Why would a gunsmith change the shoulder of a 338 Lapua ?

Discussion in 'Reloading' started by texasdave, Jun 9, 2009.

  1. texasdave

    texasdave Well-Known Member

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    I have a 30-338 Lapua that the smith that built it changed the shoulder to a 38 degree angle on the case. My reason for asking this question is that forces me to fire form all the brass. I have the formula which is 19 g of unique and a 150 g molly bullet. With the shortage of supplies now days I have been looking for a way around fire forming and so far have not found it. My search then brought the question to my mind why was the shoulder changed? Do I really get anything more by doing that? I know I can not change this until the barrel needs to be replaced and I have not seem to have a capacity problem but I am sure there is a good explanation and I was hoping someone could explain it to me. I appreciate your time.

    Thanks,
     
  2. britz

    britz Well-Known Member

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    Are you sure that the case isn't blown out too... that it is actually a 30-338 lapua improved??? To my knowledge that would be the most reasonable explination.
     

  3. CapDog

    CapDog Well-Known Member

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    I've never worked with the 30-338 version but on the straight .338 Lapua Improved the gunsmith I deal with is driving 300gr Sierras to the 3000fps mark and higher. Plus he is finding that with the improved version he doesn't have to trim his brass even after numerous firings. My 260AI is the same, no need to trim the case length.

    Check with Hornady I thinky they make a hydraulic die that will allow you to form brass. I'm sure someone on here can confirm this or not.
     
  4. cinch

    cinch Well-Known Member

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    Maybe so it can not be accidently chambered in a standard 338 Lapua?
     
  5. texasdave

    texasdave Well-Known Member

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    Guess I need to measure to be sure about the case being blown out too. Interesting. I do know he was taking the regular 338 Lapua case and then necking it down and then fire forming it. This is great info to look at. The more I think about it the case shoulder is up making the body of the case longer. I will have to measure tomorrow.
    Thanks
     
  6. Ridge Runner

    Ridge Runner Well-Known Member

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    min. body taper and sharp shoulders make trimming cases almost unheard of. you shoot higher pressure with less pressure signs so you get higher velocity.
    You can fireform without bullets, just charge with 19-20 gr of unique, fill the case with corn meal, tap the case to settle the meal, then plug it with a rolled up "worm" of paper towel, press it in tight with a punch or small allen wrench.
    I form cases like this all the time, but I do vary the charge depending on case capacity.

    However, do not discount the accuracy potential of fireform loads, when I used moderate loads to fireform 338 LM cases to 7mm Allen mag, my fireform loads would shoot in the .2's
    here is a target
    [​IMG]
    RR
     
    Last edited: Jun 9, 2009
  7. J E Custom

    J E Custom Well-Known Member

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    Dave.

    Did you buy it that way or did the smith change it without you permission.

    If you bought it like that It should have been marked on the barrel that it was a 300 Lapua
    38o. Any chamber that is not standard should be marked on the barrel ID.

    The standard shoulder is 25o 67' so it has been blown out and top pressure loads should not
    be fired in it.

    If he chambered it with the 38o shoulder and did not check with you first then I would ask him
    to set the barrel back and chamber it with the standard 300 Lapua mag reamer if you don't
    want to fire form the brass.

    The 38o shoulder will give you a little more powder capacity and may improve brass life but you will have to reform your brass one way or the other.

    I have to assume that he made you aware of the difference and the brass requirements.

    J E CUSTOM
     
  8. BountyHunter

    BountyHunter Writers Guild

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    Hornady has announced a "hydrylic forming die" that can be ordered from them. It uses water in the case, a matching form die and a dead blow hammer to drive a piston down in the case and form to the chamber.

    Contact Hornady Technical Dept, Lonnie Hummer.

    I sure would not use a moly bullet to fireform if you are not using moly bullets regularily. Moly is super hard to get out of the bore and copper will form on top of it.

    BH
     
  9. texasdave

    texasdave Well-Known Member

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    I did talk with the smith about the changes. I was aware but now that I am working new brass I have become aware of the differences. I would not blame him at all. I also agree on the molly bullets. I did not like that Idea as I do not shoot them and had heard of the build up before. I like the fire forming Idea of using cornmeal as my other concern was barrel wear. I am not sure about max pressure but so far that has not been a problem. I am not shooting 300g bullets either. Most of my loads are on 180g to 200g bullets. My other concern was if I needed to replace the barrel I would not have his reamer available or hims so I wanted to not end up with lots of brass etc and then have to start over with a new chamber etc.
    I like the Idea of Hornandy's new dies and want to check on that.

    I really appreciate everyones suggestions and can not begin to thank everyone for their help !!
    Sincerely,
     
  10. jmden

    jmden Well-Known Member

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    I guess I don't understand the concern.

    You have one of the best .308 chamberings money can buy. I would say the best for a packalbe rifle. The 338 Lap case is one of the most consistent and strongest cases (if not the most) on the market. You have a 30-338 Lapua Magnum Improved (30-338 Lap Imp). Blowing out the body and sharpening the shoulder does a number of things for you, some already mentioned, but increasing case capacity is not the least of these. This will allow higher velocities than the standard case and with the improved configuration, you will have better case life as well.

    One Canadian smith tha frequents here and has made many rifles from this improved case, has well over 15 firings on his 338 Lapua cases (pushing a .338 300g SMK at 3050-3090fps from 30" barrels) and he reports the cases are still going strong--increased performance and better case life. That's why people do what your smith has done to your rifle. More ummpphh and better case life. I'm doing the same thing, but in .338 for the same reasons. Many, many other smiths build on these cases as well. You can't go wrong using this case.

    That case is probably the strongest case on the market for use in sporting rifles. It was initially rated at nearly 70000 psi and was initially designed in the 80's from the ground up as a sniper cartridge designed for use out to 1500 meters. It was and is designed to take more pressure than any other case on the market than I'm aware of.

    To really take true long range advantage of that chambering (600-700yds or more), you should consider shooting either the 210g Berger or the 240g SMK. I shoot a 240g SMK under 104g US 869 in a 26" 300RUM (cold temp load) with 215M primer and have an average MV just under 3K fps. You should easily be able get another 100fps over that and probably be looking at about 3250fps or perhaps more with the 210 Berger. What is your current barrel length and load. Many on this site agree that a 180g bullet is a waste in the 300RUM and this would be even more the case in your larger capacity, stronger case. 200g at a minimum and look at the 210 Berger and 240 SMK.

    You've got a great thing going. Many on this site and elsewhere would be very happy to have what you have. A little fireforming is a minor inconvience next to the many more firings you should get out of the very stout 338 Lap case vs. other brass. Use the cornmeal/toilet paper method to preserve barrel life if you want. It may be that your smith has a barrel chambered in this round just for fireforming. If so, he may charge you a small amount to fireform for you. I just sent 100 .338 Lap cases to Fiftydriver to have this done--one less thing I have to do and it saves barrel life. You might check with your smith.

    Your smith got the reamer from a reamer supplier. Ask your smith who make the reamer. Whether or not it's your smith's proprietary design is another question you should ask you smith. Regardless, the reamer manufacturer will have the reamer specs if you want to buy the reamer to rebarrel, but I would think your smith would let you use his and why not have him chamber it again if the need arises anyway? You'll not want to chamber to a different dimension reamer anyway as then your dies won't work. You've got a great setup. Fireform and then enjoy!
     
  11. trueblue

    trueblue Well-Known Member

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    texasdave,
    +1 on jmden's post
    In your rig I would be shooting 210 Berger's or 240gr SMK.
    Also, did your smith make you custom dies, or did his reamer match up with industry standard dies ?
     
  12. texasdave

    texasdave Well-Known Member

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    I agree with this last two postings. I guess I have not explained, the smith I used is no longer in the business. It is a very unfortunate situation but that option is not available. I went to him and have always respected his vision and especially his work. Due to no differences between us in any way he is unable to help.
    I wanted to find out why he had done what he did. I think everyone has answered this for me and the information that has been shared here really has helped. For one the subject of bullet weight was never explained to me like here. On his load development he never shot heaver bullets and I will say that I shoot at another smiths range and he has never suggested a heaver bullet. In defense of him he mainly works bench rest rifles. To me it just goes to show ask people that know and you will find the answer.
    I really appreciate the help. Oh to answer the question about dies yes he built custom dies. I also think he had a rig with an older barrel he fire formed the rounds in. I would still go that way but unfortunately that is not an option. I can not say enough thanks for all the kind help and advice. Hey I hope I can repay the favor along the way.
    Sincerely,
     
  13. jmden

    jmden Well-Known Member

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    Is there any way that you could find out if the reamer he used is available for purchase? Or, could you find out which reamer manufacturer made the reamer and order another from them if and when you want to rebarrel? Some guys will rebarrel a second cheaper rifle just for fireforming to save their nice premium barrel.

    The bullet weight thing is more about ballistic coefficient of the bullet. The higher weight bullets in the same caliber will be longer and necessarily have a higher bc. In long range shooting, bc is king. Higher bc bullets will have less wind drift and slip through the air with less resistance, holding on to their killing energy out further for more (hopefully) ethical kills than shorter, lower bc bullets. 180g Nosler Accubond--.507bc, 200g Accubond--.588bc, 210g Berger--.616bc, 240g Sierra Matchking (SMK)--.711bc. The 240 just slips through the air easier and retains more energy downrange with the appropriate slow burning powder.

    Good luck!
     
  14. texasdave

    texasdave Well-Known Member

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    JmDen;
    You have some great info and I will try and contact the smith but I am not sure if he has any of his equipment still. That is a great thought though. Thanks for the info on the bullets it makes this all come together better for me. I will tomorrow do some checking and measuring etc. I was at the range today all day and just got in.

    I do appreciate all the help guys!
    Sincerely,