Will machine shops build self-designed brass?

D

Dave L.

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I've just started on my new project. This time it's not a wildcat. I'm going to see if I can find someone who will build my cartridge from scratch. The cartridge is unique. If I could I certainly wouldn't mind having the name and calibre stamped onto its head to mark it as my own. I've designed something that I think may just hold water. Details will come later, seeing as nothing has been finalised.

Needless to say I've got a few questions. First of which being legality: is this legal? The brass is just going to be brass, and only brass. I'm not asking them to load and prime it. That I'll do myself.

Secondly, how badly is this going to hit me in the pocketbook?

Thirdly, is this even possible? I mean, assuming I've got the right kinds of designs and all, will they even do it? Or will I have to order an insanely huge amount of the stuff to offset tooling-up costs that'll make this totally impossible for a one-man, *ahem* sorry, one-boy operation?

- Dave.
 
The short answer is no.

The long answer is, not likely.

Brass cases are formed in a set of progressive cupping and drawing dies. There are not likely a lot of shops that are going to have the type of tooling you'd need, and those that do are likely going to ignore you unless you are serious about a few hundred thousand piece order.

In a few cases, desperate reloaders have tried having cases lathe turned from rod, but they tend to be very brittle and short lived. The drawing and repeated annealing of the cases tend to give them far more strength than a case turned from bar stock.
 
Like Canuck223 says, machine shops don't make brass cases. What you can do is find an existing cartridge that has the same size case head and case length and make your brass from it.
RCBS and others will make custom dies for you, but it's horrendously expensive. Give RCBS a call and ask about it.
1.800.533.5000 Monday through Thursday 6:30 AM - 3:00 PM PST
 
So you're looking at a bottle necked cartridge that's a .577 calibre? .577 Tyrannosaur runs $9.20US each from Midway.
You could look at a straight walled case like the .577 Nitro Express(3" long) or .577 3 1/4" and form them. Midway lists them at about $5US each for the Nitro Express. The .577 3 1/4 will be available for as little as $2.05US each if you buy 100. $2.15US each per 20.
I'd be looking into the cost of the dies before I worried about anything else. One 'custom die' site, I looked at, said about $175US per set. You'll need case forming dies too. Just running a straight walled case into a sizing die will likely crush it.
 
It's an ambitious project, not really a .577 calibre, actually .408. The neck-down is going to be at an even 21 degrees. I'm trying to build a scaled-up .220 Swift.

On second thought... the .50BMG may not be such a bad idea after all if I could find a way to slow the taper down a bit. I suppose I could try to blow it out a bit by fireforming the cases if I could build a chamber reamer for it.

I'm guessing this is destined for the pile of all of my failed BMG wildcat ideas... *laughs* Or maybe I'll find a way to get it to neck down successfully. Or not. *sigh* this is mind-boggling.

I'm hoping to achieve over 4000 feet per second out of the muzzle with ~400-gr ammunition without blowing up the whole place, and without having to use a rediculously long barrel. Ambitious project...

- Dave.
 
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Well Dave, you are entertaining, if nothing else.;)

As mentioned above, lathe turned brass if not suitable. It is OK for low pressure black powder loads, but not for smokeless, and definitely not for the over the top stuff you dream of.

You have access to a machine shop, don't you? If so, you can build your own dies and stuff. In the Gunsmithing article I wrote (link below) there is a link to show how to make your own chamber reamers.
EDIT here is the link. http://personal.geeksnet.com/soderstrom/ReamerMaking/HowImakechamberreamers.htm


Stick with 50BMG brass (about a buck or two per case). Dont try to overload it to dangerous levels. BTW, have you done ANY reloading before? Might not be a bad idea to actually learn a bit about standard loads before trying to set world speed records.
 
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Ever seen a 13mm FN, or a 14.5 Soviet? The FN case was experimental, might be hard to find, you should be able to get a 14.5 empty casing for study without much difficulty. High velocity experiments are nothing new, there have been many such projects, research of this sort has gone on for generations. Necking down a large case is one approach, using a sabot with a smaller diameter projectile in a large bore is another.
Why .408"? The only .408 cartridge generally available is the proprietary .408 CheyTac; it is an uncommon bore size.
To actually produce such a cartridge, and create a functional firing device for ballistic testing is going to take many thousands of dollars, and it is unlikely that anything new will be discovered. As mentionned, this sort of work has gone on for years. CGN is probably not a very good place to try to research this information, this is a very specialized field of study.
 
Dave L. said:
I'm hoping to achieve over 4000 feet per second out of the muzzle with ~400-gr ammunition without blowing up the whole place, and without having to use a rediculously long barrel. Ambitious project...

- Dave.
Click to expand...

Instead of spending thousands of dollars and months or years of your time, only to lose an eye the first time you fire it, get a copy of QuickDesign and Quickload and figure out the internal ballistics in advance.
 
Alright, I went to ammoguide and took a look - the BMG case is too short by just about .12" If only I could find a way to lengthen it a little, then I'd probably be in business. The bottom of the body is slightly too thin, by about .105." I don't know if it's possible to get the bottom of the body to open up without compromising the integrity of the brass. :(

Tiraq - I would've gone with a .416" bullet, but the problem was I found it was already done by Ronnie Barrett. I picked the .408 because there were bullets already available for them and they in the EXACT shape and type I want them in - brass/bronze solids, spitzer-pointed boat-tailed. They're out there, I just need to find some. I needed something that would fill the gap between .375" and .416" and .408" was the only thing I could pull up that wasn't obsolete. As for brass... I think the 14.5mm is going to be a little too big. If only I could find one of those old Soviet 12.7x108mm cartridges or any of the 12.7x120mm cartridges, then I'd be in business! :( Thanks for the advice, though, I'll look around for some old 13mm FNs.

Acrashb - That's an excellent idea! :D Do you know where I can get them, though? Order online, maybe?


Tootall - thanks for the link, I'll start on the chamber reamer immediately. I suppose I could use precision ground steel drillrod. I've got a whole stash of the stuff in the back of the store that hasn't been sold off yet and my boss gives me a good discount on most wares. :D

Well Dave, you are entertaining, if nothing else.;)
Click to expand...

Maybe I'm going to set the world record after all... for number of wildcat cartridges that failed! :D

- Dave.
 
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Here's the cartridge specs:

Bullet diameter: 0.408"
Mouth width: 0.4735"
Mouth length: 0.3315"
Shoulder Length: 0.5464"
Shoulder width at mouth: 0.4735"
Shoulder width at body: 0.7322"
shoulder angle: 21.0000 deg
Width at base: 0.8105"
Belt width: N/A
Belt Length: N/A
Rim diameter: 0.8615"
Case overall length: 4.0163"
Cartridge Max Overall Length: (TBA)

They are exactly in proportion to the .220 Swift, only approximately 1.8x larger.

- Dave.
 
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12.7 Soviet is similar to .50 BMG. .50 SLAP (BMG case) used a saboted projectile of about 10mm diameter, resulted in about 4 000fps. An older, WW2 era experiment was the .50/.60. US .60 experimental mg cartridge necked down to .50. It also produced close to 4 000 fps. Application was to be for aircraft.
I think the bullet you are describing is the one for the Taylor .408. Taylor has moved on from the .408, and is working on a .375 version, which has superior ballistics.
.416 has been used for non-proprietary versions of the .408 CheyTac. Taylor's .408 components are about the only game in town in the calibre. Taylor decided to go with a unique case and projectile. The case is based on an earlier design, but the actual draw is different, particularly with respect to casewall thickness in the head and transition area.
There has been lots of work done in this area. The exact cartridge case dimensions are not really critical.
 
troutseeker said:
Sweet Jebus!!! Can I be the first to see you shoot this lightweight sporter???:eek:

Troutseeker
Click to expand...
Sure, I wouldn't mind, so long as I get a chance to train myself up first.


So the exact case dimensions aren't critical, eh? That's good to know. Of course, if these experiments have already been tried I suppose it wouldn't hurt to try something a little hotter and push for more. I'll go get Quickload, this does sound plausible... only problem is getting the brass and sizing it.

- Dave.
 
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I think that Dave's enthusiasm should be encouraged, but Dave..maybe you need to look at stuff that is a little more "practical"

Get your self a Stevens 223 and a case of cheap ammo, and learn to shoot. You have your whole life to design crazy, impractical cartridges...

Join a club and see if they have a youth program, or someone that can help you. I am sure there is a gunnut in your area that will give you a hand!
 
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