Headspace gauge/resizing die question

Discussion in 'Reloading' started by cornchuck, Feb 11, 2011.

  1. cornchuck

    cornchuck Well-Known Member

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    I have been reloading my own ammo for about 6 years now. I was taught that when setting up the full length sizing die bring the ram up with shell holder to full stroke. Also having a fired cartridge of that caliber I am reloading in the shell holder, thread the die down until it just kisses the shell. Lock down the die.

    I purchased some Precision Mics from RCBS that contains the headspace gauge. I never really paid to much attention to this gauges until recently when I was reading how to set up resizing dies and I started to play with them.

    I was reloading for my 243 win when I got to thinking about the resizing die. So I took a look at what was going on. According to the instructions with the gauge, a 243 gauge is set at zero for a measurment of 1.6300 inches. When I put a fired unprimed cartridge in the gauge it says that it is between .001 to .0025 under the minimum length. When I run it through the resizing die, the cartridge grows. I measured the case before and after the die and it grows about .002 to .003 inches in length.

    I thought the shoulder would be pushed back. But the case gets longer.

    Is there something wrong with what I am doing? Do I need to just start over with the resizing die?

    Jason
     
  2. 7 loader

    7 loader Well-Known Member

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    The instructions you gave sound more like a bullet seater not a FL sizer. A FL sizer should be set to touch the die and even a 1/4 turn more in some instances. The shoulder is not being touched and the expander is catching the inside neck therefore pulling the brass longer. What dies are you using?
     

  3. cornchuck

    cornchuck Well-Known Member

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    7 loader, I am using Lyman resizing dies. After you said the die is suppose to touch the shell holder, I got to thinking if it is touching. I will have to check that out. Aren't full length dies suppose to push the shoulder back too?

    Jason
     
  4. cornchuck

    cornchuck Well-Known Member

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    7 loader, I have another question. You said the expander might be catching the inside of the neck which could be make the case longer. Should I use more lube in the necks. I do use Hornady's aerosol case lube.

    Jason
     
  5. nicholst55

    nicholst55 Member

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    Here is Sinclair's take on the subject: How to set up a full length sizing die.

    Now, bear i n mind that Sinclair wants to sell you all their neat and wonderful products; still, their method works.

    IMHO, setting the sizing die so that it contacts the shell holder may or may not be the correct thing to do for any given rifle. When you switch rifles, brass, or shell holders, you may or may not need to readjust your FL sizing die.
     
  6. Gene

    Gene Well-Known Member

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    Pulling a neck over a unlubricated expander ball will lengthen the brass. Keep your brass trimmed back about .010" under SAMMI specs. And do not seat bullets out so far that they are jammed into the bore.

    The instructions for F/L sizing are correct. After sizing, try to chamber a unloaded, empty case in your rifle. If the bolt goes down hard, it means the shoulder is too tight a fit in the chamber. Take that case out, re-lube the entire case and inside the neck, turn your sizer die down another quarter turn, size the case and try it again. When turning the bolt down, you should feel just very slight resistance. At that point, the headspace is perfect, and you can now full length size all your brass at that setting. If still too tight, turn it down another quarter until you have a snug fit. If the bolt just flops down, you have gone too far and increased headspace to a point of danger. Throw that case away, raise the die slightly and try again.
     
  7. 338winmag

    338winmag Well-Known Member

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    Skip that touchy-feely-turney approach.

    "IMHO, setting the sizing die so that it contacts the shell holder may or may not be the correct thing to do for any given rifle."

    Your honest opinion is 100% perfect. "May or may not" is not only the best answer, it is the RIGHT answer. My first reloading die purchase and 4-5 reloads later could have cost me some ill will. I followed exactly per manufacturer instructions which is wrong and had close call with incipient head separation. The Sinclair page is very good but being an engineer, I hate it when someone says "go by feel"! For many people that approach is so relative and most cannot feel .001 - .002. and even if they do, every single rifle is totally unique so one has to not only be able to feel but also feel for each rifle's characteristics. I am not saying some reloaders don't have some success doing this by feel or by manufacturer's instructions, but I have my paycheck betting the large vast amount of reloaders doing it that way and think they are just fine aren't in that .001 - .002 headspace range and those are the numbers to really shoot for (period).

    There are a good number of tools that one can appreciate in your concern. Here are mine.

    IMHO this tool cannot be beat but it does cost a few more dollars than some tools but it is so so worth it. Larry Willis's Digital Headspace Gauge.
    Innovative Technologies - Reloading Equipment I researched over and over and this tool just works, and works too good to now be without it.

    Once you understand how to use the tool, (3 -4 shells possibly) you will question how anyone in this world can go by the "feel approach" or the "turn 1/4 approach". Not trying to be disrespectful to all but you will see that turning the die down even 1/16 - 1/24 of a turn (depending on die) makes the difference between .001 and .005.

    This tool also works just TOO PERFECTLY for bullet seating depth in conjunction with Hornady's L&L OAL gauge and comparator. There are some considerations using this tool and Hornady's custom modified case in your OAL measurement but using this tool and Digital Headspace Gauge I think is super easy, fast and very accurate. (Having seen the homemade modified case approach fail because some bullets move when removing this case - Hornady's product or similar products are much better and much more accurate)

    P.S. - A member on here - WOODS (he is in my opinion an experienced expert) - has different tool(s) to perform OAL and bullet seating and is very good too.
    Call Larry Willis and talk to him. It will be 10 minutes of your time extremely well spent. (and no I do not work or personally know Larry except for this product sale)

    Please guys - some of your instructions are setting people up for incipient head separation issues.

    Again - Skip that touchy-feely-turney approach.
     
    Last edited: Feb 12, 2011
  8. 7 loader

    7 loader Well-Known Member

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    Yes they are the FL die is for returning th rbrass to its factory specs.
     
  9. 7 loader

    7 loader Well-Known Member

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    You are right but I tend to follow the directions From the people that designed the equipment first. In my opinion all new comers need no less than 3 books that are well read and allways back up any info from the internet with a book. Head space guages will not tell you the size of your chamber afterall all guns are not the same. But these are wonderful tools that will be money well spent. And also incipient separations can be caused by more than how you set your die take pressure for one.
     
  10. 338winmag

    338winmag Well-Known Member

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    Thanks for the reply 7 Loader. ;)

    Been down this road too many times but will state it once more.

    Regarding --> "but I tend to follow the directions From the people that designed the equipment first".

    This is where I have a problem. I have actually spoken with two manufacturers regarding this exact topic. they will do a slight side-step and backstep in the discussion.

    As I was told, die manufacturers do not specify how many times a case can or should be reloaded. Their instructions pertain to "resizing the brass" and not "resizing the brass, 1, 2, 3, 4, or more times". They state "so much of a turn" in correlation to the number of threads per inch per turn and give that as a starting point.

    If one resizes over and over and does not properly resize headspace to shoulder for minimum headspace, the firing and resizing will severely over-work the brass so much that a wall weakness (thinning) will occur in the case just above the head. Properly resizing from the start will minimize this occurence and safely extend the case life.

    Contrary to popular belief that keeps on getting passed on to others, it is not a "over normal pressure" or "high pressure" issue as some people state, but rather just the normal everyday pressure affecting a "now weak spot on the brass". If one never resized the brass case and could get away with it still chambering, a thinning of the wall would never take place before the brass was totally useless.

    Continuous firing and "improper resizing" causes the case (usually belted cases) to become defective case and this is what causes incipient headspace separation and not excessive pressure on a healthy case.

    Excessive pressure causes other issues but it is not the reason for incipient headspace separation though it can complete the incipient headspace separation cycle.

    Again incipient headspace separation is from "firing and ""incorrect over headspace resizing"" causing a thinning of the cartridge wall at its weakess point.

    Some deep research will prove this to be true. I will stand firmly behind my statement for the safety of friends, fellow reloaders and family for reloading.
    Skip that touchy-feely-turney approach.

    Nothing personal here, really, but how many will do the same when just stating, "oh just follow the manufacturer's book and give it a 1/4 turn or so untill it feels just right." We are talking about thousands of an inch here.


    Thanks All
    I have given my thoughts and will move on.
     
    Last edited: Feb 12, 2011
  11. cornchuck

    cornchuck Well-Known Member

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    Thank you for all of the replies. I thought maybe something was not right. I will just have to go and adjust my dies the way it suppose to be. Now I know that there is a certain way of doing it and not just by what the manufactures say.

    Thanks again

    Jason

    Ps... If anyone has any more thoughts on this subject, keep them coming.
     
  12. 7 loader

    7 loader Well-Known Member

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    Ok. I said start with the manu's directions and move from there. I care about my fellow loaders saftey and that is why I say follow the book. I also do not indirectly attack someone's experiences in loading and then claim "this is not a personal attack". I do appreciate your impute but I don't mix words. Any loader with experience would give their advice and say go and research my freind what works for me may not work for you. A very good friend of mine followed another persons advice with no research now is scared for life. I am a caring careful loader. And would hate to see anybody get hurt.
     
  13. Gene

    Gene Well-Known Member

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    Comments by 338mag are proper. But for most inexperienced reloaders, the method I suggested is the easiest to learn. Many do not have special tools to determine headspace. I have several precision MIC's, and don't like them. I am using a Redding Instant Indicator for all my competition brass now, and it is by far a superior tool. I can lower the shoulder by .0005" if wanted.
     
  14. bigngreen

    bigngreen Well-Known Member

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    The directions with the dies assume everyone else in the process has also done their job but this is rarely the case. If your gun is sloppily headspaced, but in spec, at the factory you will find yourself over or under sizing and this is NOT the die makers problem! I've re head spaced a couple rifles recently that I had to size with the die up of the shell holder or grind the bottom of the die and after fixing the rifle I set up the dies and found that I get a FL resize with a .0015 shoulder bump with shell holder contact and a slight cam over. Brass life and consistency improved dramatically. This is the nice thing about doing your own work or having quality work done for you, the tolerance stacking is kept to a minimum!!!