what to do with cases with excessive neck run out?

Discussion in 'Reloading' started by cbb, Jan 1, 2012.

  1. cbb

    cbb Member

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    I'm new to detailed hand loading and new to long range equipment. I am loading for a 338 edge- Defensive Edge Canyon (pics pending) and have been following the advice I have read from posts on this site and Shawn Carlock's reloading video.

    New Rem brass that varies wildly before necking up using Redding FL S bushing die. I have been necking up the brass by running the brass just up over the expander, removing the expander, and then sizing the neck with the bushing - expander removed.

    I have tried letting the die float, the expander/stem float, letting everything float, running a good case up and locking the die down, and everything else I read on a detailed post from Kirby Allen on this site. I have measured each step, and my actions have not allowed a neck off at the beginning to really be improved during this process. Only a 0.001 or 0.002 improvement on really off necks. Neck runout varies from 0.001 to 0.013. Only about 1/2 the brass ends up at 0.004 and below.

    1. Is this a normal yield on new brass or do I have a technique problem?
    2. What do you do with all the excessive neck run out cases? Would it be better to just size more brass and end up with all good cases or spend the time and materials to fire form the brass. Would they even be good then?
    3. I have standard RCBS 300 ultra mag die and was considering running the brass through it in the 2 step process before using the redding die to neck up the brass to 0.338 in a 2 step process. Would that be a good idea?

    I tried to do my homework and read many posts on neck run out, but I did not find the answers to these questions.Thanks for your help. I hope to get some quality ammo going to finally shoot the new gun and get some pics of everything to share here!
     
  2. bassin93

    bassin93 Well-Known Member

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    I have the neck bushing tightned up so it sizes the complete neck, well as much as will go into the bushing are you sure you have sized the neck enough or just barely the very end of it and are getting the bad readings from the part that was just expanded but not sized in the bushing? with my chamber, I have to make sure the shell holder cams over on the base of the die or my bolt is stiff to close.
     

  3. Gene

    Gene Well-Known Member

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    Fire all that brass and again check concentricity; your chamber should straighten the necks. Then, remove the expander ball completely and use a bushing that is about .002" under loaded neck diameter. With the die set properly, the bushing should size about 80% of the neck. Expander balls are a common culprit in crooked necks.
     
  4. Mikecr

    Mikecr Well-Known Member

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    While I doubt you read it, or heard it in a video, there are reloading basics related that you should understand:
    The root cause of runout is thickness variance.
    The action that brings it to affect is sizing.
    Your best die is always your chamber.

    If you care to produce ammo with low runout you have to measure and cull cases by thickness variance. Rake offenders into a trash can.
    Then, you need a plan to manage your best brass with minimal sizing.

    New brass and FL sized brass contains all kinds of evil energies. As gene mentioned, it will have to be fireformed to take it to any straightness. Anything you do with it beyond that, will release some runout. And nothing but re-fireforming can straighten it back up..

    So once your brass is straight, try the actions you've learned so far, measuring results of each. Don't deny any truths in it. Just fix this & fix that, until your runout is best you can achieve.
    But your 338RUM is pretty long, and it's highly unlikely that your runout will ever be stellar anyway. It can be 'relatively low'.
    So don't drive yourself to madness with it..
     
  5. Derek M.

    Derek M. Well-Known Member

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    My opinion: Remington brass is the crappiest out there. I won't use it unless I have to.

    Even after firing the brass in your chamber, Remington brass does better with neck turning. Even if your chamber neck is not a tight one.

    I use Federal brass in my 300 RUM but have Remington for my 270 AM.

    Others may disagree but I suggest you start by turning all the necks.
     
  6. bigngreen

    bigngreen Well-Known Member

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    I would contact Shawn Carlock, the internet is a great place to get screwed up and a direct conversation with Shawn would get you on the right track since he built the rifle and knows exactly what steps your going to need to do!!!
     
  7. cbb

    cbb Member

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    Thanks eveyone,
    I was sizing nearly all of the neck to start. I tried sizing to 75% of the neck length but I was not able to decrease my run out. I was measuring in the middle of the area actually sized and not on the ends. I did not check to see if unsized portion will cause a chambering issue. I'll have to go check.

    I was just running the brass up over the expander mandrel without running it up to the bushing. I would remove the expander and then run the brass all the way up to the bushing. Two steps in the same die to get better run out.

    I understand that firing brass in my chamber will straighten it out cases and get my run out much lower if I only use the bushing and not the expander on fired cases. Around .001 from Shawn's video in which he is loading for guns such as mine and made by him. Die was also bought from him so it should match the gun. I will double check the expander and case measurements once I get some fired brass. Thanks

    New to the game, I am afraid of wobbling several rounds down my first custom gun just to get correct cases with .005 to .013 run out because I'm not sure how a case in this category will effect accuracy compared my best new cases and/or once fired cases. I'm afraid they won't be accurate enough to tell me much about the gun or my ability to shoot. Any Info hear would be helpful. Also, a recommendation on fire forming using just primer, powder, and something like cotton.

    I find that the Rem Brass is beat up out of the bag. Dents and some case mouths have flat spots. I was wondering if I ran the brass over a 30 cal expander and then went to the necking up with the 338 die sounds like a good idea. Or, should these cases just be culled?

    What neck variance would you accept and cull when neck turning?

    Thanks for help and please correct my thinking should it be off. My goal is to get the best from new brass so that each shot is a reflection of my shooting and not the equipment. I'm sure I need some work.
    I plan on keeping in touch with Shawn. He has been very helpful and answers all of my questions. I asked these questions here on a day his shop was presumed closed - Holiday weekend. I will be asking Shawn these same questions. I am also trying educate myself enough to ask intelligent questions and not being too big of pain to anyone. Casey
     
    Last edited: Jan 2, 2012
  8. Frank7mm

    Frank7mm Well-Known Member

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    One thing to look at is a expander mandrel die from sinclair. Got one awhile back and works great. You wouldn't think the expander mandrel could help all that much opposed to a normal die expander but it works. I had runout when necking 7 WSM up to 338 until I bought one with a 30 and 338 mandrel. Just my 2 cents.
     
  9. TikkaShooters

    TikkaShooters Official LRH Sponsor

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    With proper neck turning all your necks will have uniform thickness. I prefer .015 neck thickness and then neck size with .002 tension.

    If you cull cases, do so after you have all the external dimensions uniform including primer pockets and flash holes. Then measure weight and segment your brass by weight.

    Neck turning is necessary for maximum bullet concentricity and is even more important when necking up or down brass.
     
  10. Mikecr

    Mikecr Well-Known Member

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    Neck turning only gets a small portion of the case uniform. The rest of that case length is still not uniform, and this combined with cycling of it(sizing/firing), allows cases to end up bananas as measured on a runout gage.
    Now if you didn't size all that length, fireforming would put it fairley straight where it would remain so. But I suspect you will have to FL size those cases eventually and from then onward.
    This is why I think you should measure thickness variance(as seen in the necks), and keep only cases under 1thou in 360deg variance. You need a ball mic with a stop for this.
    These would be cases to further prep, and neck turn.

    I damn sure wouldn't generalize capacity by Remington brass weight..
    After prepped, fully fireformed, & before any sizing, just measure it's H20 capacity and again cull offenders.
    I imagine Rem brass is dirt cheap and would consider it disposable. And matched brass is gold regardless of brand, so you've got nothing to lose really.

    I agree with frank7mm about the Sinclair expander die system. It is by far the best expansion short of fireforming.
     
  11. cbb

    cbb Member

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    Thanks for your help. I have a better understanding of the process now.
     
  12. BountyHunter

    BountyHunter Writers Guild

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    Fireforming will get the case uniform IF it has equal dimensions in wall thickness. If not, it will be banana shaped and nothing can fix that.

    Get rid of the expanding mandrel in the FL die and go to a straight decapping stem and runout will cease IF it is die related.

    All brass is beat to hell when it comes out of a bag. Use the expanding mandrel to take the dents out and resize down to the dimension you need.

    The use of the Sinclair or K&M expanding mandrels is all you need to maintain neck expansions in lieu of the die expanding mandrels.

    Contrary to some, NS is not the wonderful panacea as touted. IMO it is a poor excuse for not getting rid of the expanding mandrel and will lead to work hardening of the brass and vast variances in the brass as the brass grows until you get the dreaded bolt "click" and hard opening. Worse yet, you get hard chambering on the hunt. By then, too late, the brass has work hardened and you will have trouble from then on maintaining uniformity. NS only results in unreliable functioning and and wide variance in brass. Very few people actually measure cases with an accurate blade mike to actually measure brass variance. Try it some time and watch the brass grow dimensionally on NS only brass vs uniform FL sized brass with a dimensionally correct FL die.
     
  13. moombaskier

    moombaskier Well-Known Member

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    I have had excellent results when sizing to cycle the case up into the die, then rotate the case 90 degrees and repeat. I've seen this simple process work wonders when sizing. When I seat the bullets I rotate the case approximately 90 degrees 3-5 times while seating and that too helps to obtain low runout. You definately want to at least take the high side off the necks too.
     
  14. cbb

    cbb Member

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    Update, I ran less beat up new 300 Rem ultra mag brass through a standard RCBS die just over the sizing ball to make it more uniform 30 cal opening. Neck run out was typically 0.002, surprising me. I then ran it over the redding die mandrel to neck up to .338 size. It has a longer sizing mandrel compared to the RCBS (0.375 vs. .053 of visualized brass contact area.) The force needed on the handle of the press to neck up seemed more consistent having made the 30 cal opening more consistent before necking up in size. I think I will do this again if for no other reason than it made me feel warmer inside. It may also have helped run out, but I was also using brass that was in better shape.

    I picked up run out when necking up. I tried rotating, I tried running the mandrel up higher in the die, I floated the stem, I floated the die, I floated both, etc. I was unable to improve my run out in this step - .001 to .008. (But, much better than before with rougher brass)

    Due to the force involved in necking up, I could have picked up run out in several places. Case just a little out of line in shell holder, shell holder not exactly square to ram causing some cant of the case, ram of press wobble as I push brass up, base of brass not square to rest of case - allowing the stem to float should help in these areas as I understand things. It may also be due to neck wall thickness variances causing the neck to stretch out a little more on one side than another. Maybe the Redding mandrel is not as good as the Sinclair. In my case, I'm guessing it was mostly the the brass and how and where it wanted to stretch- thickness related in the neck and possibly other areas of the case to a lesser extent as the case body of this new brass is not touching the die body when the neck is going over the sizing mandrel.

    Anyways, I ended up with 53% of my brass .004 and under, 80% under .006, and 100% under .008. Still not sure if that is good or bad yield on new rem brass when necking up. I am going to finish loading some of my best cases, try to correct any bullet run out with a Hornady concentricity gauge, and shoot a few rounds this weekend!

    Once again, please point out any misunderstandings in my thinking. I realize that I may not have it all straight and welcome your thoughts. Thanks for you help and your time. Casey