7mm am

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Gator26, Dec 27, 2010.

  1. Gator26

    Gator26 Well-Known Member

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    can a rem 700 sps 300 rum be rechambered to 7mm allen mag?
     
  2. nddodd

    nddodd Well-Known Member

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    A 300 rum is a .308 dia. bore and a 7mm allen mag is a .284 dia bore so no you couldnt but you could order a new .284 dia barrel and have it chambered to a 7mm allen mag.
     

  3. Gator26

    Gator26 Well-Known Member

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    yeah i understand the barrel isnt going to work i just didnt know if there was and issue with the action or not. /
     
  4. nddodd

    nddodd Well-Known Member

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    They claim that the action isn't strong enough becouse tge Allen mag is based off of the lapua case, but Remington makes a factory gun in the lapua round so go figure. Kirby Allen is the man to ask goes by fiftydriver on here.


    Nathan
     
  5. Gator26

    Gator26 Well-Known Member

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    thanks for all the help and info nathan
     
  6. royinidaho

    royinidaho Writers Guild

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    I'd kinda shy away from that idea.

    Run it by Kirby though as that's the only way your gonna get a 7mm AM. :)
     
  7. pyroducksx3

    pyroducksx3 Well-Known Member

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    I copied this from Kirby's post on myths of overbore cartidges. It's his personal hunting rifle

    7mm Allen Magnum
    160 gr Accubond @ 3414 fps
    Rem 700
    Lilja #3 SS 1-9, 26.5" Finish length
    DE 1/2" brake
    HS Precision sporter stock, green with black web
    HS Precision DM system
    Tuned Rem 700 trigger
    Leupold Mk4 FFP 3.5-10x 40mm w/ TMR reticle
    Anything packing rifle
    Weight: 10.0 lbs ready to hunt with

    He goes on to say somewhere that its better to use a custom action because they have much tighter tollerances and can be taken to higher pressures. So this would lead me to believe to take full advantage of the AM use a custom action. He does state that he doesnt feel the need to take his rifle as hot as others do though. It would be best to ask him though. I know that he isnt building rifles off of anything but custom actions anymore, trueing the rems slowed him down to much, so Im not sure if its even possible unless you have it done somewhere else and then to him to have it chambered. Also since you cant take it to its full potential in the rem action Im not sure if its really anybetter than the 7 RUM in that action. Again goo dquestion for Kirby
     
  8. Gator26

    Gator26 Well-Known Member

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    do you think it would be cost effective to use a 700 action that i allreay have or would it just be better all around to buy a custom action and go that way? such as a big horn action? or there is allways the idea of just building the rifle how it is in 7mm rum.
     
  9. pyroducksx3

    pyroducksx3 Well-Known Member

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    I talked with kirby and he said if you had no action to start with its best to just get a custom, because by the time you get the action blueprint it and do everything you need it ends up costing about the same. Vs Just starting out with a better quality product. I would say if you really want an AM you want to be able to use that cartridge to it fullest potention get a custom action. A lot of people use lawton and stillers actions have been recommended as well.
     
  10. Ridge Runner

    Ridge Runner Well-Known Member

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    Does kirby still build off production actions?
    Read a post by him awhile back that stated that since he was so busy he just couldn't take the time to blueprint a production action so it was custom actions only.
    RR

    But yes it'll fit, ya just need to use a badger ord. sako type extractor, Kirby built me one 4 years ago.
    RR
     
  11. 7MilMauser

    7MilMauser Member

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    What kind of barrel life can be expected by a cartridge that holds over 100 grains of powder? My guess would be 500-700 rounds? Is this right?
     
  12. royinidaho

    royinidaho Writers Guild

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    Way more than that! I was anticipating 1000 rounds out of a 270 AM.

    It's at about 900 now and bore scope suggests it looks, per a smith's guestimation, like about 500 rounds out of a bench rest barrel.

    I'm happy with that.
     
  13. Gator26

    Gator26 Well-Known Member

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    thanks for all the info guys , i guess it looks like ill have to look into geting a differnt action.
     
  14. azsugarbear

    azsugarbear Well-Known Member

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    In short - yes, it can be done. I have a 277 AM (338 LM parent case) built on a Rem 700 long action that came with a standard magnum bolt face. Kirby built the rifle, so I know it can be done.

    The problem is the bolt face itself. Most magnum calibers require a bolt face of .531-.534 in diameter (including the RUM's). However, the Allen Magnums are based on "fatter" cases that require even larger bolt faces than standard magnums. For example: the 270 AM is based on the 330 Dakota case (.545 bolt face). The 277 AM is based on the 338 Lapua case (.588 bolt face). In order to build an AM on a std. Rem. magnum bolt, you need to open the bolt face to accommodate the "fatter" cases. This is done by removing material from the bolt face and opening it up. The Dakota isn't too bad, but the 338 Lapua is so fat, that there is little material left around the outside of the bolt face - making it weaker (or at least the weak link). my bolt face has just a thin rim of metal around it.

    While it functions fine and is safe to fire, it probably is not ideal for anything based on the Lapua case. I have heard that many gunsmiths simply will not do it because they cannot/will not be able to guarantee the strength of the bolt. Kirby has done them, but as others have mentioned - time may have become so tight that he no longer wants to mess with them.