chambering for 300rum for long coal?

Discussion in 'Gunsmithing' started by dodgefreak8, Nov 19, 2013.

  1. dodgefreak8

    dodgefreak8 Well-Known Member

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    I plan on loading the rounds for my upcoming build with the longer bullets from nosler and berger and i was wondering if there is something specific I need to discuss with my Smith in regards to the chamber reaming?
     
  2. digger11

    digger11 Well-Known Member

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    I would make it clear to the smith that you want the loaded rounds to fit in the magazine/clip and function in the action. Throat accordingly.
     

  3. dodgefreak8

    dodgefreak8 Well-Known Member

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    I plan on using the Seekins dbm for 338 lapua if i can get my hands on one. I am having the stock inlet for it. That should allow a coal out to 3.9". Not sure what the loaded rounds length will be though....
     
  4. trebark

    trebark Well-Known Member

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    You need to load a dummy round (as long as you can that will still fit in your mag). Then send that to your smith and tell him you want it throated so that the rifling is .010 off the ogive of the bullet (or however far off you want)
     
  5. dodgefreak8

    dodgefreak8 Well-Known Member

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    That was my first thought but the problem is how do I know what round the rifle or I will like best? I hate to have the chamber cut for a 215gr Berger and find out the 210 gr LR ACCUBONDS shoot better. I'm assuming the ogive of these two rounds are fairly different...
     
  6. trebark

    trebark Well-Known Member

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    This is the roll of the dice you take!
     
  7. Hired Gun

    Hired Gun Well-Known Member

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    I have had extraordinary luck with the regular Sammi spec chamber. The freebore is pretty long on it as they are designed. If it's not long enough just shoot a hundred rounds and check it again. The 300 Rum is hard on throats. If you build it extra long it won't be long and you will run out of magazine. Another good thing is both the Berger and the Noslers are very forgiving for distance off the lands.
     
  8. dodgefreak8

    dodgefreak8 Well-Known Member

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    WOW! I knew the ultra was a bit of a barrel burner but i had no clue 100 rounds would have a noticeable affect on the throat! Maybe i should just have it chambered to specs. Thanks
     
  9. Hired Gun

    Hired Gun Well-Known Member

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    I have scoped them at 40 rounds and witnessed 1/2 inch of erosion. Both times the guys were having meltdowns and just shot 40 in a row with no cooling and just wrecked brand new barrels. The 300 Rum without a brake can be hard to master. If you keep them clean and cool I have seen 200 rounds with minimal wear. Even my 300 Wby has significant evidence of being used at 400 rounds.
     
  10. shortgrass

    shortgrass Well-Known Member

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    Throat erosion begins with the first round. Much of how fast it progresses depends on the user. I'll second going with a SAAMI speced chamber.
     
  11. J E Custom

    J E Custom Well-Known Member

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    And I will third that !!!!

    J E CUSTOM
     
  12. dodgefreak8

    dodgefreak8 Well-Known Member

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    Thanks for all the input! Guess i will stop over thinking this build lol. I'll go with the spec'd chamber.