Discussion in 'Technical Articles - Discussion' started by ADMIN, Mar 10, 2009.

Group Therapy - The Problem: How Accurate Is Your Rifle?

  1. ADMIN

    ADMIN Administrator

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  2. Buffalobob

    Buffalobob Writers Guild

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    In Figure 4 is difficult to figure out what the units are for the horizontal axis. Without knowing that it is difficult to do anything but take you word for what the analysis actually proves.

    Secondly, I was reviewing the results of the recent Cactus benchrest match and it appears that there is exactly the data available for you to determine if your hypothetical calculation actually transfers into the real world where data is not generated by random numbers but is actually determined by factors such as how well the recoil lug is bedded and what direction the wind is blowing from. You could take five shooters from the top and five from the middle and five from close to the bottom and see if their groups size is normally distributed which I suspect it is not and further I suspect that the kurtosis is greatly different and that there will be positive skewness.


    It is an interesting article but Figure 4 just lost me.
     

  3. cva54

    cva54 Well-Known Member

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    You mensioned how well the recoil lug was bedded. How tight do you like it? Right now on mine you have to wiggle the action ALL the way down.
     
  4. Buffalobob

    Buffalobob Writers Guild

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    If you wish to start a fight go post that question under Gunsmithing. It doesn't matter what I like, the gunsmith will bed it however he likes and then if he sees one of my bedding jobs he will ask why I messed the gun up and do I wish for him to fix it. :D

    About once very six months I go see Eddie Harren to have him fix one of my rifles. He just looks at me like I should not be allowed to own a gun because it is always the same problem. I am sloppy and spill solvent while cleaning and it just runs every where and gets into every thing and causes all manner of grief. Eddie always fixes it and then gives me a lecture and I always promise to be neater. :D That reminds me, I need to order another 55 gallon drum of solvent.
     
  5. cva54

    cva54 Well-Known Member

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    no not trying to start a fight. But I see persenal pref.
     
  6. Buffalobob

    Buffalobob Writers Guild

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    Well, we might as well hijack this thread being as it does not appear the owner is going to come and answer my question.

    There are two ways of bedding a rifle and for the average hunter either way works if done properly.

    First is the way you and I learned to do it which is to bed the recoil lug in as tight as possible on all sides so you can just barely get it back out.

    Second way is to apply a layer of tape to the left and right side of the recoil lug and one or two layers to the front of the recoil lug and then bed the lug. Once the goo has cured you take the action out and take off the tape and put the action back in. This leaves the recoil lug in contact at the bottom and at the back and no contact on the sides and front.

    I do not understand why a rifle will be accurate with freedom of the recoil lug to move right and left but I have one bedded that way and it is fine. And lots and lots of gunsmith use that method to build really accurate rifles so the fact that I do not understand just means that it is a good thing I am not a gunsmith. In my opinion it is best to let a gunsmith build a rifle the way they are comfortable doing and to choose one that knows how to build what you want built.
     
  7. denton

    denton New Member

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    The image switcher virus somehow modified Figure 4. Here is the correct one. It should make more sense now.

    [​IMG]
     
  8. Buffalobob

    Buffalobob Writers Guild

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    Thanks, that helps a lot. In case I didn't make it clear, I really enjoyed the article.
     
  9. KIWI AL

    KIWI AL Active Member

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    great read and very well explanied.
    maybe the random poor groups are not my doing after all:D
     
  10. McMillan

    McMillan <strong>Official Sponsor of LRH</strong>

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    This is in response to bedding a recoil lug. I can't imagine that there has been anyone that has bedded more stocks than the guy who has been bedding stocks for me for almost 25 years, and for my father before that. He averages five a week. Of course what we do is a little more than a "bedding job", we refer to it as a complete installation. In any case, he learned my fathers technique. And I agree with Bob to an extent, technique is a personal preference unless there is emperical data that supports one method more than another.

    We only bed the recoil surface of the lug. We tape the sides, bottom and non-recoil face. On most cylindrical receiver the lug is technically not part of the receiver. It's only function is to keep the receiver from moving rearward. Therefore the only critical face is the recoil surface. With a Sako, Howa, Weatherby and others where the front guard screw screws into thew recoil lug we bed the bottom because that is the surface that bears the force of the guard screw. A flat bottom receiver like a Model 70 where the screw does not screw into the lug we don't bed the bottom.

    Our theory is that bedding is designed to create a stress free union between the stock and the receiver. The fewer surfaces you have to bed, the more likely you will achieve your goal. It's our contention that how you actually apply the bedding process has a lot to do with whether you are successful or not more so than the area you apply the bedding compound.

    Just a side note, my father was the first to "glue" an action in back in the day when they sleeved Remington actions too.
     
  11. McMillan

    McMillan <strong>Official Sponsor of LRH</strong>

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    Ok, lets take this one step farther.

    Pillar bedding: Pillars are used specifically to prevent compression of the action area material when tightening the actions screws.

    Putting pillars in stocks started back in the early 70's. In the beginning McMillan made fiberglass stocks specifically for benchrest. After about 2-3 years we started to transition into the hunting stock world. Our first hunting stocks were actually our M40A1 stock that we designed for the Marine Corp. Since it resembled a heavy barrel hunting rifle stock we started putting just about every rifle imaginable into it, thus the name General Purpose Hunting stock. The stocks we made for the Marine Corp were 3 pounds so to make a hunting rifle stock we needed to lighten it up. Our first hunting stock had glass beads and epoxy in the action area. As a result you could compress the material by torquing the guard screws. My father started to drill out the guard screw holes to 3/8th's, wax the screws real well and let the hole fill up with bedding material. Then after the screws were removed from the cured bedding he would drill out the hole just large enough to clear the screw screw. That was the first pillar. Since the bedding material was hard and dense, no more compression. From this original pillar the move to aluminum pillars followed several years later.

    As time passed and we got more knowledgeable about available materials and how to use them we went away from a glass bead only material to a combination of fiberglass and beads. The denser material meant that there was less likelihood of compressing the material when tightening down the action screws. Today, you don't need to use pillars in our stocks. The material is dense enough that there is no compression when tightening the action screws. So you ask why do we still use them, right? Because it's "state of the art". Because we started using pillars and everyone adopted this method as the "proper way to bed a rifle" we have continued using the process even though it is not necessary.

    One last thing, we have made thousands of rifles over the years and have never used a torque wrench to tighten the action screws. We sold some packages to the military that included torque wrenches but it was because they asked for them, not because we use them. The key to torquing action screws isn't how much, but how consistent you are. My fathers technique was snug, then a quarter turn. Try that and then put a torque wrench on it and I bet you are real close to 45 in/lbs. Regardless of what Remington or anyone else says you don't need anymore than that. Just make sure that both screws are equal. If you want to use a torque wrench set it at 45. If you are using pillars and your action area material is dense, tightening will just stretch the screws. At 65 in/lbs you can twist the head off a standard Remington action screw.
     
  12. Boss Hoss

    Boss Hoss Well-Known Member

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    Edited
     
    Last edited: Nov 7, 2011
  13. McMillan

    McMillan <strong>Official Sponsor of LRH</strong>

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    I don't think it really matters what type of aluminum you use. In our molded in pillars we use aluminum tubing with .045 wall thickness. In our bedded stocks we use a 1/2" round stock drilled out to 5/16ths. If you could stand on the molded in pillar upright and distribute your weight evenly you could not crush it. Being a cylinder it has more than enough strength to do the job.

    Some people radius the top of the pillar to match that of the receiver. We don't, we leave the top flat and let the bedding material (Marine Tex in our case) cover the top and create the radius. We do this much for the same reason we bed the recoil lug the way we do, because that is the way Gale did it. Theoretically it reduces the chance of creating stress in the union between the receiver and the pillar.
     
  14. McMillan

    McMillan <strong>Official Sponsor of LRH</strong>

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    Boss, there might be a fist fight between the two over who knew more about gunsmithing, my father Gale or his brother Pat. Unfortunately both have passed away. Truth be known they shared almost everything they knew with each other, but Gale built many more guns than Pat did. Pat spent most of his career making barrels. He was renowned as the best barrel maker of his time but due to a bad heart sold his business to Bill Wiseman in 1984. Bill still operates McMillan Rifle Barrels, but somehow it's just not the same. Gale made his own barrels when he started G. McMillan and Co in 1984. In 1987 he got an offer too good to refuse and sold the company, worked out his three year contract and retired from the gun business. In 1992 he started McMillan Vision Master Scopes. He actually designed and produced the first day/night vision scope by using a light intensifier tube that screwed on in place of the rear lens housing. You could actually change from a regular scope to a night vision scope in the field by unscrewing the rear lens housing and screwing on the LIT housing. He sold that business to Seiler Optics in 1997 I think it was.

    We buy triggers and barrels. Because we build 350 to 400 rifles a year, and don't want to be in the retail trigger or barrel business, we figured we could buy the very best of each for many years before we could recoup the investment it would take to tool up to make our own. I honestly believe, even considering our reputation for excellence we could not make any better triggers or barrels than the ones we put on our rifles. We buy Schneider (who learned to make barrels from my uncle) and Lilja. The reason we use both is to insure we have a constant supple regardless of how busy either of them gets. We buy all of the triggers used on our hunting rifles from Jewel.