That Made in Canada M203 project...

koldt said:
MikeH said:
Oh - has everyone forgot to mention that an M203 barrel is not round? It has the male portion of a T-slot on it.....forged right in.
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I alluded to it on the first page. 8) Month and a half ago. :lol:
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Is the lug actually part of the forging though? I thought koldt said it looked like it was welded on.
 
KevinB said:
Part of the forging.
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Hmmm. Flies in the ointment.

Well - that's not an insurmountable obstacle.

Here again there are a couple of ready solutions:

1. Look at welding options.

2. Look at composite options. Can the rifled tube be threaded onto a breech that was machined out of a larger piece of stock that has the lug? Similar to the (I think?) 2 pc BHP barrels?

3. Looking at turning the tube out of a piece of stock thick enough to accomodate the lug - expensive.

Or... and this is the best option:

4. Sand or die cast your barrel blanks considerably oversize and then bore and turn them down to slightly oversize. Recycle your aluminum chips for the next casting - very efficient and low over head. Swage the bored and turned blank to size in a steel die on the 450 ton press. The bore die is then removed and the swaging die still containing the barrel blank is inserted into the rifling frame to be button rifled, after which the finished barrel blank is released from the die for deburring/deflashing and finishing. The setup is going to be your biggest expense. Otherwise this is a very efficient procedure in terms of materials useage.

I'm going to have to start charging you for this stuff :D
 
Hi guys,

I've been following this thread off and on for a while now, and the biggest problem seems to be getting the 40mm barrels, and the machining of said barrels seems to be the sticking point now.

I'm going to jump in with a question/idea that might get me beaten with a stupid stick, or maybe not.

Why is it that you cannot simply take a 37mm barrel, and re-bore it out the extra 3mm, then rifle it?

Presto, you'd have your outer rail, you'd have your barrel, and it seems to me that there are lots of 37mm barrels about...or at least enough to spare a few for this project.

If my idea's no good, then I'll just go stand in the corner and let the engineers figure it out, but hey, I'm sure a lot of us would be willing to sacrifice a $400 37mm launcher to get a 40mm one...

NavyShooter
 
NS - I think the best way is to get a 37mm Sleeved M203 barrel from Mr 40mm
and find a way to unsleeve it.

That said as soon as it was proved we could unsleeve them it would get ITAR'd...
 
NS - taking 3 mm out of a barrel that has a wall thickness of ~ 2mm leaves not much left.

SPI, I have been trying to locate a source for the 203 barrel forgings. So far all I have came up with the the actaul reciver forgings, and for what we are planning they will not help us in the reciver end of things.

But i have not spent much time looking right now, the rugrat is taking up a little to much of my time.....oh and the house too.....

Can you belive i dont even have my gun room set up yet?

I degress....

Plan B is to TIG on the T-slot, then do the barrel boring - after a stress relief of course. and then the other barrel treatment.

Casting we feel would not be in our interest at this point, it would be only viable if this turned into a toy only, not a tool. And if that is the case we might as well go 37MM smooth bore. I do not feel comfortable with the higher pressures of HE and non-lethal munitions that some of the customers we are targeting to have access to, in a casting.

A good thought though.
 
MikeH said:
Plan B is to TIG on the T-slot, then do the barrel boring - after a stress relief of course. and then the other barrel treatment.

Casting we feel would not be in our interest at this point, it would be only viable if this turned into a toy only, not a tool. And if that is the case we might as well go 37MM smooth bore. I do not feel comfortable with the higher pressures of HE and non-lethal munitions that some of the customers we are targeting to have access to, in a casting.

A good thought though.
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I rather stongly disagree Mike.

If you proccess the cast blank by die forming as described in my above post and use proper QC testing on it, there is no reason that it should not perform to expectation.

Key to that proccess is good castings, which many companies have issue with, to be sure. But that is easily fixed if you are determined.
 
I guess, to continue with what I mean, is that typically when castings are thought of in industry they are thought of in bare form. In this case, a rough oversize casting, full of porosity, hollows, etc.


But in reality what we are talking about is not so much a casting as a forging. If you will recall from my previous posts, the cast would be considerably oversize, and swaged to finish in a die. So it is in fact a forging and should be considered as such. QC tests on it would need to be arranged with respect to the pressure limits, but there is no reason that it would fail them.
 
On a related note, has anyone seen one of these and can comment? Any more pictures out there?

51c156ab.jpg
 
Ok people,

This whole barrel issue sounds like there is not one single person that can actually machine a barrel or is not setup for doing this.

Riffling is a different story entirely, but it can be done. Ever hear of Bill Holmes? Anyone?
He has a dirty method of doing it: you need another finished barrel as a riffling guide. This results in a slightly damaged initial barrel.

Barrel material does not HAVE to be aluminum.

PM me if there is anyone out there with COMPLETE DETAILLED DRAWINGS of the M203.
Sounds like a neet little project and if it can be LEGALLY made, let's talk.
 
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