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Old January 11, 2018, 03:49 PM   #1
ligonierbill
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Barrel is off the Brazilian

I've not decided what goes on the Brazilian, but I did get the original 8x57 military barrel off. Threads look real good, 12 tpi and the shank is exactly the same length as the original (8x57 reamed to 8mm-06) I replaced on my FN.

I will either send the action to Shaw or buy one of Brownell's short chambered .308 barrels and do it myself. The FN has a Brownell's 6.5x55, and that project went real well. I would go 30-06, but I know from experience that you have to load some bullets shorter than you want unless you want to rework the mag well. I don't. Hate to add yet another caliber, though. Believe it or not, I do not have a .308 now.

Shaw can do most anything, including 9.3x62. It's not on their website, but I called. No problem. It's more money, of course, but they do a real nice job of bluing. On the FN I used Brownell's Oxpho Blue. It worked pretty well, but not as nice as the one I had done by Shaw. If I go to Shaw, I might just stay with 8x57. In any case, I have a winter project.
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Old January 12, 2018, 10:23 AM   #2
F. Guffey
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Threads look real good, 12 tpi and the shank is exactly the same length as the original (8x57 reamed to 8mm-06) I replaced on my FN.
I would have checked the length of the chamber from the shoulder to the bolt face before removing, after removing I would have checked the case head protrusion. And then there is the gap between the receiver face and shoulder at the end of the threads on the barrel. I want the barrel to seat against the 'C' ring first and then seat the front receiver ring against the barrel.

I removed a barrel from a Mauser that had metal cutting between the C ring and barrel face. the rifle had other problems but high pressure metal cutting gas should not have been one of them. When making sure the barrel face contacts the C ring first I use a feeler gage to determine the gap. The front receiver ring will seat after the barrel contacts the C ring when the slack is removed from the threads and then there is a little 'crush' but do not count on the two pieces of metal getting closer together.

And then there is the Chilean 12 threads per inch, I have no fewer than 30 Mauser barrels, When replacing a barrel I am always pleased when the barrel screws into a receiver but there is no guarantee.

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Old January 12, 2018, 01:38 PM   #3
ligonierbill
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See the attached photo of the barrel with a cartridge inserted. I didn't clean this face; the 'C' ring contact area is shiny. So the Brazilian arsenal got it right in '35 at least. When I get the new barrel (.308 short-chambered from Brownell's - backordered) I will verify contact with the 'C' ring before I tighten it completely.

I know there are some odd threads out there. I took the barrel off a Turk that had a short shank and something close to 10 1/2 tpi. This one appears to be standard, but as you say, I'll smile when I see it really fits.

If all goes well to that point, I'll rent a finish reamer and go/no-go gauges and finish the chamber just to the point I can close the bolt on the 'go'. Brownell's says they're short by just 0.01", and my previous experience indicates there is very little cutting to do.

While I'm working this one, I will see how my "new" Pole shoots. If it's a good one, I'm done for awhile. If not, I'll send her to Shaw and let the pros install a new 8x57 barrel. The fun never ends.
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File Type: jpg 8x57 Brazilian.jpg (67.2 KB, 22 views)
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Old January 12, 2018, 03:54 PM   #4
F. Guffey
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If all goes well to that point, I'll rent a finish reamer and go/no-go gauges and finish the chamber just to the point I can close the bolt on the 'go'.
More often than not I finish the chamber before I install the barrel on the receiver; that requires measuring the distance from the C ring to the bolt face and the distance from the receiver front ring to the shoulder at the end of the threads on the barrel and then there is case head protrusion from the barrel.

I would suggest you check the short chamber, I purchased a barrel from Midway that allowed a gage to protrude from the barrel .240", They did not think that was such a big deal even after I explained the .240" is 24 times the amount of ware on the reamer required to finish a chamber that is only .010" short.

F. Guffey

Last edited by F. Guffey; January 12, 2018 at 03:55 PM. Reason: add quote brackets
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Old January 12, 2018, 06:17 PM   #5
std7mag
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I went with a 284 Win barrel from E.R. Shaw. 24", 1.5 contour. Polished, blued. 11 degree recessed crown. Short chambered. $272 shipped to my door.

I put the barrel on then finish reamed.

During break in 5 shot 0.92" with 162gr. Hornady ELDX over starting charge of RL19.

I have nothing but good to say about E.R. Shaw.

I also picked up a 250 Savage barrel for a Savage action. 24" polished, blue. Radius crown on special for $125. Going to put it on my Stevens 200 action.
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Old January 12, 2018, 07:36 PM   #6
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I've spoken with Shilen, and other smiths that have done more Mausers than I, and all agree modern short-chambered barrels don't need to bear on the inner torque ring.
They're of adequate shank diameter to have the needed contact surface area between the barrel shoulder and receiver face- no differently than a Remington, Savage, etc.

Mauser military barrels had such a small diameter very little contact area was present. Some barrels (measured post removal) show they beared only on the inner ring.

While I usually do it "just because", and it doesn't take much extra time it will make no difference in accuracy. The manufacturers of short-chambered barrels obviously intend these barrels to bear only on the outer receiver ring- the DIY market for which these are intended do not have access to lathes to do the necessary machining to bear on both shoulders; if they did they would not need/want a short-chambered barrel to begin with.
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Old January 14, 2018, 11:35 AM   #7
F. Guffey
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I've spoken with Shilen, and other smiths that have done more Mausers than I, and all agree modern short-chambered barrels don't need to bear on the inner torque ring.
And then there are those that claim the Mauser is not a solid platform because they flex, twist and bend. I said I check the length of the chamber before removing the barrel, I said I measure case head protrusion after removing the barrel.

I would choose not to turn this into a; I said, he said, they said thing but a friend, master machinist, former employ of Shilean, maker of gun smiting jigs seats the face of the barrel against the C ring. If the barrel is going to seat against something I want the barrel to seat against the torque 'C' ring. If the barrel is not going to seat against the C ring I want to cut the front receiver ring flat and if you are listening and or paying attention cutting the front receiver ring flat causes the face of the barrel to contact the C ring sooner.

Again, I measure case head protrusion from the barrel. I have at least 30 Mauser barrels, out of the 30 at least 25 of them have .110 case head protrusion, If I had to guess I would guess if I installed the barrel on a Mauser receiver I would have .005" clearance. If I choose to reduce clearance I could remove metal from the face of the barrel, but IO would not want to forget about the front receiver ring.

I have custom barrels that were removed from Musers that were built in custom shops, one of the barrels had .140" case head protrusion, the barrel was not seated against the torque ring.

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Old January 14, 2018, 11:44 AM   #8
F. Guffey
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I have two heavy barrel blanks/unthreaded, my intent was to install on P14 and or M1917 receivers, I am hesitant to install the heavy barrels on Mauser receivers because if I take what he said they said about the floppy receivers seriously the barrel could droop.

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Old January 15, 2018, 09:15 AM   #9
tobnpr
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Mr. Guffey,
It's not a "he said, she said".
Professionals, will often turn the shoulder so that the inner ring will be contacted when the barrel is torqued into place. I've never seen any evidence that a modern barrel with full contact only on the front receiver ring is any less accurate than if it contacts both.

I was referring to installation of pre-fits- which are designed to be installed DIY for those without access to lathes.

You have your opinion, I have mine. I'll agree, to disagree.
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Old January 15, 2018, 11:04 AM   #10
F. Guffey
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Quote:
It's not a "he said, she said".
Professionals, will often turn the shoulder so that the inner ring will be contacted when the barrel is torqued into place. I've never seen any evidence that a modern barrel with full contact only on the front receiver ring is any less accurate than if it contacts both.
We had a member that said they said and I wondered if they ever measured case head protrusion. He went on to say they said .175" case head protrusion was OK and acceptable to SAAMI. And I said I have never found an 03 or 03A3 with more than .090" case head protrusion when measuring from the bottom pf the extractor cut. I do not know of a reloader that measure case head thickness from the top of the cup above the web to the case head. I would not want to fire a case with .175" case head protrusion with a case head that was .200"; because there is such a thing as unsupported case head.

I would suggest the reloader find some thick headed cases for .175" case head protrusion. I have found 30/06 cases with .260" thick case heads, my opinion the thick cases head is safer. And then there are all of those claims about soft case heads.

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