2nd Bat
Master sergeant
Posts: 11,813
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Post by 2nd Bat on Feb 18, 2012 15:32:16 GMT -5
I am building a replica M-18 57mm recoiless rifle. These were designed and built during WW2 but had limited service records as they came out so late in the war. They were designed to be a shoulder fired, tripod mounted or vehicle mounted anti tank weapon. Unlike the Bazooka which fired a rocket, these fired more conventional shells but were designed so much of the energy went out the back offsetting the recoil and allowing it to weigh far less than a cannon. They were orignially intended to be issued to airborne troops.
Though technically a WW2 weapon they were far more commonly utilized in the Kroean Conflict and were quite common during Vietnam. Navy SEALS employed them extensively as the LAW proved inadequate for bunker busting or assault use. The Communists reverse engineered the weapon and they were type classified by both the Soviets and the Chinese. They were very prevalent with NVA units and were used in convoy ambushes and lobbed at bases and other area targets. The max range was about 6000 meters so they were effective light artillery in that role.
I have the housing and external appearance items done and am very pleased with the overall look. The weapon mounts nicely on a M1919 tripod. I will set it up to fire NERF rockets using CO2 adapters and a steel encased expansion tube. The launch system as with the actual weapon will all be contained in the shells which I will make several of. The shell, which will house the CO2 cartridge, expansion chamber, release valve and a tube section containing the nerf rocket which slide in the breech and align with an inner barrel in the tube. This will provide the barrel pressure to allow the nerf to fly roughly 300 yards. I have made 90mm recoiless rifles in the past using this method.
It has been a fun project. I will post pictures when I can get some taken and can get them downloaded.
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HornetWSO
Private 1st Class
"We may not have a history, but we have a rendezvous with destiny!"
Posts: 551
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Post by HornetWSO on Feb 18, 2012 20:38:47 GMT -5
This sounds like a great endeavor! I'm looking forward to seeing how you do the shells!
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2nd Bat
Master sergeant
Posts: 11,813
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Post by 2nd Bat on Feb 25, 2012 17:46:53 GMT -5
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2nd Bat
Master sergeant
Posts: 11,813
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Post by 2nd Bat on Feb 25, 2012 18:30:41 GMT -5
Here is another shot showing it in the flat black rather than the Olive drab finish. The weapon was often finished in Olive Drab as well
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CactusDivision
Private
Pvt. 103d Infantry Division 410th Regiment HQ. Company Intelligence and Recon Platoon
Posts: 43
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Post by CactusDivision on Feb 26, 2012 1:03:26 GMT -5
can you make a tutorial for this so we can make our own?
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2nd Bat
Master sergeant
Posts: 11,813
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Post by 2nd Bat on Feb 26, 2012 2:03:37 GMT -5
It's really a lot of sculpturing around hardware you'd buy. I could post a bunch of detailed close up pictures with dimensions I suppose. As for the shells I have been informed that providing precise tutorials about how to make them might not be too wise in a public forum although I got the instructions and ideas from a variety of online sources.
The power generated by the design is such that safe use is not totally assured. I foolishly test fired one in doors. (Okay mom raised an idiot) and watched the foam nerf rocket go into one side of a wood interior door and poke through the other side.) Thankfully I replaced the door before my wife got home. These things can be quite dangerous. Had I not gotten it fixed my wife would have killed me!
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Post by volkssturm on Feb 26, 2012 12:24:37 GMT -5
Great project. Just a bit of trivia I came across when this thread sent me Googling for info on the 57mm. The 4th BCT of the 101st Airborne has taken the grandson of the 57mm, 90mm recoilless rifle, out of mothballs for use in Afghanistan, since the powers that be will only give the Rangers the Carl Gustav. www.combatreform.org/carlgustav.htmMakes a lot of sense. It's a simple, reliable (and cheap) weapon that makes a great bunker buster and also has a pretty wicked anti-personnel round. In my wasted youth we trained with them, but mostly they stayed in the arms room. Anyway, it's a shame the 57mm came in so late in the war. It's one of those weapons, like the M26 pershing tank, that would have made a big difference if it had been ready in time for Normandy. Thnks for the thread, 2nd Bat
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2nd Bat
Master sergeant
Posts: 11,813
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Post by 2nd Bat on Feb 26, 2012 18:35:46 GMT -5
We were in at around the same time but my units 69-77 were always assigned the M72 LAW and the 90mm recoiless rifle which as you said we trained on but they mostly stayed in the arms room. Something heavy to pass around on a long morning run! Every units TO&E probably got by with what they had. The LAW was too wimpy and unreliable and the 90mm too bulky and unwieldly.
The only 57mms I recall seeing were with the brown water NAVY and the SEALS. I saw several captured ones however that were the Chinese variant. They definitely could do a job on an M113!
I had never heard of them actually being in use during WW2 and wasn't even aware they were built during that conflict but apparently the 18th Airborne had them for the Rhine jump (In limited numbers) They probably soldiered into Germany.
Interesting to see them back in service in the sandbox. The size and weight of the weapon makes great sense. Big enough to get the job done but not too bulky. It makes for a cool replica.
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HornetWSO
Private 1st Class
"We may not have a history, but we have a rendezvous with destiny!"
Posts: 551
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Post by HornetWSO on Feb 26, 2012 18:45:22 GMT -5
I understand the construction of the "rounds", but I'm very curious about how you actually fire them once they are in battery?
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2nd Bat
Master sergeant
Posts: 11,813
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Post by 2nd Bat on Feb 29, 2012 15:13:23 GMT -5
There are two approaches to take. One is to use a sprinkler valve which can be electrically opened which allows you to create a trigger. By placing a metal plate in the inner wall of the chamber and a matching metal contact on the shell when in place the circuit contact is made between the tube and the shell. Throw your switch (pull you trigger) and the juice goes to the round opening the sprinkler valve and releasing the pressure in the expansion chamber. This all sounds great in theory and it works...but for me not very reliably. Also the sprinkler valves do not allow for very high pressure or last very long. The approach I take although less realistic to use a metal ball valve. These come in assorted sizes with the larger sizes more effective. (They allow more pressure to be released at once) These ball valve levers protrude from the back of the tube once the round is seated and can be thrown by the assistant gunner at the rear of the weapon upon the command of the gunner. In the case of the 57mm mounted on the tripod the gunner may aim and then activate himself. (I like the crew approach myself) The ball valves are less money, are far more reliable and work very very well. In both cases I charge the weapon with a CO2 cartridge. I do find that the CO2 adapters work well. You place the Co2 cartridge inside the housing and screw the CO2 in until it seats and unloads its contents into the expansion chamber. It takes a minute or so to heat up enough to provide full desired pressure. Once in the expansion chamber the pressure stays for hours (unless you have a slow leak) To be on the "confident" side I recommend players have the shells pre-loaded but with the CO2 un pierced until you move out or you are near the time you expect to fire the weapon. You then screw it in, wait a minute or so and fire. The weapon creates a very loud whooooosh and the nerf rocket or bundle of BBs hurls out. If you use a flechette round of BBs do so in a plunging fire attack as the velocity is actually quite frightening and potentially very dangerous as is a Nerf rocket if fired directly. We use the Nerfs primarily as anti vehicle. They will however dent your vehicle target at close range. When used as indeirect fire artillery we suggest that anyone within 10 meters of a direct ground strike call themselves hit although the practicality of this is dubious at best. When you have access to the howler rockets that make a sound as they fly this goes up considerably as people have a greater awareness that a rocket landed near them. Unfortunately the howlers are hard to source.
Other approaches that work is to have an enclosed expansion chamber that you fill using a shrader valve. These are the brass tire nobs. You thread the pipe and seat the nub insuring a perfect seal. Teflon tape and an exact fit. To do this you'll need a threaded tap that's exactly the right size. With this system you can load the weapon in a variety of ways. You can pump it up with a tire pump. (Takes forever) you can use the squeaze in co2 powered bike accessories or use a compressor or air tank. You then fire either by a sprinker valve or ball valve when ready. Be sure to have a safety release valve, a means to check your pressure and be absolutely certain that all your materials are pressure rated at well above the pressures created. A Co2 cartidge for instance is capable of creating 600 PSI so obviously safety is a concern. Plastic pipe over time, degrades so always greatly exceed the ratings required.
I hope that helps some? These are not weapons to be taken lightly and a great deal of experimenting and practice is required to make them effective on an airsoft field but they add a bunch to an event. What I enjoy about my pre-done shells is they can be used in a variety of weapons. The recoiless rifle, a vehicle main gun, a field piece etc.
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2nd Bat
Master sergeant
Posts: 11,813
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Post by 2nd Bat on Dec 8, 2012 21:01:51 GMT -5
With the newer 40mm mosscart type grenades able to use CO2, the possibilities for crew served rocket launchers goes up dramatically. Trigger mechanisms are much simpler and the power can rival my ball valve set ups. Production time is way way down while the cost of the shells is in line with what the materials costs were for the previous designs I used.
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Post by volkssturm on Dec 8, 2012 22:22:15 GMT -5
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2nd Bat
Master sergeant
Posts: 11,813
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Post by 2nd Bat on Dec 10, 2012 1:06:51 GMT -5
There is an apapter that allows you to use a co2 cartridge to charge the mosscart. It is small and portable and has a pressure guage. Built in. Only the higher quality mosscarts can accomodate the co2. Once filled, the power they generate is amazing.
My plan is to create whole shells that will hold the nerf rocket, the mosscart shell and set them up so they can load through the breech and tie into a section of inner barrel in the recoiless rifle. In this way one could quickly reload and launch rounds.
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savoy6
Private 1st Class
Posts: 428
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Post by savoy6 on Jan 11, 2013 18:57:00 GMT -5
maybe i ought to drag my old one out and set it up for the moscart rounds....it was originally made for the madbull 40mm rounds..
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