Semi Custom Kimber Montana 280AI

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by ramrod79, Mar 25, 2014.

  1. ramrod79

    ramrod79 Well-Known Member

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    Guys just got done tweaking out my KM 280AI it has never been fired, and I wanted to know everyones thoughts on breaking my barrel in with regular 280REM rounds as they are cheaper , and I can fire form brass at the same time , should I expect or will there be any issues by breaking my barrel in this way , I mean I am only shooting 1 then cleaning.
     
  2. shortgrass

    shortgrass Well-Known Member

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    Go down to the "GUNSMITHING" section and read the thread titled ".280A.I. Concerns".
     

  3. MudRunner2005

    MudRunner2005 Well-Known Member

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    I've broken in 3 Ackleys while forming brass...Just be sure to shoot about 5, then let it cool down. Repeat for about 50 rounds. I usually make it an afternoon and take a few rifles and rotate them out so I keep something on the bench for shooting.
     
  4. shortgrass

    shortgrass Well-Known Member

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    Are those factory barrels or custom?
     
  5. MudRunner2005

    MudRunner2005 Well-Known Member

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    New factory barrels that have been rechambered to Ackley calibers. :cool:
     
  6. ramrod79

    ramrod79 Well-Known Member

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    Hey guys I am a little confused now after all the reading , as some say one thing ,and others say another, and now on top of it I have bought a Cooper 280 AI as well. So If I get the jist of things I will have to buy 2 sets of dies , and I cannot fire form 280 REM in the Kimber but I can fire form in the Cooper . The Nosler brass cannot be used in the Cooper but I can use in the Kimber, and Nosler loaded ammo can be used in both rifles. Boy Nosler created a mess in my opinion. Now I just need to find out who makes what dies ,and where to get them , I have a set of Hornady custom grade dies but I just have to find out what chamber they are for . Way to much work!!!!
     
  7. MudRunner2005

    MudRunner2005 Well-Known Member

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    Actually, Remington created the mess...Remington's custom shop started chambering rifles with a .014" shorter shoulder height based on a screw-up when they ordrered the reamer (that's what I was told), and that's where all the issues came from. And then somehow Nosler got involved in the screw-up, then they used that chambering for their SAAMI spec design, then blah blah blah, all this bullcrap later....And we're at where we're at now.

    Personally, if you're unsure which chamber you have for both, go buy a bag of 20 .280 Remington brass. Load 10 for each gun. Shoot the 20 brass, and keep them seperate from each other. Then measure headspacing of the fired brass, and you will have your answer.

    Or you can take both of your rifles to a competent gunsmith and have him check the chamber headspacing. If they come out the same, then you're good to go to buy Nosler .280 AI brass, and just FL size them each time, so it won't matter.

    But I also feel your pain of having multiple rifles in the same caliber. Which is why I keep seperate brass seperate for different rifles. And I write on the reloading label which rifle the brass was shot out of, so I know which is which. Plus, that lets me know which rilfe likes what load, so I makes me a (sort-of) load log book.

    Sounds like a pain in the ass, but it's not so bad once you get the hang of it.

    Plus, each rifle will like different loads, so I'd keep those brass seperate anyway, after fire-forming.
     
  8. shortgrass

    shortgrass Well-Known Member

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    I'd be completely surprised if Remington used a tool (a reamer), that was out sourced, before thoroughly inspecting it. It'd be just to expensive of a screw-up! No manufacture out sources much of anything without inspecting it when it comes in the door. I would be just as surprised if the reamer maker sent the tool out to Remington without inspecting it first. I'd call Kimber. Have the serial number of the rifle ready. They can answer your question reliably and definitively . If you want to shoot .280 Rem. ammo to break-in, and the chamber is the new SAAMI speced Nosler, the bullet needs to be "jammed" into the rifling so that the base of the case is firmly seated against the bolt face before firing. That info comes straight out of the new Nosler Reloading Manual. SAAMI standardized the Nosler chamber 2-8-2008
     
  9. Sully2

    Sully2 Well-Known Member

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    Its a PITA to start and continues to stay a PITA. Hence no more "AI"'s for old Sully. I got rid of mine
     
  10. MudRunner2005

    MudRunner2005 Well-Known Member

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    Yeah I know...And I added 2 more to the lineup. Guess AI's aren't for everyone. I look at them as a challenge, and I love a good challenge. Figuring them out is half the fun. Plus, the unique factor makes them cool to me. You don't meet someone everyday who has one and uses it. Half the people who have them get them handed-down and have no idea about them.

    I voluntarily went in head-first. And I enjoy it.

    You are right, they aren't for everybody. I guess I just enjoy it a little bit more than your average gun enthusiast.
     
  11. atrietch

    atrietch Member

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    I am in the same exact boat as the OP. I just picked up a new Kimber in .280 AI and was planning on breaking in the barrel with less expensive .280 rem ammo.
    Am I reading this correctly, that I can NOT fireform .280rem in it?
    I was told when I picked up the .280 AI that it would also shoot .280 rem.

    Thanks for any help or advise.
     
  12. MudRunner2005

    MudRunner2005 Well-Known Member

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    Buy a cheap box of .280 Rem and see if it will fit in the chamber. If the bolt closes, then you can fire-form them. Simple as that.
     
  13. shortgrass

    shortgrass Well-Known Member

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    .280 Remington cartridges will easily fit into a .280 Nosler A.I. chamber,,,, too easily! When fire forming the parent cartridge to an Ackley, the bolt should close with a slight resistance on the parent round. Ackley designed these like this so that the cartridge case would be firmly 'trapped' between the neck/shoulder junction and the bolt face. In the .280 Nosler A.I. chamber this will not be the case, the .280 Rem. round will NOT be firmly against the bolt face, or 'trapped', and firing it like this will be like firing a round in a chamber with exessive headspace. This is probably why azgutpiles' friend (from the "280 AI Concerns" thread) had a case head speration and has to seat the bullets into the lands when fire forming to avoid case head deformation. I'd have to have his rifle in my hands to find out for sure.
     
  14. yawn

    yawn Well-Known Member

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    IF there is actually a difference it is the reverse of the above. With the nosler SAAMI spec being supposedly .014 shorter then standard 280 rem will be tight in that chamber , not loose. And if that is the case then you should feel at least reasonable resistance closing the bolt if not very hard resistance.
    I say "IF there is a difference because" after physically checking quite a few different rifles Im not seeing anything like .014 difference. Not saying there isnt a difference just that Iv yet to see it.

    Mudrunners advice on firing some standard brass in both rifles and comparing is a good idea. Posting the results here would be very helpfull.
    Ill just add that Iv had a cooper 280ai for many years and fired nosler 280ai brass with over 10 reloads with no trouble at all. It does not stretch .014 as the theory suggests it should In fact it dosnt stretch at all.
    Head space on the brass is the same fired as it is new out of the box.