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Reforming Brass

waltermoewaltermoe Member Posts: 1,775 ✭✭✭✭
Does any one know of a sight that has instruction on how to reform brass from a smaller case to a larger.. I haven't done any in 45 years and the mind is a little foggy.


  • waltermoewaltermoe Member Posts: 1,775 ✭✭✭✭
    edited November -1
    I have been reloading close to 45 years now, rifle, pistol and have dabbled a little with shotgun, but I have never reformed brass before. I acquired some Winchester 8x57mm brass and would like to size it down to 7x57mm. Use to be able to buy Winchester brass in 7x57mm but I don't think they make it anymore. I don't know if just trying to run 8x57mm through my 7x57mm die will work, I don't want to get a case stuck, so I thought I would ask if anyone tried this before? Dimension wise the cases are about the same, also these are brand new cases so brass should be fairly soft.
  • charliemeyer007charliemeyer007 Member Posts: 6,579 ✭✭✭
    edited November -1
    Its like they run some every once in a while before the great ammo shortage.

    They will size down nicely. Depends on your chamber if they will be to thick in the neck and require some form of thinning. Going up from 7 to 8 that problem never comes up.

    I would use a q-tip and lightly lube the inside of the neck with the Lee case lube. After case forming, I'd fire form with a cast bullet load. Then trim for uniform length, flash hole de-burr, inside and out champfer then neck size if the chamber will allow that.
  • jonkjonk Member Posts: 10,121
    edited November -1
    The main issue will be that on occasion, you may get some wrinkles in the neck or shoulder; these will fireform out no problem. Otherwise, size, trim, and done.

    Most military chambers are big enough and most Winchester brass thin enough that you shouldn't need to thin the necks.

    I would NOT anneal. Opening up a case, annealing is great. Sizing one down, usually leads to crumpled shoulders.

    If you have a bunch to do, get an RCBS form and trim die. Cat's meow for doing this, I've done a tone of USGI brass to both 7 and 8mm that way.
  • Ray BRay B Member Posts: 11,822
    edited November -1
    In reducing the case diameter I've found it best if the portion of the die that will be contacting the neck has an angle of less than 30 degrees and 25 degrees is even better. This is usually the shoulder portion of the die. the steeper angle tends to crush the neck whereas the shallower angle pushes the case into the smaller diameter. Since the 7x57 has the shallower angle, I'd expect the resizing die to do the job well without the need to get special reforming dies. I would use resizing lube liberally on the portions being sized.

    Another option is to reduce them sequentially. A 308 or 30-06 sizing die, with the expander button removed will work. Take the 8x57 case run it through the 308 or 30-06 sizing die enough to neck down at least a portion of the neck (with the 30-06 die) or partially set the shoulder (with the 308 die). This will reduce the amount of forming to be done by the 7x57 die.
  • waltermoewaltermoe Member Posts: 1,775 ✭✭✭✭
    edited November -1
    I like the idea of starting with a .308 die. It is only about .007 smaller than the 8mm and has the same shoulder angle, that's a good idea, thanks Ray B. Now as far as thinning the neck I may have to do that, it's a custom barrel I ordered from Shilen years ago, but I'm set up for that. Again thanks for all the tips.
  • MobuckMobuck Member Posts: 13,684 ✭✭✭✭
    edited November -1
    Midway USA has Norma and Nosler 7x57 brass. Winchester 7x57 is listed as "seasonal run" so will be available at some time. Depending on case loss from the reforming, you might be about the same cost to buy 7x57 and sell the 8x57(fair market for that now).
  • Alan RushingAlan Rushing Member Posts: 9,002 ✭✭
    edited November -1
    IF there is an actual need to do so to reform It's simple enough - and the advice/pointers given are on target and real.

    But as Mobuck states: "Midway USA has Norma and Nosler 7x57 brass. Winchester 7x57 is listed as "seasonal run" so will be available at some time. Depending on case loss from the reforming, you might be about the same cost to buy 7x57 and sell the 8x57(fair market for that now)."

    There is a decent market for what you have in hand now, and for a decent Price to the seller, you ought to be able to turn that brass to cash, if wanted.

    I've used all sorts of brass from all sorts of manufacturers. I've as yet not found any brass that will beat Norma brass - and most will not come anywhere near Norma brass in quality and uniformity. (JMHO)

    (( There are only two or three that might be comparable - depending on who is asked and what their criteria is and what their expertise/experiences might be.))
    In other words NORMA brass is top-notch.

    Let us know which way you go and how it works for you!
  • rsnyder55rsnyder55 Member Posts: 2,526 ✭✭✭
    edited November -1
    Another vote for Norma Brass. I believe that is what Weatherby uses or used to use. Still using brass I bought in 1986.
  • nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1

    Yes, Norma and especially Lapua brass is considered to be head and shoulders above Winchester but you have the Winchester brass in hand so I would run with what you have. Besides it will save you a ton of money over the other two...

    Simply neck down the 8mm to .308 using an intermediate sizing die as suggested. Then full length resize with your 7x57 die. Using case lube is required. I use Imperial Sizing Wax because it requires so little and is manageable, but I have also used powdered graphite with good results as well. Either way, be sure to clean your cases thoroughly after processing for size. Then do the primer pockets, flash holes, trim and chamfer or whatever your standard is.

    There is no need to use lead bullets for fireforming since there is little brass movement in the case. Load for accuracy testing and go to the range and enjoy the experience!

  • victorj19victorj19 Member Posts: 3,642 ✭✭✭
    edited November -1
    I have an old reference saying to run lubed 30-06 cases in a 7mm Mauser die. Haven't tried it yet but I would rather run them through a 7mm form trim die and trim the case length and clean it out before using a 7mm sizing die.
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