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Posted: 1/25/2021 11:24:45 PM EDT
[#1]
Quote HistoryQuoted: Elmer Keith talked about cartridges with huge powder columns having a tube in the middle running from the primer to near the bullet base. This ignited the powder at the front of the column and just gas and bullet were pushed down the throat and pushing the powder column to the rear. I can't remember what he called this sort of set up though. I think her experimented with it for one of his Wildcats like the .30-.378 maybe. Sounds like a flash tube. |
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Posted: 1/25/2021 11:26:03 PM EDT
[#2]
Quote HistoryQuoted: Anzio Ironworks? I was gonna say this. They came up with the 20-.50 caliber, they should be able to put you onto the right track. I wanna shoot it. |
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Posted: 1/25/2021 11:26:11 PM EDT
[#3]
I hope you've budgeted for the 200 yard gel block instillation.
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Posted: 1/25/2021 11:34:51 PM EDT
[#4]
Quote HistoryQuoted: Understood. This all depends on OP's design criteria though. A hilariously long barrel might be acceptable. I agree though, the bottleneck issue is a big stumbling block, though I'm not familiar with it on this massive of a scale. Quote HistoryQuoted: Quoted: Quoted: Quoted: Quoted: Quoted: Daddy like Speed on something like that 4600-5200 fps? The goal is an elongated tungsten .50 projectile weighing 1500 grains and spitting out at 4600fps. I understand that will have relatively short barrel life, but I'm ok with that. Look up 14.5x114mm...and the problems with powder. A case like you describe would be akin to a 50cal necked down to 30cal; very, very hard to get the powder gases out the small throat, leading to very high case pressures, unless the powder is sloooooooow. 14.5 powder looks like rabbit food. Faster powders are probably doable, but total energy will have to held down to avoid causing a nuclear fusion reaction inside the case (defeating the purpose of the big brass hull) If it can be done, Anzio is probably the go-to With a long enough barrel, a slower powder probably might work. Problem would be sourcing it. There's always the V3 option too. Despite the guns of Mimoyecques never shelling England, the concept was sound, albeit horribly impractical. Length doesn't matter; the neck is literally the bottleneck. Now, if you do find a slow enough powder to fill the case AND keep pressures reasonable, yeah, you'd need a big honkin' propeller shaft of a barrel to actually exploit it. 25mm has a long barrel, a fat projectile, and moderate chamber pressures, and it STILL breathes fire. Understood. This all depends on OP's design criteria though. A hilariously long barrel might be acceptable. I agree though, the bottleneck issue is a big stumbling block, though I'm not familiar with it on this massive of a scale. I think it's basically a limitation of nitrocellulose, itself. At high pressures and large volumes, it basically starts acting explosive; imagine trying to contain a block of RDX high explosive in a Mauser action --the muzzle-end had better not have anything getting in the way of that blast wave. Similarly, big nitrocellulose rounds end up being straight walled, or nearly so. The other issue with super long barrels...droop. A KPV barrel in 14.5 is like 5ft long, and it 'only' has 2x the energy of a 50bmg. You may need like a 12ft flagpole to properly exploit this beast, and good luck trying to control barrel whip or sag without turning it into a howitzer! If you're going to make a towed artillery piece that's crew served...why not rock a quad-KPVT ZPU-4? Pretty sure no one will want to argue with you about tax stamps, lol. This is why my anti-material project is chambered in 338 Norma, and will be a very man-portable bullpup scheme based on the SS-41. The record of the PTRS vs. the PTRD shows that light & mobile is a far better approach than massive & powerful. Given how reliant modern armor is on sensors, an anti-material rifle doesn't need to be super powerful, but it does need to be precise (and modern optics enable them to reach out much farther than the iron-sighted guns of yore) |
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Posted: 1/25/2021 11:36:50 PM EDT
[#5]
Quoted: Pac Nor can't or won't do it. Anyone have any ideas? And yes- I'm looking at necking down a bushmaster cannon round to .50 caliber.   |
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Posted: 1/25/2021 11:37:02 PM EDT
[#6]
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Posted: 1/25/2021 11:37:28 PM EDT
[#7]
Quote HistoryQuoted: The other issue with super long barrels...droop. A KPV barrel in 14.5 is like 5ft long, and it 'only' has 2x the energy of a 50bmg. You may need like a 12ft flagpole to properly exploit this beast, and good luck trying to control barrel whip or sag without turning it into a howitzer! What about a structured barrel? |
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Posted: 1/25/2021 11:44:17 PM EDT
[#8]
Quote HistoryQuoted: In what part of the state do you plan to hunt deer? Apparently the whole state and just from one spot. |
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Posted: 1/25/2021 11:47:36 PM EDT
[#9]
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Posted: 1/25/2021 11:48:08 PM EDT
[#10]
Quote HistoryQuoted: I'd reach out to Mark Serbu. https://serbu.com/contact-us/ If they can't do it, I'd bet they can tell you of someone who can. This is what I was thinking |
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Posted: 1/25/2021 11:48:08 PM EDT
[#11]
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Posted: 1/25/2021 11:48:30 PM EDT
[#12]
I would just bake a barrel in 50bmg that screws on to a larger sleeve that can be locked into the breach bolt housing.
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Posted: 1/25/2021 11:51:04 PM EDT
[#13]
That's what I was thinking but not fast enough for what OP wants to do from the sounds of it.
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Posted: 1/25/2021 11:52:28 PM EDT
[#14]
Quote HistoryQuoted: I would just bake a barrel in 50bmg that screws on to a larger sleeve that can be locked into the breach bolt housing. That was my first thought. Two part barrel. |
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Posted: 1/25/2021 11:54:05 PM EDT
[#15]
It could be done with a 50 BMG EPVAT test barrel.
Try Bill Wiseman. |
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Posted: 1/25/2021 11:57:21 PM EDT
[#16]
2.06" is the biggest I see and I doubt that is big enough. Anyone have the actual cartridge dimensions? I see length and some other measurements but didn't see the bolt face size in my quick search. |
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Posted: 1/25/2021 11:59:58 PM EDT
[#17]
I'm glad you're doing what you want and all. But it seems a terrible waste. So many questions.
What would you use for powder? |
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Posted: 1/26/2021 12:01:13 AM EDT
[#18]
Quote HistoryQuoted: bro are you trying to build an anti-tank rifle or something? Quote HistoryQuoted: bro are you trying to build an anti-tank rifle or something? Pretty sure that goes well beyond trying  Quoted: In what part of the state do you plan to hunt deer? From his roof? "yes". The answer is "yes" |
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Posted: 1/26/2021 12:03:58 AM EDT
[#19]
Quote HistoryQuoted: my math just put your project at 70,496 ft-lbs of energy.... hell yeah brother, 'merica that shit up.  Attached File |
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Posted: 1/26/2021 12:04:05 AM EDT
[#20]
Ballistic advantage. If you ate willing to pay.
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Posted: 1/26/2021 12:07:06 AM EDT
[#21]
Quote HistoryQuoted: What's the plan for the sabot, or will the tungsten just be a core? Also, holy shit at the 3.4 ounce projectile weight.
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Posted: 1/26/2021 12:12:14 AM EDT
[#22]
Quote HistoryQuoted: 2.06" is the biggest I see and I doubt that is big enough. Anyone have the actual cartridge dimensions? I see length and some other measurements but didn't see the bolt face size in my quick search. 38mm head diameter. |
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Posted: 1/26/2021 12:12:23 AM EDT
[#23]
Would it be more cost effective just to buy a bunch of SLAP? Because I suspect that would be the case, especially considering you can also lob other sorts of rounds.
I can't think of anything you'd actually need that sort of projectile and velocity on that you'd want to mess with from the front and/or at longer rangers where you'd need that level of performance. |
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Posted: 1/26/2021 12:15:33 AM EDT
[#24]
Quote HistoryQuoted: From his roof? "yes". The answer is "yes" Earlier I planned to move over a grain silo and install a rotating top. The crane rental was excessively expensive to disassemble the old one made of concrete tinker-toys. Still a good plan. Would work a lot better in some flat land. I'm sure OP already has this worked out. |
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Posted: 1/26/2021 12:15:40 AM EDT
[#25]
Call Bartlein, Frank was saying they made a run of 20mm barrels for a private customer.
They also came out with a new steel 400MODBB which seems like a real deal 50-100% increase in bbl life. |
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Posted: 1/26/2021 12:29:33 AM EDT
[#26]
Quote HistoryQuoted: Would it be more cost effective just to buy a bunch of SLAP? Because I suspect that would be the case, especially considering you can also lob other sorts of rounds. I can't think of anything you'd actually need that sort of projectile and velocity on that you'd want to mess with from the front and/or at longer rangers where you'd need that level of performance. Like NFA hand grenades, sometimes you just have to do things to prove you can. Also, shooting a wild hog with the "25(mm) Blackout" (yes, it is a misnomer) from the turret of an armored vehicle is > .50 caliber action. |
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Posted: 1/26/2021 12:30:55 AM EDT
[#27]
Quote HistoryQuoted: Why would I do that when I already have NFA Carl Gustav and RPG destructive device projects ongoing? Quote HistoryQuoted: Quoted: bro are you trying to build an anti-tank rifle or something? Why would I do that when I already have NFA Carl Gustav and RPG destructive device projects ongoing? RPG 2 or 7?
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Posted: 1/26/2021 12:31:26 AM EDT
[#28]
Ben,
Heads up on the I.M. 
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Posted: 1/26/2021 12:31:53 AM EDT
[#29]
Quote HistoryQuoted: Like NFA hand grenades, sometimes you just have to do things to prove you can. Also, shooting a wild hog with the "25(mm) Blackout" (yes, it is a misnomer) from the turret of an armored vehicle is > .50 caliber action. I’m referenced in this post, and I’m offended! |
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Posted: 1/26/2021 12:32:10 AM EDT
[#30]
Quote HistoryQuoted: RPG 2 or 7? Yes. |
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Posted: 1/26/2021 12:33:42 AM EDT
[#31]
Quote HistoryQuoted: In what part of the state do you plan to hunt deer? All parts. From his driveway. |
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Posted: 1/26/2021 12:34:47 AM EDT
[#32]
Quote HistoryQuoted:I understand that will have relatively short barrel life, but I'm ok with that. |
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Posted: 1/26/2021 12:40:19 AM EDT
[#33]
Maybe you can get a 50 caliber sleeve for the 25-mm Bushmaster?
The thing Elmer Keith and friends did in the past was called front ignition and it's very picky about complete powder loadings as opposed to flash tubes which are extremely common in mid to large caliber weapons |
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Posted: 1/26/2021 12:41:14 AM EDT
[#34]
Quote HistoryQuoted: Yes. Quote HistoryQuoted: Quoted: RPG 2 or 7? Yes. Are you'll rewelding the tubes or having new ones made? I know an arfcommer sold some RPG2 tubes a while back. |
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Posted: 1/26/2021 12:43:11 AM EDT
[#35]
Quote HistoryQuoted: Are you'll rewelding the tubes or having new ones made? I know an arfcommer sold some RPG2 tubes a while back. New RPG-2 rewelded RPG-7 tube |
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Posted: 1/26/2021 12:48:04 AM EDT
[#36]
Man I love being a gun head. Awesome thread is awesome. That is all!
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Posted: 1/26/2021 1:09:24 AM EDT
[#37]
Quote HistoryQuoted: New RPG-2 rewelded RPG-7 tube Quote HistoryQuoted: Quoted: Are you'll rewelding the tubes or having new ones made? I know an arfcommer sold some RPG2 tubes a while back. New RPG-2 rewelded RPG-7 tube Have you'll tested the booster charge on the rewelded RPG7? |
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Posted: 1/26/2021 1:11:36 AM EDT
[#38]
Quote HistoryQuoted: 38mm head diameter. Quote HistoryQuoted: Quoted: 2.06" is the biggest I see and I doubt that is big enough. Anyone have the actual cartridge dimensions? I see length and some other measurements but didn't see the bolt face size in my quick search. 38mm head diameter. I can't remember the exact numbers but I am thinking 2.5" would be minimum and maybe still inadequate. Definitely want to figure all that out first. Random internet fact I found in 10 seconds so it must be true I don't know what the working pressure of the .22 WMR is, so I can't give you a calculated value. But the convention is to have chamber walls 2/3 of the diameter of the cartridge for high pressure applications so that should be adequate for a .22 WMR. So assuming the diameter of the cartridge is .250", the wall thickness should be .167" and the overall diameter should be at least .583". |
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Posted: 1/26/2021 1:14:18 AM EDT
[#39]
Quote HistoryQuoted: Like NFA hand grenades, sometimes you just have to do things to prove you can. Also, shooting a wild hog with the "25(mm) Blackout" (yes, it is a misnomer) from the turret of an armored vehicle is > .50 caliber action. True, true. |
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Posted: 1/26/2021 1:33:37 AM EDT
[#40]
NVM
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Posted: 1/26/2021 2:01:32 AM EDT
[#41]
Quote HistoryQuoted: Maybe you can get a 50 caliber sleeve for the 25-mm Bushmaster? The thing Elmer Keith and friends did in the past was called front ignition and it's very picky about complete powder loadings as opposed to flash tubes which are extremely common in mid to large caliber weapons Back then, double based propellants, and deterrent coatings weren't real mature tech yet, and surface area was much more of a concern to consistent and reliable burn rate under pressure. Roy Weatherby got around the matter with plenty of freebore, and it's still used, but controlled freebore for the crazy high pressure stuff the .Mil tinkers with. The problem Ben is going to run into, is gaining volume/time to keep bolt thrust and pressure curve sane, using an off the shelf/surplus propellant. It ain't like mortals can call up Alliant, and order a gourmet powder to spec., without a freight train sized purchase order. Crazy overbore stuff can get all kinda pressure curve weird, without specialized coatings mere mortals don't have access to. Modifying 30mm cases with ignition tubes could be fun to tinker with, though I'm not sure it would reduce chamber pressures and Bolt thrust as much as a controlled free bore. I'm curious to see what direction Ben ends up going. It ain't like I have the $$$ to tinker with the impractical stuff that is pure fun! |
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Posted: 1/26/2021 2:09:23 AM EDT
[#42]
Quote HistoryQuoted: Motherfuckers don't even read what I type. https://web.archive.org/web/20150108034204im_/http://www.anzioironworks.com/Photos/Anzio-big-bore-selection1.jpg *ahem* Anzio Ironworks probably has some experience. |
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Posted: 1/26/2021 2:22:21 AM EDT
[#43]
Quote HistoryQuoted: Sounds like a flash tube. Quote HistoryQuoted: Quoted: Elmer Keith talked about cartridges with huge powder columns having a tube in the middle running from the primer to near the bullet base. This ignited the powder at the front of the column and just gas and bullet were pushed down the throat and pushing the powder column to the rear. I can't remember what he called this sort of set up though. I think her experimented with it for one of his Wildcats like the .30-.378 maybe. Sounds like a flash tube. Yes! I believe so. It's been a long time since I've read much of what EK did. |
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Posted: 1/26/2021 2:25:28 AM EDT
[#44]
Quote HistoryQuoted: Maybe you can get a 50 caliber sleeve for the 25-mm Bushmaster? The thing Elmer Keith and friends did in the past was called front ignition and it's very picky about complete powder loadings as opposed to flash tubes which are extremely common in mid to large caliber weapons I just remembered him doing that after l made the previous tongue- in- cheek post. But it's been several years since I've read much of his exploits and couldn't remember why he didn't use it more. Thanks. |
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Posted: 1/26/2021 2:34:24 AM EDT
[#45]
OP-
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Posted: 1/26/2021 4:56:03 AM EDT
[#46]
 It's a .50 out of a 25mm. It shoots through 
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Posted: 1/26/2021 9:01:17 AM EDT
[#47]
So my coworkers husband is a gun Smith and they do custom gun smithing including some barrels. They did a design in a 36" .50 shooting non-sabot tungsten rounds and the barrel lasted 50 rounds before the rifling was gone.
But they could probably do it. If you want the info I could ask. |
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Posted: 1/26/2021 9:12:08 AM EDT
[#48]
Quote HistoryQuoted: Ahem. They don't do over 20mm. And the ballistics of their 20/50 are too weak. Quote HistoryQuoted: Quoted: Motherfuckers don't even read what I type. https://web.archive.org/web/20150108034204im_/http://www.anzioironworks.com/Photos/Anzio-big-bore-selection1.jpg *ahem* Anzio Ironworks probably has some experience. Ahem. They don't do over 20mm. And the ballistics of their 20/50 are too weak. 
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Posted: 1/26/2021 9:25:47 AM EDT
[#49]
The ability to remotely fire it would be healthy.
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Posted: 1/26/2021 9:42:22 AM EDT
[#50]
Quote HistoryQuoted: Too weak... for what? Quote HistoryQuoted: Quoted: Quoted: Motherfuckers don't even read what I type. https://web.archive.org/web/20150108034204im_/http://www.anzioironworks.com/Photos/Anzio-big-bore-selection1.jpg *ahem* Anzio Ironworks probably has some experience. Ahem. They don't do over 20mm. And the ballistics of their 20/50 are too weak. To closely match the host vehicle's existing targeting systems. |
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