Forster Co-Ax press

Discussion in 'Ammunition & Reloading' started by Greenbug, Dec 5, 2011.

  1. Greenbug

    Greenbug Active Member

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    Has anyone out there used one of the Forster Co-Ax presses for reloading?

    I am noticing more and more that my brass after re-sizing is not straight, and I think that this press might cure that problem. It's kind of expensive to just go out and buy one without doing a little research. I've watched a couple of the youtube videos on it, but would like some first hand experience from someone before I buy one. Or are there any other tricks to alleviate the problem of crooked brass. My problem seems to be random, some cases come out pretty straight, others wobble like crazy when I chuck them up in the Lee case trimmer.

    Any help or suggestions would be much appreciated.
  2. padd54

    padd54 Active Member

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    I use the Lee universal holder, one with the jaws, and often need to spin the case or open and close the jaws a few times before the case is seated properly. Do you have a way to check concentricity?
    Perhaps try chucking one up and spin before you size it and then again after you size to see if there is a difference.

    What press are using now?
    What brand dies?
  3. Greenbug

    Greenbug Active Member

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    I am currently using a Redding Big Boss II press and Redding dies. The Lee trimmer I use is the caliber specific one that I chuck in a cordless drill. I have tried to spin test before and after sizing, it seems completely random. I've even made sure the shell holder on the press is in the same orientation during these tests. The caliber/case size dosen't seem to have anything to do with it as I get similar results weather I'm doing handgun cases short rifle case or long rifle cases. It's perplexing to say the least.
  4. padd54

    padd54 Active Member

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    If all you are going by is the wobble while using the lee trimmer, I wouldn't worry about it.

    Lee is not known for tight tolerences. Have you simply rolled the case on a table top?
    I think the Lee holder is your weak link.

    Have you seperated the wobblers from the good ones? Then go ahead and load them exactly the same, is there a difference in accuracy? After all, accuracy is the name of the game.

    Good luck,
    Ray
  5. Greenbug

    Greenbug Active Member

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    I know that Lee isn't known for "precision" as their name would imply, I just thought the randomness of the cases wobbling in the case trimmer was unsettling. I don't see it affecting accuracy wich is strange now that you mention it. Maybe I'm trying to fix a problem that dosen't exist?

    If the accuracy isn't affected, then I probably shouldn't worry about it right? I guess it's more annoying than anything (the wobble). When I am prepping my brass I usually full length size then chuck them up in the case trimmer. First step is to trim to length, then while the case is still in the chuck I'll inside and outside deburr the case mouth, and finally I'll deburr the inside of the primer flash hole. Once all this is done then I uniform the primer pockets. The annoying wobble sometimes causes the case to jump out of the chuck while performing these functions. I thought that the wobbly cases were not only annoying, but a symptom of a larger problem with the press, sizing die or press shellholder? I guess I worry to much...
  6. deadshot2

    deadshot2 Well-Known Member

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    The Forster Co-Ax is certainly a fine press but probably not necessary.

    The Lee trimmer case turning tool is not a good way to check concentricity of a case. If there is the slightest burr on the head of the case it will cock it in the tool giving the illusion of a crooked case.

    If concentricity is a concern, I would first check a finished cartridge on a concentricity gauge like the Hornady. If you have an issue then take a look at your sizing die(s). When a case is sized the case is squeezed back to original size and the case neck is undersized. When extracting the case from the die the expander then forced the brass outward to a finished dimension of .002"-.003" smaller than the bullet diameter. When this expander is being pulled out it can actually make the case neck "crooked". The "ball" will follow the side of the case neck that is thinnest/weakest. Some dies use a more tapered expander which keeps the case neck straighter. Surprisingly enough, the Lee Collet Die is among the best for making straight cases if you are neck sizing only. It forms the case neck around a mandrel rather than "squishing" the case neck then pulling an expander back through to get the right size. For regular full length sizing dies improper lube of the case neck can cause problems. If the expander drags unequally on the sides of the neck a crooked case can result.

    The above also makes a good argument for Case Neck Turning and annealing.

    In summary, I wouldn't jump on another press yet, I'd check first to see if I really had a problem by checking the finished ammo for run-out.
  7. Woollymonster

    Woollymonster New Member

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    Greenbug,

    The Co-Ax is a great press. I own one along with the Big Boss II such as yours. I have been using them both side by side for several years now. I also have an old USA Made Rock Chucker.

    I have not been able to confirm that the Forster press/dies make any more accurate ammo than the Redding. There are some attributes of each machine that I prefer over the other but when using the top of the line dies from each company, I get the same results as far as accuracy is concerned. To answer your question; I just sent 200 rounds of Federal Premium 308 brass (once fired) through the Forster FL sizing die and I still get as much as 4 thou runout on a concentricity gauge. And they wobble on the case turner just like yours. I use KM and a 21st Century neck turners.

    I have come to this conclusion by both shooting the ammo and by measuring the case dimensions. I use Sinclair Concentricity gage, neck thickness gauge and a Neco tool. I have used all kinds of brass and still get this "banana" effect after shooting regardless of the press, dies and brass used. David Tubb talked about indexing his cases with a Sharpie and orienting the case the same way in the chamber each time.

    But by all means, if you have the means, you will love the Forster press. It has a lot of power and the self centering case holding system is great. You will never smash a case mouth into the bottom of the die again or hunt for shell holders. I find I load faster and do some other operations such as de-capping better with the Forster.

    As far as getting the cases perfectly on plane and on axis (concentric), I'm still searching for the answer.

    Cheers,
    Woolly
  8. deadshot2

    deadshot2 Well-Known Member

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    If you are getting this "banana" effect after shooting, I personally would suspect the bolt face isn't true to the axis of the chamber. When the round is fired the case head is aligned to the bolt under 50,000-60,000psi on average and this will certainly cause case wobble in a neck turning case holder that grips the head of the case.

    If you follow David Tubb's advice and index the cases this will mean that the case head won't be "bent" in a different direction and can contribute to accuracy. If it were my rifle I think I'd check the bolt face. Do the "Sharpie Trick" where you black out a case head and then chamber it If you do this with a dummy round, bullet seated far enough forward to jam into the lands, you'll see if there is one side of the case head that gets "wiped" more than another. Even if the bolt has been "trued", it can still have enough runout to cause some case runout issues.
  9. RVTECH

    RVTECH Well-Known Member

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    I really like my Co-Ax. Got mine a couple years ago and wish I had done it sooner. The old Rock Chucker now is just the rifle brass resizing press. The Co-Ax takes some getting used to but once you do, and get things adjusted properly it is accurate and much faster than a standard single stage style. There is no free lunch though as it does not have the ram priming system such as the RCBS but if you have already moved on to a hand priming tool then it is not a problem. As far as your original problem I do not believe your press is the problem. There is really not much to affect alignment of the case going into the die other than ensuring the die is locked properly and not slightly canted due to a worn ring or bad lockup. Make sure your shell holder is seating all the way into the slot and check your 'ram' for wear. Mine is pushing several thou of movement now but still resizes accurately.
  10. BAR338LM

    BAR338LM New Member

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    I have a Co-Ax press and you can do every thing on it including priming and when you prime with them. It puts them in the proper depth every time. I could not be happier with it, and you don't have buy a bunch of shell holders. It uses one of two shell plates.
  11. Greenbug

    Greenbug Active Member

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    I ended up getting a Forster Co-Ax and I do not regret it. It is easily the finest single stage press I have ever used. I determined that the random case wobble in the Lee case trimmer was due to brass rim thickness inconsistencies and or burrs on the rim of the cases. I checked runout on rounds loaded on the Redding press versus the Forster and the difference was neglegible with a slight advantage going to the loads assembled on the Forster Co-Ax press.

    That Forster is so smooth I don't know how to explain it. It adds to my reloading enjoyment using such finely crafted equipment!

    Saw that this thread kinda came back to life and thought I'd give an update on the original question/problem.
  12. RVTECH

    RVTECH Well-Known Member

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    Just make sure you get all your dies adjusted properly to just touch the shell holder plates or you may bend the shell holder mounting bracket (I did) and had to straighten it. Like I said though once you get used to it your reloading will speed up noticeably. Keep the shell holder assembly clean and free of case lube (if you use it) and you can get through 100s or rounds without having to clean it. Like I said definitely a learning curve with the Co-Ax.