Cooper - Headspace?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by deertroy1, Oct 19, 2013.

  1. deertroy1

    deertroy1 Well-Known Member

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    In my post below I described having issues with trying to get my new Cooper in 7mm-08 to shoot.
    I've only shot new brass but have noticed some rounds show a bit more resistance chambering than others. On a whim I decided to measure the headspace with an RCBS precision mic. I realize these aren't the most precise tool to do this but it's all I have.
    What I found is that some of the new brass is actually about 0.001" - 0.002" too long. I find this to be somewhat unusual as I've seen factory rifles with too much headspace but never one with not enough. Most of the new brass measures the same or a tad more than my fired cases.
    Do you think this could be the cause of the so so accuracy I've got so far?
     
    Last edited: Oct 19, 2013
  2. CPGfan

    CPGfan Well-Known Member

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    My smith was telling me about another cooper that was brought into his shop with that same problem.
     

  3. deertroy1

    deertroy1 Well-Known Member

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    So did it cause poor accuracy in that gun?
     
  4. CPGfan

    CPGfan Well-Known Member

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    I'm not sure, just know that it shot great after he ran a reamer in it and the guy no longer had to beat the bolt handle closed with new brass. The question I had was if Cooper test fires all rifles and sends out a target with them, how did they not catch it?
     
  5. deertroy1

    deertroy1 Well-Known Member

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    Good question. Mine isn't that bad. It's hardly noticeable during closing the bolt. Most rounds close normally but there is just a slight resistance on a few rounds. However, I haven't found anything that will shoot yet.
     
  6. Mikecr

    Mikecr Well-Known Member

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    None of this is indicative of a Cooper rifle problem at this point.
    You should chill out, fireform some brass in it, and work up a good load -like everybody else.
     
  7. deertroy1

    deertroy1 Well-Known Member

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    I do not recall stating anywhere that it was a Cooper problem.......yet! Thus my reason for posting here and possibly getting advise from others with more knowledge and a different point of view than me before contacting Cooper.

    I don't have a go-gage so I can not be absolutely sure about the headspace problem. I do think factory rounds should chamber without any problem in a standard factory round that ammo is readily available for (not a wildcat or Improved).

    Your probably right about chilling out I guess my pateince is wearing a little thin after having returned this rifle once already because the first one had an issue with barrel runout (confirmed by Cooper).

    Hopefully the copper fouling will ease with more break-in. If not, that sometimes happens, I'll have to live with it. It doesn't mean I have to be happy about it however.

    Finally, Cooper has been great in their handling of everything so far.
     
  8. CPGfan

    CPGfan Well-Known Member

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    You did fine asking the question. It's too bad some members have an overbearing opinion on everything!! In the case I was telling you about, the smith did check headspace with a go gauge then ran the reamer in. Either it WAS a cooper problem or the smith had a bad gauge that he's built hundreds of 6.5x284's with and nobody was smart enough to realize there was a problem. My money is on a short chambered cooper. My post was not in any way degrading to cooper, everyone has a bad day and misses something. Just letting you know I had heard of that issue before. I don't know everything or claim to but I have never heard of factory rounds chambering hard in any semi custom production rifles either. Could happen I guess just never seen it.
     
  9. varmintH8R

    varmintH8R Well-Known Member

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    My Cooper M54 in 22-250 is definitely on the low end for headspace. I appreciate that as it means less sizing / less slop when FL sizing reloads. I personally never had issues with factory ammo or virgin brass in this gun, though..

    Cutting it close doesn't leave much room for error on Cooper's part - a couple thou puts it potentially into "problem" territory.

    I hope that you find you had a strangely long box of factory ammo - I know this rifle has already been a problem in a few different ways. Last thing you need is another.
     
  10. Mikecr

    Mikecr Well-Known Member

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    Is he shooting 'factory ammo'?
    Reading through the posts it looks to me like he's loading new brass, and concerned about results with multiple changes through only ~30-40 total rounds down a new barrel..

    Is it probable that Cooper, who only makes a handful of a handful of guns, screwed up 2 barrels for him in a row? Or that there is information missing from implications so far?

    I say once he's fireformed some brass, and put efforts into load development, things will look a lot better, or we'll have something to actually talk about here.
    Just my opinion, sorry if overbearing.
     
  11. varmintH8R

    varmintH8R Well-Known Member

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    That's a good question. I made that assumption based on his other thread that he linked to, where both handloads and factory fodder are being used.

    Deertroy1, are you getting the slight binding with virgin handloaded brass, factory ammo, or both?

    I'm a firm believer that any company can screw something up twice, so I'll hold judgement on that. That said, my personal experience is that when groups open from 1/2MOA to 2+MOA there is something other than ammo (scope, action torque, barrel float, operator error, etc) driving it. I have yet to have a rifle where tweaking ammo turned a 2MOA sprayer into a 1/2MOA tackdriver.

    YMMV, of course.......
     
  12. J E Custom

    J E Custom Well-Known Member

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    After reading all the responses, I will add my thoughts of what I would do if it were mine.

    First I would buy a head space gage ($35.00) and check it.

    And if this proved to be correct I would do a chamber cast to dimension the chamber, Reamers do wear and can lose there original dimensions by a few thousandths (A head space gage will not
    show this).

    If everything proves out, Then I would full length size all of my new brass before I load it checking it as I go in the chamber.

    In coopers defense: In an effort to produce an accurate rifle they may use a (Match Reamer) that is
    the minimum SAMME size leaving little or no room for error. and if the reamer has cut many chambers the diameter loss from a worn reamer could also be the problem.

    If you try a box of factory ammo and it does not chamber easily it is probably a issue with the chamber and touching it with a SAMME reamer should clear it up. But you would not want to increase the head space with the new reamer just enlarge the barrel of the chamber.

    Of course this is all speculation not having the rifle in my hands to check it.

    So my recommendation would be to verifier that there is not a chamber problem and then work
    on the sizing/loading process.

    J E CUSTOM
     
  13. deertroy1

    deertroy1 Well-Known Member

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    The slight binding is with both virgin brass and factory ammo.

    I have done no serious load development as I wanted to wait until I finished with Coopers recommended break in procedure. I also am hoping the barrel will ease up on copper fouling somewhat before starting any load development.
    I did, in all honesty, think the rifle may group better with the few handloads I tried. I also don't feel shooting fire-formed brass will bring a 1.5" - 2" gun down to under 1".

    A colleague in another province got a 7mm-08 about the same time I got mine and he also had to return his rifle to Cooper. He got it back and said that he finally got it to shoot but it took a whole bunch of trying different loads before he found one and only one that would shoot. He had ordered another Cooper but cancelled his order and is building a custom rifle instead. He said his rifle has the same long throat as mine.

    I also don't feel a person should have to be checking headspace or doing chamber cast on a rifle that cost over $2500? That's just my opinion and others may feel differently.

    My goal here is not to bash Cooper but to merely get some opinions. Maybe I'm expecting to much too soon etc. If this thread is coming a crossed as a degradation toward Cooper than please tell me and I'll see the moderators about having it removed. Cooper has treated me excellently and I want to do the same.
     
  14. Mikecr

    Mikecr Well-Known Member

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    What factory ammo have you tried?
    Aside from shear luck, the only thing that's going to get any gun shooting well for you is due diligence. You colleague should have learned, and you'll learn, one way or another.