Fire forming help

Discussion in 'Reloading' started by j3564wost, Oct 8, 2018.

  1. j3564wost

    j3564wost Well-Known Member

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    Fire forming brass for my 6.5-06ai for the first time ising the cream of wheat method and I'm running into some issues...
    Starting with 25-06 brass I've tried multiple different powders and powder charges with the same result, primers pushed out. Some of the primer pockets seem too loose when I resize to load, they can be almost pushed in with my fingers. There are no markings on the case as if overpressured.

    Any advise???

    Thanks
     
  2. j3564wost

    j3564wost Well-Known Member

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  3. MudRunner2005

    MudRunner2005 Well-Known Member

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    I don't use the COW method... I use the live-fire method, where I load up a light charge (usually about 5 grains less than a book starting load) of rifle powder (usually RL-19 or RL-22) and a cheap Hornady Interlock bullet and a cheap CCI primer. I seat the bullets touching the lands (slight bolt pressure when I close the bolt) so I know its properly seated against the bolt face and the lands, and will properly form to my chamber. Then I shoot 5, let it cool. Shoot 5, let it cool. I usually do about 50 per session, and with properly formed AI brass (from good quality brass), they should last a good while if you don't load them super hot.

    Also, you're using .25-06 brass. When forming for an AI chamber, when the brass gets fire-formed, it scavenges brass from somewhere as the brass flows to fill the chamber walls while forming. This brass will mostly come from the neck length. Example.. I tried forming .25-06 AI brass from .25-06 Rem brass, and the necks came up 0.020" too short. So, i started forming using .270 Win brass, that I FL sized in a .270 Win die, then necked-down to .257 in my FL .25-06 AI die. Then I trim the necks 0.020" too long, and when they fire-form in my chamber, they come out at a proper 2.494" length.
     
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  4. can1010

    can1010 Well-Known Member

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    if using the cow method you need to use a false shoulder with a tight bolt close to hold case tight to bolt face to form properly. looks like primers backed out from too much headspace and low pressure not forming case properly. also MUDS idea of using 270 cases is better than 25-06
     
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  5. ramrod79

    ramrod79 Well-Known Member

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    Use 270 brass neck up to 280 size down to 6.5 to get a false shoulder you should get light crush on shoulder when you close bolt. Then do your COW will form up real nice. Then use a light load for first firing to form out rest of brass like 1-2 gr light.
    Or use 280 brass size down 3/4 of neck to get false shoulder the use COW.
    There are lots of guys who use live rounds and the jam method I’m just not one as I’ve never tried or seen done so I use COW.
     
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  6. MagnumManiac

    MagnumManiac Well-Known Member

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    I agree, necking DOWN is a much safer method than necking UP. Necking up thins the case neck walls, it’s not a lot, but it’s there.

    I use the COW method, always have, the last time I fireformed 375 Weatherby from 375H&H I put candle wax in the case mouths because I was travelling 4+ hours from home and thought it would help stop any settling.........boy was I wrong.
    After firing 20 rounds, I noticed bolt close was getting tighter and the next 5 rounds were also harder to extract. Knowing I only had an additional 5 rounds to fire, I proceeded to do so, getting stiffer and stiffer extraction........those last 5 cases all showed ejector marks and having no cleaning equipment I decided to ‘clean’ the barrel by firing a 260gr Accubond round hoping it would clear the candle wax by burning it off.
    Didn’t work very well, not sure how, but it was evident there was wax in the chamber too, causing the stiff bolt close/opening? I will never use wax again!

    Anyway, when using COW, I usually oil the cases if they aren’t belted, this way the case head meets the boltface very early in the burn and the forward part forms to the chamber WITHOUT stretching in front of the web.
    If an AI chamber is cut correctly, there should be a .005” NEGATIVE HEADSPACE in the chamber, hence no NEED for false shoulders, jamming bullets or other funky gimmicks.
    Another thing, using COW will not get you completely formed cases, an additional firing with a loaded round is generally required.
    If you oil (lightly) your cases, your backed out primers will stop, or you can increase the charge weight until the problem goes away.

    Cheers.
     
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  7. j3564wost

    j3564wost Well-Known Member

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    Magnum,

    I've read where guys have "oiled" there cases but I never fully understood what they were saying. I will have to give it a try. I assume they are just coating it with a light gun oil?

    Also thank you everyone for the help!
     
  8. MagnumManiac

    MagnumManiac Well-Known Member

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    Yes you can use gun oil, but I prefer to use a spray oil like WD-40 that you can buy as a non aerosol lubricant.

    Cheers.
     
  9. bigedp51

    bigedp51 Well-Known Member

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    Oiling your cases will double your bolt thrust and you are warned not to do it in the reloading manuals and firearms manuals,

    [​IMG]

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    Below running your AR15 too "WET" and the oil getting into the chamber and its added bolt thrust.

    [​IMG]

    The British used the base crusher method of taking chamber pressure readings. They used a hollow copper crusher that allowed the firing pin to pass through the copper crusher. And they had to oil the cartridge to get a true chamber pressure reading, Below is from the 1929 British textbook of small arms.

    [​IMG]

    A dry case grips the chamber walls and acts like a shock absorber and reduces the amount of bolt thrust and the dwell time the case pushing on the bolt face.

    Bottom line, oiling your cases will cause double the bolt thrust on you locking lugs and is a very bad idea.

    [​IMG]

    If the ammunition companies wanted the cases lubed they would come that way from the factory.
     
    Last edited: Oct 10, 2018
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  10. Bravo 4

    Bravo 4 Well-Known Member

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    I started oiling my cases to fire form using a light powder charge and COW (with false shoulder on case). The pressure isn’t enough to form the case 100%. Don’t think this is quite the same as running a “standard” pressure load with some form of obstruction (liquid) in the chamber as described in those manuals. That I would agree can potentially cause problems.
     
  11. shortgrass

    shortgrass Well-Known Member

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    If your chamber is properly head spaced for the Ackley Improved, you need to be necking down new .270 Win brass . Start by running your 'lot' of .270 brass so that the neck is sized half way down its length using your 6.5mm sizing die. Next, adjust the sizing die so that when your sized case gives resistance to closing the bolt. There, you have the cartridge case "trapped" between the bolt face and the neck/shoulder junction of the chamber. Next, load a couple or three your prepared case with a moderate charge for the bullet listed in a loading manual. Measure the neck diameter of those loaded cartridges. You need a minimum of .003" clearance here, the neck diameter being at least .003" smaller than the neck in the chamber. There is no need to 'jam' the bullet if your cases are properly sized. It takes chamber pressure to fire form brass, and with the COW method it will take more than one firing to fully fire form the brass. Why isn't the gunsmith that chambered this barrel for you not helping you with fire forming brass if you are unfamiliar with the process? IF the chamber is properly head spaced there is no need to "jam" the bullet or oil cases. Oiling the cases can create dangerous conditions up to an including catastrophic failure of the rifle. A very good reference for Ackley head spacing can be found on https://mansonreamers.com
     
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  12. MagnumManiac

    MagnumManiac Well-Known Member

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    There is NO NEED for a false shoulder, the AI chamber uses the -.005” headspace so the neck/shoulder juncture controls headspace forcing the case head against the bolt face. If you chamber an empty NEW case and find NO RESISTENCE, that is when and, only when, a false shoulder is required.
    This additional step should not be required if the chamber is cut correctly.

    Cheers.
     
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  13. shortgrass

    shortgrass Well-Known Member

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    He has to make brass. It is possible to push the shoulder back far enough that there is no ".004 inch crush" of the brass when closing the bolt on a case that has been necked down. I did not suggest creating a false shoulder. What I did say is that there needs to be resistance closing the bolt on a necked down case to insure that the case is 'trapped' between the bolt face and the neck/shoulder junction of the chamber. By the way, check P.O. Ackleys' book, he suggests .004" shorter than GO.