338 Lapua reamer question

Discussion in 'Gunsmithing' started by eitmsmf, Jun 5, 2007.

  1. eitmsmf

    eitmsmf New Member

    Messages:
    2
    Joined:
    Mar 17, 2007
    I'm trying to decide on the neck size. I don't have a loaded round to measure nor am I sure on how much clearance I should have. Gun will be set up for 300gr MKs. Thanks in advance for any help.
     
  2. James Jones

    James Jones Well-Known Member

    Messages:
    2,854
    Joined:
    Jul 1, 2002
    I have a loaded round diagram that another member here posted for me that shows the neck diameter being .372" at the neck shouolder junction and .370" at the case mouth.

    I would get the gun chambered with a match quality reamer thats cut to the 338 Lapua specs , this way you will be able to shoot factory ammo if you get in a bind. As for the reamer being made for the 300gr SMK bullet , the throat section can be lengthened to seat the longer bullet out further with a throating reamer and if your gonna have this done you might want to check into what is a better lead angle this will help with pressure and accuracy. I think Kirby Allen did some test with diggerant throat leads with his Allen mag rounds when he was developing them.
     

  3. Perkules

    Perkules Well-Known Member

    Messages:
    179
    Joined:
    Dec 11, 2002
    [ QUOTE ]
    I have a loaded round diagram that another member here posted for me that shows the neck diameter being .372" at the neck shouolder junction and .370" at the case mouth.



    [/ QUOTE ]

    I´m measuring a factory (Lapua Scenar Moly) round at the moment and it shows .3715 at shoulder and .3695 at the case mouth.

    I´d stick with the factory specs as well.


    (I should do something about my TRG-S 338 LM, it´s been "re-stocked , under construction" for all too long. Nothing has happened, there is a carbon fibre stock of some kind but that´s it. When I finally got a rucksack full of Lapua brass and hundreds of different bullets - my stock broke. I miss it, sort of. It actually worked for a while. /ubbthreads/images/graemlins/confused.gif )