 24" long. chamber chamber is currently 3/4", although I had other sizes and lenghts on it before. I also have a full 3/4" ball valve in-line to vary chamber size when shooting. I can use it for multiple shots with one fill for plinking, or high power by using the full chamber for one shot. it's sort of an ever evolving work in progress.
The firing valve is a full 1/2" ball valve toggled by a spring. the valve is held closed by resting against a leaf-spring like sear. only a little squeeze on the "trigger spring" is needed to release the simple mechanism. I cock the lever forward and reengage the mechanism with the aid of an additonal little knob attatched to the lever.
I've also integrated a shock pump so it's very mobile. for major shooting, I use a little 12 volt compressor that quickly fills the gun up to 250 PSI.
Normally used around 150 psi or so, highest I've brought it to to date is 300. shoots great and accuracy is improving as I dial it in. I use marbles and custom pellets (more like saboted lead sinkers) that are a bit more accurate.
Any questions or comments, feel free to post them.

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Posted: Tue Feb 24, 2009 7:24 pm
by daberno123
Sounds great. Can't wait to see those pictures... *hint*
Posted: Tue Feb 24, 2009 7:25 pm
by sputnick
you snapped pictures, But did not add them to the post?
Sounds like a really decent gun, I look forward to seeing it!
damn it, not first post after all

Posted: Tue Feb 24, 2009 7:26 pm
by Big-E
yea, having trouble with that... I attatched them, but they're not showing up. they're the correct size... Meh. I'll see what I can do about posting them remotely!
THis happens alot with us newbs I suppose...
Posted: Tue Feb 24, 2009 7:37 pm
by jonnyboy
Big-E wrote:yea, having trouble with that... I attatched them, but they're not showing up. they're the correct size... Meh. I'll see what I can do about posting them remotely!
THis happens alot with us newbs I suppose...
I find if your uploading multiple pictures its easier to use photo bucket or similar things. When you upload the picture it will give you some codes copy and paste
hot link for forums 1 .
Posted: Tue Feb 24, 2009 7:53 pm
by Big-E
fixed my original post guys... images work now
Thanks for the advice JonnyBoy
Posted: Tue Feb 24, 2009 8:04 pm
by sputnick
Wow, that looks great!
Any chance you could get a better picture of the front sight? just for me
Looks very pro, and powerful, although I don't know how many shots you would get from that tank.
Posted: Tue Feb 24, 2009 8:18 pm
by Big-E
Yea, I'll take a couple more pics tomorrow, I am charging the batteries at the moment for my camera.
The barrel is tipped with a small stopless coupler, with a slight offset from the end of the barrel. behind that, I used a copper pipe tacking strip, shaped it to the profile I wanted. Then I just soldered it all into place, and filed the front sight to shape. I then crowned the barrel's muzzle with a nice smooth taper. I'll be sure to take pics of it for you.
I can get about three shots off if I close the chamber valve before each shot, and leave it open for the third. It's also nice because I simply top off the chamber after every shot with about 10 pumps or so (when plinking or destroying cans). I close the firing valve, equalize the chamber with the chamber valve, close the chamber valve and pump. as you know, it's easier and quicker to fill a small chamber. by filling the entire chamber to at least 250 PSI and topping off before each shot, I can get off a lot more shots with little effort.
I've also thought of making a chamber out of 2" copper, and fitting that as the auxilliary. because it's threaded, I can put basically any size chamber I want on it.
Posted: Tue Feb 24, 2009 8:43 pm
by jonnyboy
Looks like you could upgrade to a qev or piston valve.hint hint
Posted: Tue Feb 24, 2009 8:56 pm
by Big-E
ah, yes I could. Of course, I think I'm going to be using a qev on my next project gun. starting from scratch.
That's not to say I can't add a qev, or a piston valve to this one. Or a breech loading barrel, or a golfball barrel. I intentionally made it so I could make individual components and swap them.
The only reason I may start from scratch on my QEV concept is the transfer port on the current model, which is sort of a gooseneck created by the 1/2" elbow. my next model would have the primary firing chamber in-line behind the barrel.
I also take a lot of inspiration from the old PCP guns like the Lukens air rifle. I didn't want my first effort to be too ambitious.

Posted: Tue Feb 24, 2009 8:56 pm
by sputnick
That is really smart, and looks great, really reminds me of the muzzle break on the thompson...

Posted: Tue Feb 24, 2009 9:03 pm
by SpudsMcGee
Cool, it does look like the Thompson.
Posted: Tue Feb 24, 2009 11:05 pm
by tape fist
That's a great looking gun and what gauge of wire did you use to make the chain mail.
Posted: Wed Feb 25, 2009 12:52 am
by starman
Love the chainmail...
I like the integrated and handy hand pump...you see that occasionally but less often than you might think. Well done there.
Can I assume the metal strapping is a standoff for the spring?
Overall nice copper cannon!!
Posted: Wed Feb 25, 2009 2:26 am
by cheeseboy
This is a great gun

I can't think of anything you've missed out, and you included a safety (the first thing I check for in a spring loaded ball valve, I had a bad experience but that's another story). I think that it wouldn't hard to turn this steam-punk, it looks so good already! A pic down the sights would be cool too. Is the bent metal bar used to hold the valve then you move it to fire? if its not, can you please explain how it works?