Necking down cases ...

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by dwm, Apr 27, 2003.

  1. dwm

    dwm Well-Known Member

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    I have factory 25-06 REM and 7mm SAUM rifles.

    I was thinking of using 270/30-06 and 300 SAUM brass and necking it down so the case necks end up thicker therefore fit the factory chambers better.

    I have a couple of questions:

    1. Should I start with 270 or 30-06 brass for the 25-06?
    2. Can I just run 270 or 30-06 brass through the full length die and get 25-06 brass?
    3. Can I just run 300 SAUM brass through the 7mm SAUM FL die and end up with 7mm SAUM brass?
    4. How do I determine the actual neck dimmensions of the factory chambers? I will need to know this so I know how far to turn down the newly formed brass.
    5. Do I need to make a chamber cast? Is this hard to do, etc, etc ...
    6. Is there an advantage or disadvantage to having thick brass in a case neck? I know most competition tight neck chambers end up with thin brass on the case necks.
    7. Are there a books I should be reading that discuss all of this? (Might keep me from asking so many questions.)

    As usual, an insight that you guys are willing to share would be greatly appreciated.

    Thanks,

    Doug
     
  2. 4mesh063

    4mesh063 Well-Known Member

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    On the 30 to 7 SAUM at least, I think you will find that the growth will be in length, not in thickness.
     
  3. 4mesh063

    4mesh063 Well-Known Member

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    PS, the 30rsaum is .020 shorter than the 7mm so you better hope it grows!
     
  4. H-BAR

    H-BAR Well-Known Member

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    DWN-Keep in mind that thickening the brass inhibits sealing the chamber properly causing other issues. If you load your rounds into the rifling you will find case neck fit to the chamber irrelevant!!! The only thing about the case neck I worry about is concentricity and keeping them soft by annealing. I have a Ruger in 25-06 with probably the biggest chamber on earth and it shoots fine when loaded into the rifling. In fact it shoots quite amazing groups with 115gr Berger vlds and 55grs Re22. Necking down as I have tried only causes major concentricity problems!!! I also like the Hornady dies for sizing because the collet style holder for the expander ball holds on center better. This holds the neck concentricity to better tolerances than the other dies that I have used. Oh those Bergers were moly coated-don't want to see you have pressure problems if you try them.
     
  5. H-BAR

    H-BAR Well-Known Member

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    oops sorry for the typo DWM on your name. I get unwound when thinking of the neck woes with the 25-06.
     
  6. 6.5 Bandit

    6.5 Bandit Well-Known Member

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    dwm,

    I would agree with H-BAR that you should try loading your rounds close to the lands.. That will more then likely solve your issue..

    H-BAR

    I noticed you are using Hornady dies for 25-06.. I have a set of Hornady dies for that caliber as well but I am having major problems with getting stuck cases in that dang die.. I have been reloading for roughly 12 years if not more and never had a stuck case.. I bought those dies becouse i heard great things about them but no matter what i try, little lube, no lube, alot of lube I even went as far as tearing the die apart and cleaning it after I run 2 through it which is a pain.. But no matter what i try i still get a stuck case.. You have any issues with this? You happen to have any "secrets" on how to stop this or should i be callin Hornady.. I have written them a email about it but havent gotten a responce back..
     
  7. Darryl Cassel

    Darryl Cassel Well-Known Member

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    DWM

    The last time I looked, the 270 brass is 2.540" long and the 25/06 or 30/06 brass is 2.494".
    You will "have to" cut the length back .046" to make it work if you use the 270 or 280 brass for your 25/06. [​IMG]

    Just a thought.
    DC

    [ 05-05-2003: Message edited by: Darryl Cassel ]
     
  8. Brent

    Brent Well-Known Member

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    DWM,
    Alot of guys do just what you are talking about for the same reason.

    If you need to seat them back from the lands this will help as I'm sure you know and is why you're interested in doing so.

    The VLD's, I'm told, will almost always do better up to even .040" "into" the lands, and do poorly away from them.

    The opposite can be true for other forms though. Why? No idea, and haven't heard any either, but I've always wondered.

    The last time I talked to Ken at K&M he told me he was necking something down to 6.5 I think, and he ended up with .038" thick necks.

    Way more than plenty to turn them down to a couple thou total clearance if you wanted to.

    He said he turns the excess off in "one pass" with his turner too, and takes another pass to clean it up, as it's spring loads the cutter from the back cut angle on it that forces the brass tight to the mandrel, which is why his cut to an amazingly consistant thickness.

    You might call him and get his ideas on what to expect with what you have in mind, he'd probably have some good suggestions and is a "real" nice guy too. [​IMG]

    3. Can I just run 300 SAUM brass through the 7mm SAUM FL die and end up with 7mm SAUM brass?
    I'm not sure about the SAUM cases but, with the WSM line, the 7mm is .035" longer so it won't accidentally be chambered in a .270wsm, this is probably the case with the SAUM family too but you could check at shortmags.org where they list the case specs for all of them to be sure. All the wsm's have the same OAL but, the 7mm is longer at the shoulder than the 300 and 270.

    4. How do I determine the actual neck dimmensions of the factory chambers? I will need to know this so I know how far to turn down the newly formed brass.
    Only rely on a chamber cast IMHO, it will tell you everything. If you need any help, I have some pretty good details on doing them I saved from a couple good sources, you might want to read them over.

    Ask away... best to get it straight from someone with experience, and you'll usually find one here or be refered to someone who does. [​IMG]

    Precision Shootings Reloading Manual, it is a pretty good referance on some accurate loading techniques and such, you'd like it.

    Precision Shooting At 1000 Yards is another good book I'd recommend to anyone shooting long range. A wealth of info and very detailed too. [​IMG] Starts off where everything else ends.

    [ 05-05-2003: Message edited by: Brent ]
     
  9. Brent

    Brent Well-Known Member

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    H-Bar,
    almost forgot, my smith said the Hornady dies are real soft, and can even be remachined for wildcats, the others can't. This may be what is causing your excessive stickyness no mater what you do. I use Redding, even though I like the design of Hornadys. I just have had broken Hornady dies and the same problems as you, so I go with Redding now.
     
  10. 4mesh063

    4mesh063 Well-Known Member

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    I use soft dies also but have no problems as Brent mentioned. What kind of lube do you use? I use the water base stuff and my cases actually spring out of the die without being pulled. These are dies I made but I have cold rolled steel dies that nothing sticks to. I get about the same results with Lee and Redding dies as well. I can harden all mine if I want but I see no difference and don't want to waste the time in the furnace to heat treat them. If they're clean and lubed, there's not a reason in the world a case should stick.

    The case Ken Markle necks down is a 416 Rigby. It's shortened a ton also so he is using the same wall for a neck that I do on mine, just farther down. The wall thickness on the body is significant beforehand. Where his neck is the wall is about .028 to 030 and the diameter is around .570. He necks that down to hold a .264 and gains approx .007 from what Brent is saying. I'd agree with that figure and that's not much thickness to gain necking down 300 thou. I would "Borrow" a few pieces of brass from someone before doing this excercise and try it out for yourself because you may make a lot of work for yourself and not gain a enough in your neck thickness when you're done to warrant the time. I'd bet good money you won't see .003 and I'd be surprised it you get .001 on anything other than the 30-06 to 25. If that's enough, go for it. Otherwise, I'd get some spare brass from someone before buying a bag of 100.
     
  11. Brent

    Brent Well-Known Member

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    I know S1 uses Newlon dies, I wonder if he hardens them after or uses them as is too.

    Jim Cartensen said when he presses the sleeve into the FL dies he makes the sleeve is only case hardened first and is about .030" thick, I'm guessing only so it doesn't crush when pressed into the die.

    He said if it were hardened all the way through it would swell the die body instead of slightly collapse the inserts ID. so it would minimally size the case body.

    This is done using your finish chamber reamer, that's the reason for the insert for those that didn't know why one was used.

    I use RCBS lube pad or Hornady Pro Shot spray on, mainly the spray on but the RCBS water soluble stuff is slightly slicker but the Hornady works perfect in my Reddings. Lube the crap out of the first couple and start with a clean die though, it'll be tight to start with until the lube builds up but it don't leave dents in the cases like the RCBS lube does.

    Thanks for clarifying the case he was using there 4mesh. I think the thickness is about .020" tops, even if that, where his necks are getting brass from, even shortening it a whole bunch. The Rigby brass I have is .025" thick 1.0" up from the base and has tapered to .020" thick at 1.4" and is less than .016" at the shoulder. The Rigby case isn't even .030" thick until it's very near the web a 1/2 inch or so up and is almost identical to the Ultra Mag in thickness along the way in every respect.

    Again, Ken may have already done what you are looking at. Barrowing some pieces to experiment with is a good idea. Probably get a handfull on the ground at the range. [​IMG]
     
  12. H-BAR

    H-BAR Well-Known Member

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    6.5 bandit I love the Hornady dies and have had absolutely no problems with them. I use them for my 25 223and my 300ultra. I would send them back and have Hornady repair them. They are really good about customer satisfaction. I have put a couple thousand rounds through both my 223 and 25-06 dies and both are still like new.

    Brent I have one belief in bullets and seating depth and here it goes. I generally believe that all bullets will shoot better loaded into the rifling as long as you tailor the powder charge accordingly. I find that my 25 shot TNTs good loaded at the standard length at 3600fps so when loading into the rifling I decreased the charge to get them to 3600fps and it shot even better.
    So far this has been the same for every load that I have done. About the dies I like the Redding dies also but the design of the Hornady expander is much better. I have to leave the lock nut loose on the expander ball on the Redding dies as well as the RCBS
    dies because they are not centered in the die and will cause concentricity problems. Leaving the nut loose lets the ball float some which is more of a bandaid. The collet design of the Hornady dies is the only one that is on center. Now if you could put a Hornady expander in a Redding die that would be something!!!! Reddings inside finish is beautiful. I do know this also that Hornady warranties their dies for life as long as you have not been neglectful. If I had a bad set I would send them back.
     
  13. H-BAR

    H-BAR Well-Known Member

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    Actually I did have a case stick once in an RCBS die. I was using a case lube that was dispersed in alcohol in a pump bottle. I believe it was Dillon case lube. The problem was that when applying the lube you have to let the alcohol flash off. Once this happens I would spread the lube with my fingers and presto no problems. Sorry I should have remembered this bit of history-Gee I could have been doomed to repeat it!!! Maybe this could be it-If not I would send the dies to Hornady.
     
  14. 4mesh063

    4mesh063 Well-Known Member

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    Brent,

    FWIW, I have one of Kens cases here. It's a short thing for sure. I also have a cut up case so I will give you the #'s. The case I have here is about .023 where his neck is formed from. My necks don't get nearly the .037 thick as his but, mine also don't go to 6.5. The end of his neck on the finished case is about even with my shoulder to body transition so the brass is a bit thicker for him than me where the neck is formed out of.

    His COL is about 1.700" without grabbing the calipers again. Mines 2.150".

    He also talked about going through another process to thin the brass but i'm not sure if he does that now or not. You may actually have a photo of his case if you look back.