Excessive bullet run out. How to remedy?

Discussion in 'Reloading' started by SAPPER26, Dec 7, 2011.

  1. SAPPER26

    SAPPER26 Well-Known Member

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    I am reloading for my 338 Lapua built by Kirby Allen, and finally broke down and bought a concentricity gauge. This was an unwelcome surprise. I see a .004-.006" runout when measuring at the ogive of the loaded round. Here is my process:

    Press is a Lyman T- Mag II turret press
    Full length size with a Forster FL die, ensuring inside of neck is lubed
    Trim to 2.711" on lyman universal trimmer
    Deburr and chamfer with lyman tool
    Prime fed 215M primers with hornady hand priming tool
    Fill with 92.1 gr H1000
    Place Berger 300gr bullet as straight as possible and place round in press with hornady 338 Lapua shell holder
    Using Forster Ultra micrometer seating die
    Push bullet up into die. Once it contacts the seating stem, I gentley tap and rotate the round 4 to 5 times. I then seat the bullet around 1/4 inch then rotate 180 degrees. I do this a couple times until the bullet is completely seated at a COAL 3.870"

    After seated I use a Holland Concentricity gauge to measure. It runs from a few at .001 to the majority at .004" run out at the bullet's ogive.

    So far I am only using new Lapua brass. I haven't gotten to reload the fire formed brass yet. After full length sizing, the brass neck run out is around .001" with a few in the .002 range. I'll neck turn once I start reloading the fire formed cases. I had to adjust the seating stem by drilling out the center so the bullet tips will not contact the stem. It only contacts the ogive now. When I set up the dies, I run the ram up to contact the bottom of the die and tighten the die lock nut hand tight.

    Does anyone have a suggestion on how I should fix this. I know <.001 is the goal. Right now to straighten, I drilled a hole in a 2x4 and "bend" the bullet straight. After this, it's usually around .001" run out. Is this smart? Thanks.
     
  2. Mikecr

    Mikecr Well-Known Member

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    3 contributors here:
    - New brass(not fire formed)
    - Neck thickness variance(unturned)
    - FL sizing(un-fire-forming)

    You will never see <1thou runout without addressing all three.
     

  3. WBY MAG MAN

    WBY MAG MAN Member

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    Oct 15, 2011
    SAPPER26, Mikecr is right on the money. I used to straiten my brass the way you are, never had any problem's through 1000's of round's. I now use the Hornady concentricity gauge that has A built in straitening fixture. With it you are able to get them to .0005 or under with no problem, that was $88.00 of money well spent on A very good reloading tool. I also neck size after fire forming and the next 2-4 reloadings depending on the cartridge before FL sizing. Alot of new brass is 003-006 out, you just have to clean it up one of the way's mentioned above. Good luck and good shooting to ya...
     
  4. Gene

    Gene Well-Known Member

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    Even with loading for BR, it is difficult to achieve .001" total run out consistently. I am satisfied with .000 - .004". The ultimate test is how well it shoots. Sizing dies with a ball expander are a common cause of run out. Remove the expander ball and you might see improvement. Bushing dies are great, and you can select the diameter for best bullet grip. I assume yours is a no turn neck, but turning just slightly - skimming the neck - may show improvement.

    I had one of those tools that bend the neck. Sold it. Problem is that if you use the same sizer die, you will need to bend the neck with every loading, which stresses the brass.
     
  5. RDM416

    RDM416 Well-Known Member

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    Everyone has been giving you very good advice. I went through the same process several years ago when I "discovered" how much runout my loads had. The steps I used to correct are as follows.

    I use a Forster press which floats the case base and die. You can accomplish the same thing by not tightening your die down or using an "o" ring under the die.

    I removed the expander ball.

    I turn necks to get them true.

    You described your seating process which involves rotating the case as you are seating. I do the same and have found it helps quite a bit. You can also try the same when sizing. Some will say this work hardens the case and I have no doubt that it does to some degree. However, with the loads I typically use the problem I see most often is lose primer pockets after 6 or 7 loadings. Never had to discard a case that I could attribute to work hardening. I also anneal my necks after the 1st and 5th loading. I am also full length sizing. No problem with neck sizing, but full length works for me.

    One obvious thing but I will mention it anyway.... make sure you get a good chamfer on the inside of the case neck.

    Following those steps I went from 6 or 7 thou of run out to less than 1 to 2 with an occasional 3 in the mix.
     
  6. Buffalobob

    Buffalobob Writers Guild

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    If you have case neck runout then geometry says you will have bullet runout. I don't bother measuring bullet runout very often. I just check the necks and see if that is good. As was mentioned, how you thread the die in the press and adjust your lock ring makes a lot of difference. Sometimes it takes me three or four tires to get the die set properly.

    You should check your cup in the bullet seater and make sure your VLDs are not seating off of the tip.
     
  7. Bart B

    Bart B Well-Known Member

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    Amen.

    I've tried all sorts of bullet seaters including Wilson hand seating chamber types, a variety of floating collet dies for the press, even a Lyman Tong Tool with a die. All bullets tend to align with the case neck regardless of the type of tool.

    Best solution is to use a full length sizing die without an expander ball and cases with neck wall thickness spread of less than .001". You can lap out the neck of a full length sizing die to 2 or 3 thousandths smaller than a loaded round's neck diameter, but it's easier to just get a bushing die from Redding or RCBS; both use the same bushings.

    Bullet runout's best measured with the front V centered on the case shoulder slope. That's where rimless bottleneck cases center in the chamber when they're fired. Belted cases whose shoulder's set back a couple thousandths in a full length die do the same thing. Best part of this is any out of round of the case and/or chamber at the shoulder-body junction doesn't matter when full length sizing dies are used. Neck only sizing still allows some interference when fired case body diameters get too big. Resting the front part of the case in a V just behind the shoulder ends up with any out of round in the case at that point altering the bullet's real runout.

    30 caliber rifles need no less than 2 to 3 thousandths runout. Bullet's straighten up very well and machine rest tests have proved this is enough. Any straighter's a waste of time. Especially if the loaded round's bullet just barely touches the lands when its chambered and pushed all the way forward by the firing pin like it is when its fired.
     
  8. flashhole

    flashhole Well-Known Member

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    You should be using your runout tool to measure each step/result in the process. This will tell you where you have a problem.

    Measure brass runout before and after sizing. Correct your die adjustment as needed.

    Measure the bullets if you can.

    Measure the fully assembled round.

    I have found the Redding or Forster sliding sleeve seat dies really help minimize runout in the seating step.
     
  9. Coach Hunt

    Coach Hunt Well-Known Member

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    Jun 22, 2009

    Howdy,
    I suggest:
    1. you remove the clip that holds your shell holder on your press. Replace it with the correct size "O" ring. That will help your shell holder float... it seeks its own center in the dies. A SMALL dab of good grease under the shell holder will help as well.
    2. go ahead and shoot your ammo to fire-form. Use your Holland Concentricity gauge to see how "straight" your fire-formed case necks are. If they are straight, your chamber is good. If not, see your gunsmith.
    3. remove the cap and seating stem from your Forster seating die. Test fit your preferred bullet in the stem. If yours is like mine was, it is seating on the tip of the bullet rather than the ogive. A trip to your gunsmith; he can drill that stem out to accept your bullet. I've heard that Forster has addressed this problem recently, but my newest dies must have been missed.
    4. if your stem is good, the next suspect is your press. A good friend used the same press you are using. He had concentricity issues, and fixed them when he "borrowed" my RCBS press. After we measured and checked his turret, it had too much "play" and it was drilled so the dies were about .006" off center. Again, the "floating" shell holder will help this.
    Your other proceedures look good, and my suggestions are exactly what I did to fix the same problem using Berger bullets... in a different caliber. Hope this helps. I wonder if I'll ever get my press back?

    Good shooting.

    Coach
     
  10. Goofycat

    Goofycat Well-Known Member

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    Mag Man: I have never used a concentricity gauge before, so I checked out the current Sinclair catalog and found that they sell the Hornady and their own Sinclair gauge.

    The Sinclair gauge allows the cartridge to rest on two ball bearings, which seems to me a design that might introduce error if the gauge is to be used mainly to check bullet runout. It seems to me that if there are sources of runout problems due to a case not being concentric, that any excessive bullet runout numbers might be due, in fact, to bad cases. I may be wrong here.

    Conversely, the Hornady gauge seems to grab the case at its base, with no contact on the case by ball bearings. This seems to be a better way to find bullet runout because it removes the possibility of getting bad readings at the bullet end of the cartridge if the case is the culprit.

    Therefore....it seems that the Hornady gauge would tend to eliminate error because there is no ball bearing contact with the case. When I read the description of the Hornady gauge, the catalog states,

    "The Hornady Lock-N-Load Ammo Concentricity Tool enables the hand loader to identify the bullet runout of each cartridge, and then eliminate it. Once a loaded round is inserted into the (tool), the dial indicator us used to adjust the cartridge runout to zero..."

    My question: How can runout be eliminated by the gauge? It seems that once runout is present that either the die or bullet (or both) is the source of any runout, and that nothing can be done, short of (1) tossing out the old die and replacing it with one that produces concentric cases, or (2) using a different batch of bullets that don't show excessive runout.

    Maybe I am making things too complicated, but before I plunk out $100 for the Hornady, I sure would like some answers. I haven't called Hornady or Sinclair yet and would rather rely on you guys.
     
  11. Joe King

    Joe King Well-Known Member

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    Goofycat

    The Hornady does it by pushing the bullet strait, it cannot do anything about the cause.

    The Sinclair reads on the body which after fire forming takes on the shape of the chamber, if this is not accurate then you have major problems as your chamber isn't round, the Hornady by holdin the case head is hoping and praying the case head is square and concentric to the case body.

    So one reads from the area that supports the case, the other reads from the part of the case that takes the most abuse, is that a problem? How good is your case prep, tooling and loading techniques, , how good is your gunsmith? Personally I feel that reading with the sinclair and correcting with the Hornady is the way to go.:)
     
  12. Goofycat

    Goofycat Well-Known Member

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    Thanks for the reply, Joe. It seems that if there were a bullet runout problem that was discovered by the Hornady for one cartridge out of a batch of reloads, that the same amount of runout would be present in the remainder of the cartridges in that batch.

    If this is the case, I wouldn't want to have to be faced with altering the runout by having to put all the cartridges in the Hornady to reduce runout.

    That being the case, wouldn't it make more sense to check the first few cases for runout, and if there is runout, see what the cause is, rather than reload a few hundred cases, only to find out belatedly via the Hornady that ALL the cartridges suffer from runout?

    I know that I may not make sense because I haven't read anything on the actual concentricity gauge procedures, nor have I ever used such an instrument, so I ask questions purely from the standpoint of being a complete novice on the subject of concentricity gauges.
     
  13. Mikecr

    Mikecr Well-Known Member

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    The Hornady and H&H type neck benders are popular because they show only a small portion of runout, and then fool you into believing you can easily fix it.
    The Sinclair(with bearings) shows ALL runout, and your cases are NOT straight until measured so on this v-block type of gauge.

    Anyone could try & see this;
    Take a case that measures <1thou TIR on a Hornady and drop it on a Sinclair to see that you still have way more runout.
    Take a case that measures 1thou or less on a Sinclair and drop it on a Hornady, and it won't even register.

    Sinclair sells great tools. But they also sell whatever does.
     
  14. rscott5028

    rscott5028 Well-Known Member

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    I have a Lyman T-Mag press. I was getting a lot of runout as there is flex inherent with the turret design and minimal ability to tweak it.

    I would expect this problem to by magnified due to the large cases you're working with.

    I switched to the Forster co-ax press and have been very pleased ever since.

    I still use the T-Mag for little things like universal decapping, loading pistol cases, etc.

    -- richard