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 SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/3/2009 11:16:53 AM
[Last Edit: 12/13/2009 10:48:39 AM by SOC]
THE IMAGE ABOVE IS A PAID ADVERTISEMENT 
20mm on left, 50bmg on the right. The $10,000 price tag seems to be a stumbling block for me. 
Well for $1500 I can pick up a 30mm barrel off of the GAU-8 cannon from an A-10 warthog... 
I want to try to build it into a 30mm rifle. 
What about ammo... 
Here So my biggest problem is finding a muzzle break to tame it. This is gonna be fun. 
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apricotshot
Terminal Lance. It's a joke, get it?
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Posted: 11/3/2009 2:42:15 PM
That's pretty damn cool.
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/3/2009 8:09:20 PM
After a little negotiating with the seller I was able to get the barrel for $1500 including shipping.
This project is officially a GO!!! |
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Posted: 11/4/2009 12:11:18 PM
You and your made machining skills/workshop access... I am soooooo jealous!! But that's pretty sweet.
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apricotshot
Terminal Lance. It's a joke, get it?
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Posted: 11/4/2009 3:05:23 PM
I'm wondering if the recoil is even possible to manage. You're going to have to work some magic besides just a nifty muzzle break. You think you may cut the barrel down any?
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/4/2009 3:54:40 PM
I may go with a single shot shell holder type rifle similar to this one.
Using the 70lb barrel as a base weight, the entire rifle in a similar layout shouldn't be over 100 lbs. I could easily make the lower assembly in two main components (think 1911 slide on a frame) to aid in distributing recoil over a longer period of time. However I have been looking at every 20mm and anti tank rifle I can find. None of them have the greatest muzzle breaks but rely on mass or a semi auto action to distribute recoil. So I've been looking for the best muzzle break I can find. From there I'll come up with other ways to distribute recoil if needed. |
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Posted: 11/6/2009 12:59:53 PM
What about a bolt action that is mounted on a frame via a hydraulic dampener system like a howitzer?
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/7/2009 12:54:46 AM
Originally Posted By logic2:
What about a bolt action that is mounted on a frame via a hydraulic dampener system like a howitzer? I'm hoping a muzzle break like the JP "Tank Break" would be enough. I could use a compressing stock like is used on some shotguns or a stock mounted on a hydraulic dampener. I could also mount the barrel on a rail so it can recoil and build a hydraulic dampener into that design. It will all depend on the pressure curve generated when I test fire this thing with the butt on a pressure sensing plate. |
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JoeCoastie
You have chosen, poorly.
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Posted: 11/7/2009 2:29:39 PM
If I recall correctly, the 25mm bushmaster on the Bradley fighting vehicle exerts a massive amount of recoil. I know that the muzzle brake alone cuts down on something like 5-10k of recoil and the dampening system far more. I can't remember off the top of my head, I haven't been to school for it yet. Anyway I wish you luck in your project but I don't see how you're going to make a 30mm weapon that is somewhat portable with one man and will be able to not break your shoulder at the same time. That's going to be interesting.
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/7/2009 3:30:43 PM
Originally Posted By JoeCoastie:
If I recall correctly, the 25mm bushmaster on the Bradley fighting vehicle exerts a massive amount of recoil. I know that the muzzle brake alone cuts down on something like 5-10k of recoil and the dampening system far more. I can't remember off the top of my head, I haven't been to school for it yet. Anyway I wish you luck in your project but I don't see how you're going to make a 30mm weapon that is somewhat portable with one man and will be able to not break your shoulder at the same time. That's going to be interesting. I figure the worst case is that FULL POWER ammo will be unshootable. 
I may be stuck with using a reduced load. Or firing it mounted to something. In the end it will at least look cool hanging in the shop. |
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runs-with-scissors
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Posted: 11/7/2009 4:08:40 PM
if you are going to build it - go all the way (mag fed) it may be more PITA but if your going to all that trouble already, might as well build a cadillac.
good luck on the build, i would offer a few ideas (some may work some may not) - bipod that is set with the feet at a 45 degree angle back towards the shooter (maybe spike feet if you are prone on soft ground?) - maybe even a tripod with a reinforced back leg to handle the recoil - with the weight already high, a hydrolic dampened stock could be nice - or a stock that allows the rifle to slide on a rail (hydrolic or spring dampened?) while having the cheek weld stay still. |
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/7/2009 4:17:38 PM
Originally Posted By runs-with-scissors:
if you are going to build it - go all the way (mag fed) it may be more PITA but if your going to all that trouble already, might as well build a cadillac. good luck on the build, i would offer a few ideas (some may work some may not) - bipod that is set with the feet at a 45 degree angle back towards the shooter (maybe spike feet if you are prone on soft ground?) - maybe even a tripod with a reinforced back leg to handle the recoil - with the weight already high, a hydrolic dampened stock could be nice - or a stock that allows the rifle to slide on a rail (hydrolic or spring dampened?) while having the cheek weld stay still. Building it as a single shot, is something I can do right now. This would also stll me in the shortest period of time weather or not this project is doable. As it is my lathe isn't large enough to fit the slab of round stock needed for a mag feed receiver. The cost of having someone else make that part to the specs I need... I might as well send the barrel to Anzio. No reason I couldn't build a repeater action later. As for your other ideas I have thought the same things and all are options on the table. For now I'm waiting on the barrel to show up so I can start cutting metal. |
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Skillshot
Man
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Posted: 11/7/2009 4:19:50 PM
Originally Posted By SOC:
I figure the worst case is that FULL POWER ammo will be unshootable.
I may be stuck with using a reduced load. Or firing it mounted to something. In the end it will at least look cool hanging in the shop. Drill a few ports for direct impingement gas tubes which are routed under the receiver, through the stock, and back behind the shooter, so it will be like a recoilless rifle. |
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/7/2009 4:56:37 PM
Originally Posted By Skillshot:
Originally Posted By SOC:
I figure the worst case is that FULL POWER ammo will be unshootable.
I may be stuck with using a reduced load. Or firing it mounted to something. In the end it will at least look cool hanging in the shop. Drill a few ports for direct impingement gas tubes which are routed under the receiver, through the stock, and back behind the shooter, so it will be like a recoilless rifle. If I was after a recoilless rifle I'd build it in an Bazooka layout with the chamber and some barrel behind my shoulder and drill ports at a degree angle around the barrel just past the chamber. I think I'd build it as a carriage mounted AT gun first, like a slightly smaller version of this 37mm.  |
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Posted: 11/9/2009 5:55:46 AM
[Last Edit: 11/9/2009 5:56:43 AM by The_Emu]
Originally Posted By SOC:
Originally Posted By Skillshot:
Originally Posted By SOC:
I figure the worst case is that FULL POWER ammo will be unshootable.
I may be stuck with using a reduced load. Or firing it mounted to something. In the end it will at least look cool hanging in the shop. Drill a few ports for direct impingement gas tubes which are routed under the receiver, through the stock, and back behind the shooter, so it will be like a recoilless rifle. If I was after a recoilless rifle I'd build it in an Bazooka layout with the chamber and some barrel behind my shoulder and drill ports at a degree angle around the barrel just past the chamber. I think I'd build it as a carriage mounted AT gun first, like a slightly smaller version of this 37mm. http://www.chakoten.dk/images/dan_army_2a_2043.jpg A friend here in AK is building a 30mm with a GAU barrel. I've bought a barrel too. Im not sure if i have the skills to build it like i want but im gonna try. What i want is a falling block action, single shot. (like a big ruger No1) It will be mounted on a tripod or a wheeled carage. |
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/9/2009 6:14:36 AM
Originally Posted By The_Emu:
Originally Posted By SOC:
Originally Posted By Skillshot:
Originally Posted By SOC:
I figure the worst case is that FULL POWER ammo will be unshootable.
I may be stuck with using a reduced load. Or firing it mounted to something. In the end it will at least look cool hanging in the shop. Drill a few ports for direct impingement gas tubes which are routed under the receiver, through the stock, and back behind the shooter, so it will be like a recoilless rifle. If I was after a recoilless rifle I'd build it in an Bazooka layout with the chamber and some barrel behind my shoulder and drill ports at a degree angle around the barrel just past the chamber. I think I'd build it as a carriage mounted AT gun first, like a slightly smaller version of this 37mm. http://www.chakoten.dk/images/dan_army_2a_2043.jpg A friend here in AK is building a 30mm with a GAU barrel. I've bought a barrel too. Im not sure if i have the skills to build it like i want but im gonna try. What i want is a falling block action, single shot. (like a big ruger No1) It will be mounted on a tripod or a wheeled carage. Be sure to keep us updated with pics as you go. We can share info on design finding ammo etc. |
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/9/2009 6:14:39 AM
[Last Edit: 11/9/2009 11:02:13 PM by SOC]
Double tap
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jestertoo
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Posted: 11/9/2009 10:06:27 PM
Originally Posted By SOC:
Originally Posted By The_Emu:
A friend here in AK is building a 30mm with a GAU barrel. I've bought a barrel too. Im not sure if i have the skills to build it like i want but im gonna try. What i want is a falling block action, single shot. (like a big ruger No1) It will be mounted on a tripod or a wheeled carage. Be sure to keep us updated with pics as you go. We can share info on design finding ammo etc. SOC, I PM'ed you the email address of the guy in AK that Emu speaks of. He has lots of pictures. J |
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4schitzangiggles
"Our Lives, our fortunes, our sacred honor...
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Posted: 11/10/2009 8:52:18 PM
where does one find the empties for reloading this beast!?
Half a can of powder for one round? And does each round have to have the DD tax stamp as well? Thanks BTW, way fricken cool! |
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/11/2009 3:20:35 AM
Originally Posted By 4schitzangiggles:
where does one find the empties for reloading this beast!? Bigsky Surplus Half a can of powder for one round? I'm starting my reloads using half a shell full of Trailboss. (Comes in 8lb jugs) I'll work up from there. And does each round have to have the DD tax stamp as well? Only if the projo contains explosive. (Live rounds cost between $70 for TP to $120 and up for HEI) Training projos, penetrators, and sabot rounds are non DD. I plan on machining my own aluminum, copper, brass and steel projos on my lathe. The projos use a plastic driving band so the "bullet" itself never touches the rifling hence why steel is fine. Thanks BTW, way fricken cool! |
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Posted: 11/11/2009 11:22:40 AM
[Last Edit: 11/11/2009 11:24:21 AM by mwarnick1]
I have to thank you guys for resurrecting my interest in my cannon build. It's been a sloooooow process. I got stopped for a couple years because I couldn't find a heat treater in Alaska to treat my receiver. I ended up using Seattle Heat Treaters. They worked out really well and the receiver is currently on it's way back to Alaska.
Here's some info to get the questions going. I'm happy to share info as when I started this it took me a long time to find reliable info. I started out intending to build a typical cannon breech but got hung up on headspace and machining complexity issues. I ended up going with a screw type breech. It's easy to machine and the headspace gets reset for every shot. It took quite a bit of calling around to get the right sized chunk of annealed 4140. IIRC it came out of a foundry in Ohio. My original thread design was only marginally safe with full-power 30mm GAU loads. I've since redesigned and recut the threads significantly larger (buttress threads this time too) in order to amp up the safety margin. I did shoot the original design with it strapped to a tire and a long pull cord. Common wisdom is that reloading aluminum cases is a really bad idea so you might want to take this into consideration for your build. I mitigated this by oversizing the design and drilling a gas relief hole in the receiver in case the aluminum case lets go. I love the Trailboss powder idea. I was unsure what I was going to use once my superslow surplus powder was gone. Corrosive black powder wasn't the best solution. I have a couple hundred T328 30mm projectiles to shoot and then will lathe turn projo's after that. I bought a 37mm AT gun replica kit from Mac Replicas. I'll use this as a host to build my 30mm GAU towed gun. http://www.macreplicas.com/ I don't have time to post the pictures (jury duty and work is slamming me) but the folks that have my pictures are welcome to post them. Good luck! Matt |
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SOC
"Sarg... I'm Crazy, not stupid."
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Posted: 11/11/2009 12:15:54 PM
Originally Posted By mwarnick1:
I have to thank you guys for resurrecting my interest in my cannon build. It's been a sloooooow process. I got stopped for a couple years because I couldn't find a heat treater in Alaska to treat my receiver. I ended up using Seattle Heat Treaters. They worked out really well and the receiver is currently on it's way back to Alaska. Here's some info to get the questions going. I'm happy to share info as when I started this it took me a long time to find reliable info. I started out intending to build a typical cannon breech but got hung up on headspace and machining complexity issues. I ended up going with a screw type breech. It's easy to machine and the headspace gets reset for every shot. It took quite a bit of calling around to get the right sized chunk of annealed 4140. IIRC it came out of a foundry in Ohio. My original thread design was only marginally safe with full-power 30mm GAU loads. I've since redesigned and recut the threads significantly larger (buttress threads this time too) in order to amp up the safety margin. I did shoot the original design with it strapped to a tire and a long pull cord. Common wisdom is that reloading aluminum cases is a really bad idea so you might want to take this into consideration for your build. I mitigated this by oversizing the design and drilling a gas relief hole in the receiver in case the aluminum case lets go. I love the Trailboss powder idea. I was unsure what I was going to use once my superslow surplus powder was gone. Corrosive black powder wasn't the best solution. I have a couple hundred T328 30mm projectiles to shoot and then will lathe turn projo's after that. I bought a 37mm AT gun replica kit from Mac Replicas. I'll use this as a host to build my 30mm GAU towed gun. http://www.macreplicas.com/ I don't have time to post the pictures (jury duty and work is slamming me) but the folks that have my pictures are welcome to post them. Good luck! Matt Where did you get your projos and shells? What is your reloading process? |
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Posted: 11/11/2009 3:19:15 PM
[Last Edit: 11/11/2009 3:34:29 PM by mwarnick1]
Where did you get your projos and shells? What is your reloading process? Projectiles came from River Valley Ordnance years ago before the owner passed away (I think that's the story anyway). The shells came from misc internet sources. They're pretty easy to find with a search on the main auction sites. I'm planing on having the cases nickel plated. I'm not sure if it will help make them more robust or not but I don't think it can hurt? I have a few GAU primers but plan to sleeve the cases for 50BMG primers once these run out. My reloading tools are crude and don't involve resizing. My screw type action is strong enough to push the unsized cases into the chamber. 1) Use a rod and a jack/press to beat/press out the existing primer and 'initiator' tube. Some of these are amazingly tight. 2) Refill initiator tube with 1F black powder and cap both ends. I forget what I used but it was probably some type of silicone sealant. 3) Insert initiator tube and press the primer into place. I used a rod that fit over the initator tube and stuck out the end of the case to put the pressure on the bottom of the case. I then used my floor jack and bottom of an armored car to press the primer and initiator into place. 4) Load powder. I've used full cases of 1F BP and also full cases of superslow surplus powder. 5) Insert projectile 6) 'Crimp' projectile with a modified pipe cutting tool. Similar to this one but a cheap version: http://www.homedepot.com/h_d1/N-5yc1vZ1xr5/R-100001470/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053 I replaced the sharp cutting wheel with a donut shaped rounded wheel. This is used to force the case into the crimp groove on the projectile. Pretty crude, eh? I hope this helps, Matt |
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Posted: 11/11/2009 3:26:28 PM
Here's a great book to review before starting a build. It's way more technical than I am but I liked looking at the pretty sketches.
 I loaned it to my mechanical engineering buddy who helped validate my design and strength calculations. I reworked my plan until he said 'I'd stand next to it when it went off':
Cannon Design Book |
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Posted: 11/11/2009 9:25:25 PM
Originally Posted By mwarnick1:
Where did you get your projos and shells? What is your reloading process? Projectiles came from River Valley Ordnance years ago before the owner passed away (I think that's the story anyway). The shells came from misc internet sources. They're pretty easy to find with a search on the main auction sites. I'm planing on having the cases nickel plated. I'm not sure if it will help make them more robust or not but I don't think it can hurt? I have a few GAU primers but plan to sleeve the cases for 50BMG primers once these run out. My reloading tools are crude and don't involve resizing. My screw type action is strong enough to push the unsized cases into the chamber. 1) Use a rod and a jack/press to beat/press out the existing primer and 'initiator' tube. Some of these are amazingly tight. 2) Refill initiator tube with 1F black powder and cap both ends. I forget what I used but it was probably some type of silicone sealant. 3) Insert initiator tube and press the primer into place. I used a rod that fit over the initator tube and stuck out the end of the case to put the pressure on the bottom of the case. I then used my floor jack and bottom of an armored car to press the primer and initiator into place. 4) Load powder. I've used full cases of 1F BP and also full cases of superslow surplus powder. 5) Insert projectile 6) 'Crimp' projectile with a modified pipe cutting tool. Similar to this one but a cheap version: http://www.homedepot.com/h_d1/N-5yc1vZ1xr5/R-100001470/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053 I replaced the sharp cutting wheel with a donut shaped rounded wheel. This is used to force the case into the crimp groove on the projectile. Pretty crude, eh? I hope this helps, Matt 
You should post this over on the 'files...this is pure WECSOG goodness right here. Bravo brave sir! |
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Posted: 11/12/2009 10:18:10 AM
You should post this over on the 'files...this is pure WECSOG goodness right here. Bravo brave sir! I've since sold my armored car so I guess I'll have to come up with a more professional set-up in the future (or wait outside wallmart with my floorjack for a Brinks truck to show up to collect money?). The risk is relatively low. I did wear my eye and ear protection while pressing in the primer though. Now that you point it out this does sound pretty dang strange. I wish I would have taken pictures to document my reloading set-up
Matt |
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