Wrestling the .284 DONUT!!!

Discussion in 'Big Stuff--7mm, 30 Cal, .338+' started by doninreno, Nov 25, 2019.

  1. doninreno

    doninreno cheap old fart Silver $$ Contributor

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    Seems like there are a lot of people that are having or have had problems with donuts appearing in the 284 brass after a use or two, which can be a big problem with the longer bullets---particularly if the brass was necked back up to 7mm from a 6.5 -284 case. What seems like to me works from experiences of friends is to have the free-bore lengthened out to maybe as long as .250" in order that bullets can be seated off the lands a ways if required and still not be on or even really close to the donut inside the case. That also seems to not affect accuracy much at all and is a way to deal with the donut problem---just go longer on the free-bore and ignore the donut.

    So, what kind of solutions have you all found that work? i'm gonna bet that there are some good solutions floating around out there that work fine and DO NOT require a bunch of fooling around with brass. Any comments/ideas/solutions any of you can pass along? I'm open to trying jsut about anything that seems to relieve the problem, especially if makes accuracy decent!
     
    Last edited: Nov 26, 2019
  2. rardoin

    rardoin Silver $$ Contributor

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    I am in the same camp as your friends....run a long enough FB to keep the bullet's bearing surface above that area and 'let her eat'. A .230" freebore and longer will keep the bearing surface of any common bullet currently out there (A-tip 250 excluded) safely ahead of any donut that will form. I have a .225" FB chamber and it is fine for the 184 Hybrids...but just makes it. If I would regrind my reamer I would go to at least .230".
     
    Last edited: Nov 26, 2019
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  3. F Class John

    F Class John NRA Life Member Gold $$ Contributor

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    One option is Blake’s new IDOD will trim them out lickety split. I’ve also used a gage pin with the sharp edge facing down and quickly sheer the donuts out. Works great. That was when I used Lapua and necked up. I’ve used the Peterson most of this year which is a straight 284 and find the donuts are almost a non-issue so far.

    In any case I seat above them anyway.
     
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  4. Scott Harris

    Scott Harris Silver $$ Contributor

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    We use no-turn brass and get a donut on the first firing. FB is .250 and our 180 hyrids are a good .060" above the donut....it has no effect.
     
  5. Bc'z

    Bc'z Gold $$ Contributor

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    Seems I've read here to size your brass and go a couple thou smaller and use a mandrel to push the doughnut to the outside with a mandrel them trim necks.
    Or just send it to djsbrass
     
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  6. Rope2horns

    Rope2horns Norm Harrold Silver $$ Contributor

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    We use Lapua 6.5x284 necked up....no turn cases have a donut in every case...neck turned cases (.313nk) have zero donuts.

    My wife shoots a straight 284 no turn, with 184 Berger's and a 220fb with zero issues. Bullets are in front of the donut.
     
  7. doninreno

    doninreno cheap old fart Silver $$ Contributor

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    DJ's Brass hydro forming didn't seem to make any difference at all with my 6mm BRX cases...they had donuts that were noticed during the case prep for the second firing after having been hyrdro formed from LAPUA 6mm BR Norma cases.
     
  8. Bc'z

    Bc'z Gold $$ Contributor

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    I was suggesting to have DJ's do a full prep on the brass pushing the doughnut to the outside and turn necks to remove, versus doing it yourself.
     
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  9. Sniper338

    Sniper338

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    So why hasnt anyone ditched lapua and went to peterson 284 brass? Thats my plan once my norma brass goes. No reason to nevk up lapua anymore.
     
  10. Straightshooter1

    Straightshooter1 Gold $$ Contributor

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    Whether it's the pressure from being fired or from water, the pressure is equal on all parts of the interior of the case and so will not remove things like a donut. It either has to be cut out, or. . . it can be squeezed flat with something like a collet die where the die squeezes against any high spots and then against an anvil. The brass is relatively soft to where the material of high spots are squeezed into the rest of the neck. When this is done, the thickness of the neck tends to grow accordingly. Turning the interior of the necks and cutting the donut out would keep the thickness of the necks from growing like it does if one uses a collet die.
     
  11. doninreno

    doninreno cheap old fart Silver $$ Contributor

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    In spite of the questions/hints I've had brought up to me about the metallurgy and hardness/annealing of the Petersen brass, I am thinking about switching to that stuff as I have about 150 virgin cases of it in my "stash" and it is brass that starts out as .284 and doesn't require any extra monkey business to make it into .284, not to mention that I have ALSO heard some good things about it---will have to try it and form my own opinions, I guess. All I really MAY have to do is to get it "adjusted" to my favorite neck tension and maybe run it through a die to make the headspace what I want IF the brass isn't already too short---a bit too long is OK in this case so I can reduce it to my desired headspace.

    Just as an aside, I've arranged to have the FB of my 284 taken from .188 out to probably .230 to accommodate leaving any possible donut that (maybe) develops in place and just seating out away from it while obtaining whatever "jump" I find works best for my gun with (probably) BERGER 180s. I've not heard good things about the ELD-M and ELD-X stuff in various weights, but one never knows until he lets his/her own gun give its opinion. Heck, if a particular bullet turns out to be a LASER in my rifle, I don't care it it is manufactured by a diaper company! The way I shoot, I need every possible break I can get!! I guess I should have never had a buddy do his graphic magic on my McMillan KESTROS-R-------he made it WWWAAAYY prettier than I can shoot it!! o_O
     
    Last edited: Nov 26, 2019
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  12. rardoin

    rardoin Silver $$ Contributor

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    ^^^^ wise move....it will save many hours of brass prep.
     
  13. doninreno

    doninreno cheap old fart Silver $$ Contributor

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    OH, YEAH--THAT is my goal...brass prep isn't exactly my favorite way to spend the most precious commodity I have!
     
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  14. Bc'z

    Bc'z Gold $$ Contributor

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    Well let's see it, I don't know a member here who dosen't appreciate a beautiful rifle!
     
  15. doninreno

    doninreno cheap old fart Silver $$ Contributor

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    OK...this is NOT a good picture, but here it is: IMG_0563A.jpg
     
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  16. Tod Hendricks

    Tod Hendricks Gold $$ Contributor

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    If your trying to remove existing donuts and get more life from your brass, this works very well https://www.mcmaster.com/8803a542 use in a drill on unsized fired cases.
     
  17. Bc'z

    Bc'z Gold $$ Contributor

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    Very nice!!
    Pictures never do the work justice, I can tell your buddy really put some work in on your stock.
     
  18. F Class John

    F Class John NRA Life Member Gold $$ Contributor

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    There what I did at the start of the year when it first was available and I’m loving it and the brass is fantastic. I don’t miss necking up and since I shoot a no-turn neck as well life is awesome. Plus as I said before the donut issue is reduced a ton.
     
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  19. Bindi2

    Bindi2

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    Q for you shooters who are getting the DONUT. Is your case neck length shorter than the chamber neck length. Are you having unexplained pressure spike shots showing flattened primers.
     
  20. Bc'z

    Bc'z Gold $$ Contributor

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    It dawned on me last evening when I was spot checking runout on some ammo I was putting together.
    I'm thinking I don't see the effects of the
    doughnut due to the Wilson bushing die and bushing not sizing the neck all the way to the shoulder.
     
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