Chambering the 338 Edge

Discussion in 'Gunsmithing' started by alcesgigas, Dec 7, 2011.

  1. alcesgigas

    alcesgigas Well-Known Member

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    I'm building an Edge on a M70 action. It's soon to be barreled and chambered so now's the time to address this conundrum: Some of the hand loads, admittedly from individuals as applied towards their specific rifles, show COALs up to 4.00. These shooters are no -doubt purposely loading to these over-COALs to set their (ULD, VLD) bullet ogives a tested length that shoots best in their rifle (s). Kevin Wyatt of Wyatt's states that 3.85 is max length for the M70 using his MBE-8 magazine box. Is it possible to begin the rifling at a shorter length than normal (unknown what SAAMI chamber specs are for the Edge) so as to work from this--3.80--COAL? I'm thinking that there's enough powder capacity to begin testing at the usual lesser-than--maximum and work up to similar velocities with the same bullets as say a "normal" COAL?
     
  2. J E Custom

    J E Custom Well-Known Member

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    When building a rifle for a specific bullet you run the risk of it not liking that bullet and you are
    stuck.

    I recomend chambering to SAMMI specs. and tuning the load to the rifle. I am one of those people that have no fear of free bore. In fact I like it because almost any bullet can be made to shoot
    very well and pressure is not an issue so most of the time higher velocity is achieved because of it.

    Accuracy is also not an issue with free bore as long as head space is minimum (.000 to .001)

    I am in the process of testing a new cartrige and it has .100 thousandths of free bore and durring
    break in it was shooting 5 shot groups .381 and after break in it had dropped to .171 5 shots @ 100
    yards. These are fire form loads and and the cases are being expanded from 115 grains capacity
    to 122.3 grains. (an increase of 7.3 grains) and these loads are magazine length( 3.810 COAL).

    So my advice would be to chamber to a SAMMI standard and work up loads for the rifle.

    J E CUSTOM
     

  3. bassin93

    bassin93 Well-Known Member

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    Who has more experience with the 338 edge then Shawn at defensive edge and he seats his at 3.785 coal
     
  4. J E Custom

    J E Custom Well-Known Member

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    Probably no one.

    But he has reamer spec,s of his own and probably uses a particular barrel that works for him.

    Slight differences in reamer dimensions make huge differences in performance on different
    bullets.

    Also he has his way of setting the rifle up that can vary from other smiths.

    The seating depth depends on many things, so just to say seat your bullets @ 3.785 would be
    miss information and could lead to problems if the rifle is not set up the way he does it.

    This is no difference on any rifle.head space, throat depth. lead angle. bullet type, load type
    and pressure required to achieve a targeted velocity, all come into play.

    J E CUSTOM
     
  5. alcesgigas

    alcesgigas Well-Known Member

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    Thank you both. So I should ask what the COAL is/as machined into the barrel (chamber size)? That makes sense.
     
  6. bassin93

    bassin93 Well-Known Member

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    buy the reamer from PTG for the spec you want, they have several prints that they will send you and then you can make up your mind which reamer with the different throats you want for your coal.
     
    Last edited: Dec 9, 2011
  7. Topshot

    Topshot Well-Known Member

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    There is nothing wrong with loading to magazine length so long as the bullets shoot. I have found with the new Bergers that I can not.
    With this bullet I must have them into the lands when using Retumbo.

    For the person with a .338 Edge that single loads, there are changes ahead that may make for some interesting times.

    Look for some advances over the next six months that will provide for significant change.
     
  8. alcesgigas

    alcesgigas Well-Known Member

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    Thanks b93. Topshot, from down under, my eyebrows are up, my attention you've got! I suspect you are referring to Shawn Carlock's Edge+P? I figure I can single load and for my kind of hunting with this rifle that's just fine, but since I have a magazine cut-out I might as well use it when I can.

    Your comment regarding the Bergers intrigues me as your whole response indicates mystery ahead. Care to explain? Have you used 300SMKs and if so did you experience the same necessity--that they must contact the lands? I assume you've used a chronograph, checked for high pressure signs, and closely monitored group size at different ranges--care to share? Thanks for your commentary--I think. :D
     
  9. Topshot

    Topshot Well-Known Member

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    I found the SMK's fine to jump. But with the Bergers (in my rifle) they needed to be into the lands for best accuracy.

    As for future developements, well just stay tuned. Can't say too much.

    In the mean time just enjoy what the .338Edge has to offer. It is an excellent cartridge within its limitations. But that may change soon. :D