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Old July 24, 2013, 05:16 PM   #1
LOUD
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installing new barrel on a mauser receiver

I am installing a new barrel on a mauser receiver. The receiver is a model 98 by JP Sauer and sons, it is a new barrel from Midway USA (Adams and Bennet). I watched the videos by Larry Potterfield , they all show him screwing the barrel on by hand all the way till the barrel touches the receiver. that's not happening here , I turn the barrel maybe 3/4 turn and then it gets tight, of course Im Just using my hands and no tools yet . How much force does it normally take to screw them together? the threads in the receiver look fine as do the threads on the barrel , everything looks in square but its tight before a complete turn . Any advice would be greatly appreciated................LOUD
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Old July 24, 2013, 06:44 PM   #2
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We put the barrel in a barrel vise and then use an action wrench to install the receiver. We "slam" the wrench three times, that is, when there is about 1/2 rotation left, we throw the wrench as hard as we can. Think of it as an old airplane that needs to have the propellor thrown. Same thing. After the third time, the barrel and recevier are as tight as it is going to get. We then check the barrel with a "go" gauge and then a "no go" gauge.
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Old July 24, 2013, 07:00 PM   #3
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I appreciate your reply , I read somewhere that mausers have a 55 degree thread angle and that new barrel manufacturers make barrels with a 60 degree angle for ease of manufacture . what is up with that? If you cant make it fit exact ........don't make it!!!! anyway it aint budging. any suggestions?........................LOUD
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Old July 24, 2013, 07:15 PM   #4
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If it is a different thread angle, then one would have to be recut, and hope there is enough metal to not kill it. First, measure the OD of the barrel threads, and see if they may have gotten it too fat. You may be able to take off a couple of thousandths from the thread tops, and it loosen up. As long as it comes to about 75-80% thread contact, you'll be okay. You may want to use a thread gauge to see what the thread actually is, since all fish tails are 60 Deg., and check the TPI. Checking the internal thread would have to be done with a boring bar, etc, with a 60 Deg. tooth on it, and see if it fits the thread.
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Old July 25, 2013, 04:07 PM   #5
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They don't always screw in by hand like on the video, but those usually go with a barrel vise & action wrench.
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Old July 25, 2013, 04:37 PM   #6
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In 2009 I got off a forum a pre threaded pre chambered pre blued Douglas 260 Mauser barrel.

I have dozens of 98 Mauser receivers lying around waiting for barrels.
Only one receiver would accept the barrel, a VZ24 with markings different from my other VZ24s. It came with a welded and engraved bolt handle. Someone on the internet sent it to me, and I do not know much about it.

I could have put the barrel in the lathe and synchronized cutting threads to the existing threads. Then I could have cut down the threads enough to fit on any of the 98 Mausers.

But I got lazy and put on the one that already fit.


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Old July 25, 2013, 09:18 PM   #7
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guys I really appreciate your replies, I have it bound between the wooden jaws of a barrel vise and have coaxed it all on except maybe an eighth of an inch to go. now the barrel wants to spin . any of you sages of wisdom got any tips or helpful ideas ? Thanks........................LOUD
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Old July 26, 2013, 02:32 AM   #8
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Yes: Don't force it.

If the threads are too tight, use a dovetail file on them. Or lapping compound.
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Old July 26, 2013, 07:34 AM   #9
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Still going with screw on by hand?
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Old July 26, 2013, 12:53 PM   #10
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I hope you used anti-seize on the threads.

I guess you know that on a 98 Mauser, the main contact point is not the shoulder but the inner collar. The barrel should be set up to contact at both the collar and the shoulder at the same time.

If the barrel turns in the barrel vise, it may be because the barrel is as tight as it can get, or because the vise is not tight enough. While some folks suggest using wood for the bushing, it simply doesn't work when a barrel being removed is too tight or one being installed needs extra tightening. The wood will crush before it holds tightly enough.

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Old July 26, 2013, 01:00 PM   #11
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Barrel shank length = (Distance from Inner Collar to Receiver face) - .002" (for crush depth).
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Old July 26, 2013, 02:20 PM   #12
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If you have slipping on wood barrel jaws, obtain some rosin. Generally you can find a bag at a sporting goods selling baseball and golf equipment. A little dusting, and it will greatly increase the grip power. I have a bag I use all the time, and before each use of the vise.
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Old July 26, 2013, 02:21 PM   #13
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Quote:
Barrel shank length = (Distance from Inner Collar to Receiver face) - .002" (for crush depth).
The same way I calculate it too.
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Old July 26, 2013, 09:06 PM   #14
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FWIW, I always used bronze barrel vise bushings and never had a problem. I did try wood once, but wood can/will crush before it is tight enough for a stubborn barrel.

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Old July 26, 2013, 09:14 PM   #15
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I recently dealt with this too... had to take a thread file and dress the threads a bit. fit snug as a bug after a little work
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Old July 26, 2013, 10:12 PM   #16
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well now Im making a set of wooden jaws for thevise that grip the barrel for about 5" inches instead of 1.5" hopefully this amount of contact will hold the barrel and I can seat the barrel against the inner torque shoulder . ..........................LOUD
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Old July 26, 2013, 10:31 PM   #17
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James,

What wood did you try? I use 8/4 rough sawn white oak, preferably, but red if I need to, and a thick block of it. I would say beech would be even better, though I've not tried it. Of course, you could probably use a bronze split busing with wood too, if there was a way to bond it to it, without it breaking loose.

I don't sand the hole smooth after I get it made, leaving it rough bored, then apply the rosin. Once you un-clamp it, though, the bore is pretty much mashed flat and smooth.
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Old July 27, 2013, 08:17 PM   #18
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I used oak a few times when I didn't have the right size bushing, I don't now recall what kind. But there was always enough compression to keep the barrel from being clamped really tight. IIRC the wood worked OK if the barrel was not too tight, but if it was, the wood wasn't good enough. Sure, I could have made a relief cut (and often did if the barrel was scrap) but couldn't do that when the barrel was to be reused.

I guess I just don't know why there seems to be such opposition to using metal bushings; if used right they won't scratch or score the barrel.

FWIW, I see now that Brownell's has only steel or aluminum bushings, but we had bronze (Babbitt metal?) bushings, which worked just fine.

Jim
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Old July 27, 2013, 10:40 PM   #19
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thanks guys for you input , I finally reached the end!! It took 3 evenings of tightening and gaining ground and then the barrel spinning in the blocks. finally when I made blocks of fresh cut white oak 3 1/2 x6 . after experimenting with the 6 " dimension I seemed to have enough contact with the barrel to hold. Now on to hand reaming the chamber and head spacing. Im looking for good advice on that too , this is my first custom gun. Thanks to all....................LOUD
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Old July 27, 2013, 10:56 PM   #20
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I chambered my barrels with the receiver off.

I put the stripped bolt into the receiver and measured at four different places (12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock) the distance of the bolt face to the receiver face. I then used the largest number. This is subtracted from the shank length (let's call it headspace distance).

When I put in the headspace gauge into the barrel, I measured the distance of the end of the shank to the backside of the headspace gauge. I then used the finishing reamer until the the distance of the headspace gauge protruding from the barrel equalled the headspace distance discussed in paragraph #2.

Afterward the barrel is installed into the receiver and the bolt inserted with a go gauge. If it closes easily, then it is tried again with the no go gauge. If it doesn't close, you're good to go!
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Old July 27, 2013, 11:01 PM   #21
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Jim,

Babbitt is an alloy (white metal) with a low melting point similar to or lower than solder. It has several different formulas, according to who made it, but the trick of it is, casting it around the barrel to get an exact taper to grip it with. I think Brownell's sells it too, or they used to, in bars. You can easily melt it in a lead pot, then pour it into a mold. It was designed to be poured into molds with pillow blocks to form bearings for line shafting. It's really good for split bushings in barrel vises.

On the wooden blocks, you just need them big enough, and with enough surface area to not slip, and adding rosin helps this. I drill them to a size for the smallest diameter of the barrel I want to grip, then taper them with a sanding drum, or a, adjustable taper reamer, which leaves a coarse cut behind. Once done, I split them in two with a band saw.
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Old July 28, 2013, 01:22 PM   #22
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Quote:
Quote:
Barrel shank length = (Distance from Inner Collar to Receiver face) - .002" (for crush depth).

The same way I calculate it too.
If the shank length is shorter than collar-to-face distance, the shoulder would contact the receiver face first and shoulder would be the main contact point instead of inner collar. Should it be +0.002" instead of -0.002" if sitting on Inner Collar is more desirable.

For Mauser's 12 TPI thread, barrel turns 360 degrees per 1/12" advance, or 360x12 degrees per inch advance of thread.

0.002" = 0.002X360x12=8.64 degrees turn from hand tight (barrel touches inner collar). Does not take much torque to apply 8.64 degrees, I guess maybe no more than 40 ft-lbs. So, the shoulder will be pressed hard against receiver face as well when a typical 80 ft-lb is applied to install a barrel.
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Old August 1, 2013, 12:11 PM   #23
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We apply dykem on two places of the shank. First would be on the breech end of the barrel shank that contacts the C ring/collar. The second is at the shoulder where barrel will contact the breech face. When we slam our barrels on and then pull them off, we check those spots. If the dykem is removed, that ensures us of contact at both points. The barrel is then reinstalled and slammed on again (you can tell by the action wrench if it's at the same point).
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