Rechambering a Stellite-Lined Barrel


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barnbwt
December 10, 2012, 09:12 PM
I've been trying to track down a barrel for my Steyr M95 rechambering project. I scored a used set of 50 Alaskan dies for 20$ (:D) so I've taken that as a divine signal of which caliber to go with (I had been leaning toward 45-70). I'd like to keep the price as low as possible, so the high-end Krieger and Lilja match barrels are out (this is for a short-range thumper/express rifle, after all). The rate of twist for purpose-built 50AKs (from custom shops) seem to be around 1:20, the original 50AK used a 50cal MG barrel. As best as I can tell, such a gun was likely an M2 or M3 which look to have a twist of 1:15 (i.e. even more stable).

It seems that milsurp barrels are the only <500$ game in town, unless someone knows of a Green Mountain-type "budget" maker that does .510 bores. The M2 and M3 barrels on Gunbroker seem to be going for ~300$, and I also learned that the Soviets apparently had their own fifty; the 12.7x110mm (which also has a 1:15" twist. Coincidence?;)). There is only one 12.7mm Barrel on GB, a monstrous AA tank barrel that's 40" long and 3.5" in diameter at both ends (flash hider)
http://pics.gunbroker.com/GB/320817000/320817678/pix844083863.jpg
I'd prefer something that I wouldn't have to pay for a ton of turning on, so this guy's probably out (cool as that brake may be). A 40" "heavy" barrel would probably tame the recoil a tad, and even scare Mad Max, too:D

Which brings me (finally) to my question; all these machine gun barrels are Stellite lined, which we all know is a super hard, super tough alloy. I assume the barrels can be cut just as easily, but can they be reamed? Or will they require carbide or multiple HSS reamers? If tooling would cost an extra couple hundred bucks, the "civilian" barrels would obviously be more appealing.

Again, if anybody knows of a source for 50cal or 12.7mm MG barrels, please let me know. It would be fantastic to keep the price under 300$ (since the rifle only cost 100$, after all)

TCB

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Edarnold
December 10, 2012, 10:11 PM
No way are you going to recut a chrome lined barrel. Unless you are planning to shoot 700gr bullets in your .50 AK, a 1 in 20" twist should be plenty fast enough, faster is just going increase your chances of instability with shorter bullets. With all the .50 caliber muzzle-loader rifles being built, there should be some maker with an appropriate twist barrel in production, which would be a cheaper starting point. Also contact Badger Barrels in Wisconsin, they make all kinds of calibers and I don't think they are too expensive.

IMHO

Shadow 7D
December 10, 2012, 10:27 PM
Yeah, I'd go with what he said
otherwise you are looking at having to grind through the layer to rebore and that's still going to chew your reamer.

PRD1
December 10, 2012, 10:27 PM
in machinegun barrels is only the length of the chamber and a few inches of the bore - you could cut off the entire rear portion of a typical MG barrel and eliminate the lined portion, with enough length left to make a rifle barrel. You can't ream the stellite portion with any tooling you are likely to want to pay for.
On the other hand, I don't think you've exhausted your possible sources for commercial cal. .50 barrels, which would be much cheaper and more satisfactory in the long run.
PRD1 - mhb - Mike

barnbwt
December 10, 2012, 10:30 PM
Is Stellite the same as chrome lined? Wiki says it's a "chromium alloy" but I don't know if that means the same thing as in my VZ58.

With all the .50 caliber muzzle-loader rifles being built, there should be some maker with an appropriate twist barrel in production
I thought so, too. But the only ML barrels I saw had round-ball-type twists in the 30's and beyond :(

I'd prefer a 1:20" since it really is all that's needed, but 1:15" seems to be all the milsurp barrels are rifled to. I didn't know you could "overspin" a bullet; I always assumed more is better, until the rifling starts chewing up the bullet and its centripetal acceleration rips it apart. Is there a calculator for the "low end" allowable weight for bullet stability (Greenhill's is for max length, IIRC)?

On the other hand, I don't think you've exhausted your possible sources for commercial cal. .50 barrels, which would be much cheaper and more satisfactory in the long run.

What an eerie coink-ee-dink!

EDIT:
This may be a moot point; I appear to have just found a barrel blank for ~100$--hopefully this pans out :cool:. At that price, it could be 1:1" twist, and I'd give it a whirl :D. Good to know that even a thin layer of Stellite will trash a reamer; won't have to learn that one the hard way, now.

TCB

Jim Watson
December 11, 2012, 12:12 AM
Stellite is a chromium alloy, very very hard. It is a separate piece inserted into the chamber and throat area of an MG barrel. There are armorers manuals describing how to use wrenches to twist the inserts out of worn barrels. Stellite is Expen$ive and worth the effort to recover.

It is not the same as a thin chromium PLATING that can be cut through with carbide tooling.

rcmodel
December 11, 2012, 10:51 AM
+1

Stellite is not a plating, its an alloy.
And it is harder & tougher then woodpecker lips.
You won't touch it with any common barrel tooling.

Back on the farm, my dad used to have his plow shears rebuilt & hard faced with it by a welder so they never wore out again, ever.

rc

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