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Thread: Need some help with my M1A

  1. #31
    Indian Admin Winn R's Avatar
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    Quote Originally Posted by Illya Kuryakin View Post
    My oddities are not a result of my education or occupation but rather a direct result of heavy alcohol, narcotic and stimulant use during the 70's and 80's
    Hey Chuck! I went to that school too, but about 10 years earlier. It made no difference though, I still don't remember that decade!

    Quote Originally Posted by wjkuleck View Post
    When economics makes it difficult to do it right as noted above, the "reclamation" procedure is to us a hammer in a strike/stroke fashion around the rear of the barrel, stretching the steel rearward.
    Walt
    I'm missing something, and since I've never done a M14 that's not surprising. I'll assume that at the point it clocks right it also head spaces. So when we torque it in, not only does it not clock right, there's too much barrel at the chamber end sticking in the receiver.

    So why are we stretching the steel rearward at the chamber end?
    There is no nonsense so errant that it cannot be made the creed of the vast majority by adequate governmental action. -- Bertrand Russell


    "Never attribute to malice that which can be adequately explained by stupidity." Robert J. Hanlon

  2. #32
    Gunco Member wjkuleck's Avatar
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    I'll assume that at the point it clocks right it also head spaces
    Alas, that is so not true. One of the ideosyncracies of the M14 platform is that USGI barrels are way long in headspace. 7.62-MM ammunition has the same cartridge headspace dimension as SAAMI .308 Winchester, but USGI mlitary 7.62-MM chambers can be waaay longer than SAAMI .308 No-Go. So, what's a poor commercial M14-type receiver manfacturer to do? Alter the receiver face location so as to acommodate USGI barrels? But, that will allow the bolt to interfere with the rear of the barrel?at least in many cases.

    With a commercial barrel the procedure is this. First, lap in the bolt lugs so that both are bearing evenly and completely. Next, install a short-chambered barrel that will clock at 7:00-7:30 (the position of the web between the feed ramps at the bottom of the chamber) when hand-tight. Torque the barrel to alignment. Finally, finish headspace. This will ensure that the bolt, receiver, and barrel are in the proper longitudinal positional relationships, with "good" headspace.

    (For those who wonder how to final-chamber with the barrel installed, there are pull-through reamers. Even better, in the books below we show how to finish ream for proper headspace with the barrel off the receiver such that when you install, torque & align you have "good" headspace. It's a neat trick.)

    Please consider this: we want the barrel to be in the design position with regard to the receiver, regardless of how we get there. The procedure that has stood the test of time is peening/rolling, as what we're really doing is getting the "crush" back (or creating some if we never had it). We end up with the barrel in the place God & Garand intended.

    When you're starting with a USGI barrel and commercial receiver, UGH! Commercial receivers vary widely in their face positions, even from the same manufacturer over time (S, Inc. is notorious for tool creep). Even the best non-GI receivers currently available, from Norinco/Polytech rifles, have an oddball bolt-barrel relationship. Generally you need to replace the barrel when you replace the bolt (the bolts are not serviceable and must be replaced), because the Norinco/Polytech barrel was dimensioned for the oddbal N/P bolt. If you can manage to fit a USGI bolt with the N/P barrel, you generally end up with short headspace. The N/P barrels are chrome lined, so you aren't going to finish-ream them. Unlike the Garand, you're not dealing with a military standard when you're working with M14-type barrels. We aren't working on our own receiver just for the fun of it. Doing it ourselves is the only way we can get consistenly good recievers on which to build rifles.

    To reiterate, it may just be possible to get away with shimming the barrel. I don't think so. I'm just intent on doing my best to help folks understand the ramifications of going that direction so that they can make informed choices. Believe me, if shimming were the way to go, USGI and civilian armorers would have been doing it for the last fifty years instead of getting out the hammer. Shimming would have been so much easier.

    Regards,

    Walt
    Author, New! The M1911 Complete Owner's Guide
    Author, The M14 Complete Assembly Guide
    Author, The M1 Garand Complete Assembly Guide

    Author, The AR-15 Complete Assembly Guide
    Author, The AR-15 Complete Owner's Guide, Fourth Edition



  3. #33
    Gunco Member wjkuleck's Avatar
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    I think we beat this dead horse all to hell and back
    I agree, and thanks. The question made me really, really think about why we don't shim in the Garand world. It would be so much easier than peening/rolling.

    I'm appreciative of the opportunity to have a respectful give 'n take. It's a bad day when I don't learn something new, after all.

    Warmest regards,

    Walt
    Author, New! The M1911 Complete Owner's Guide
    Author, The M14 Complete Assembly Guide
    Author, The M1 Garand Complete Assembly Guide

    Author, The AR-15 Complete Assembly Guide
    Author, The AR-15 Complete Owner's Guide, Fourth Edition



  4. #34
    GuncoHolic BigAl's Avatar
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    so to peen a barrel, is it just peened around the outside edges of the shoulder or all across the barrel shoulder?

  5. #35
    Gunco Member wjkuleck's Avatar
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    around the outside edges of the shoulder
    The outside edge. You're working on moving the engagement surface rearward. If you have a laghe, you can roll form that edge (Kuhnhausen suggest centering the roller tool on the edge at a five degree angle, to give you an idea of what you're trying to do).

    Regards,

    Walt
    Author, New! The M1911 Complete Owner's Guide
    Author, The M14 Complete Assembly Guide
    Author, The M1 Garand Complete Assembly Guide

    Author, The AR-15 Complete Assembly Guide
    Author, The AR-15 Complete Owner's Guide, Fourth Edition



  6. #36
    Indian Admin Winn R's Avatar
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    Now, I closed my engineering firm several years ago and lost all the smart people, i couldn't figure an integral on a polynomial; and lost the cad folks as is evident.




    ok we need to fill in a gap. Although a very small one. And we can flow the metal off the barrel in or add metal in the form of a shim.

    In either case, the barrel position relative to the receiver does not change.

    I'm not beating anything just trying to understand why one metal is better than another.
    There is no nonsense so errant that it cannot be made the creed of the vast majority by adequate governmental action. -- Bertrand Russell


    "Never attribute to malice that which can be adequately explained by stupidity." Robert J. Hanlon

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