Newbie Needs Help Sizing!

Discussion in 'Reloading' started by gunaddict62791, Dec 15, 2010.

  1. gunaddict62791

    gunaddict62791 Member

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    Just getting into reloading and having a slight dilemma finding information i need. For reloading my .308 i have a set of RCBS fl dies, and set them to bump the shoulder back .001 - .002 using the hornady lock-n-load headspace gauge. There are a few questions that i still need addressed.

    1) When do i need to reset the die to achieve the same .001 - .002 shoulder set back? [ between every case, between every reload secession ie. after once fired...twice fired...three times fired... ect. , when i switch brass brand ,ever...?]

    2) How should i set my fl die to handle new unfired brass? I'm guessing that how it is set to handle once fired fire formed brass from my chamber will not even size brand new brass... Once it is fired out of my chamber can i then go back to the original setting i had for once fired brass to bump the shoulder as long as it is the same kind?

    3) If i bought once fired brass fired out of a different chamber how should i set my die to handle this?

    If possible explain how you do it... not how the instructions that come with the die tells you how to as many suggest that all these instructions are good for is toilet paper:D. I am looking for minimal brass stress. Any information would be a great help. Thanks
     
  2. Kevin Thomas

    Kevin Thomas Well-Known Member

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    If you've got a set of bump gages such as the Lock-n-load from Hornady, let that tell you when you need to adjust. You should be able to set the die once, lock the ring and not worry about setting it again. However, that assumes (never a good idea) a whole lot. The exact same cases, the same brand (at the very least), the same amount of lube, correctly applied for each reloading, reasonably mild loads that aren't stressing anything too badly, and that the brass has only been fired in your rifle. More here, but you get the idea. I would check it with the gage and just assume that you'll have to do some adjustment. If the gage says no, you're ahead of the curve. If it says to adjust, adjust as needed.

    New brass should be resized, but the primary reason for doing so is to round out potentially dented case mouths (yeah, it happens) and to even up neck tension throughout a virgin lot of cases. It shouldn't result in any movement of the shoulder or changes in the HS dimensions. For this initial sizing, I'd probably back the die off a half turn or so, and make sure you're not bumping the should. You probably won't be able to anyway, but why take the chance?

    For once fired brass, I'd consider purchasing a separate die; a small base die. These set the brass back much closer to their unfired dimensions than do standard full length dies, which may be useful if using brass from dubious sources. Since you're loading 308s, if you wind up using military brass, these may be a necessity anyway. Good for resizing brass that's been used in M14s or military bolt guns, but even with these, brass coming from MGs (M60s, M240s, etc) aren't worth the effort.

    Hope that helps, and welcome to the hobby!
     
  3. RockyMtnMT

    RockyMtnMT Official LRH Sponsor

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    I load to hunt, so I don't know if my way will help you or not.

    I always full length size. The .308 should not take much of a "cam over" on the ram when all the way up. A slight cam over will be enough. I run brand new brass the same as fired. This will get the neck correct to accept the bullet. I run different brands of brass the same always. But I try not to mix brands of brass.

    In other words, once the sizing die is set, I do not touch it. The seating die is the one that gets adjusted.

    Steve
     
  4. BountyHunter

    BountyHunter Well-Known Member

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    Caution, setting the dies to "cam over" may or may not be a good idea. it is going to be totally dependent on your dies and where the shoulder is.

    The "cam over" is per the instructions to ensure that you set the shoulder back, normally waaay back which is not good to long brass life, but it will chamber.

    BH
     
  5. Reloader222

    Reloader222 Well-Known Member

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    You must read the instructions of the dies. Some brands must be over-cammed and others not. Usually RCBS's instruction is to over-cam. It all depend on whether it is brass from another rifle or not. Should it be from another rifle and the empty case closes difficultly when you camber it in your rifle, it is better to bump the shoulder a little bit back.
     
  6. Innovative

    Innovative Well-Known Member

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    gunaddict62791 ........

    If you want your handloads to fit your rifle perfectly. You need to compare the size of your handloads "at the shoulder" to one of YOUR fired cases. It doesn't mater if your fired case was fired one time or ten times, but it must have been fired in your rifle.

    Remember: Your fired case is like a casting of your particular chamber. I always recommend FL resizing - if you do it accurately. This involves measuring and comparing - not guesswork. Your brass will last much longer, your case run-out will be reduced, your handloads will always chamber, and your accuracy should improve.

    I use the Digital Headspace Gauge because it works on ALL different calibers, and you get consistent readings.
     
  7. boomtube

    boomtube Well-Known Member

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    gunaddict62791 your questions are valid and some of the reasons for confusion are posted here. Fact is, Mr. Willis is fully correct about using a gage to get it right.

    But first you should know that "cam over" applies only to the press, not the dies or cartridge. All it means is that the lever and toggle has pushed the ram fully up and started back down a tad, "cammed over". It has no more meaning than for a press that comes to a full stop at top dead center and moves no further. Where the die is in that movement is the critical part and that is up to the user.

    Now, for very good accuracy, good case life and slick chambering, it's commonly considered to be better to FL size for sporting rifles each time. But, it IS best done with the minimum amount of working the case shoulder. A case shoulder gage (such as Mr. Willis sells - Goggle "Innovative Technologies", or the Hornady, Sinclair or RCBS tools) lets us actually measure where the shoulder of a fired case is. It CANNOT be done by eye or even feel, we must have a gage that measures to the thousant the distance from the case head to the shoulder. (Exactly where we measure to on a shoulder is irrelivant, the entire shoulder is equally usable for comparitive measuring! :) )

    Somber instructions to adjust a sizer to touch the shell holder plus another magic 1/4 turn, etc, is silly. That presumes every press has the same amount of spring and slack in the lever linkages, every die has exactly the same inside diameter and internal length and every case will give exactly the same resistance to sizing. That's obviously not true. We must find what our combination actually requires, not follow some specific method that only gets most people in the right ball park.

    So, how much to "set shoulders back"? Well, why set then back at all? A fired case has expanded to the fit the chamber and sprung back a tad already, it will easily re-chamber just as it is.

    Therefore, why not simply set the FL sized shoulder back so the longest sized case is no longer than it was to start with? That will be fine, let the shorter ones fall where they will. I said adjust for the "longest" fired and resized case because individuals WILL vary some 2-3 thou both after firing and after sizing; it's a fact of life that cases are NOT totally uniform in how they springback! Even seemingly trivial things as how hard you press on the lever, how long you hold the pressure, and how much of what type of case lube you use will make small sizing differences too!

    Some people call what I'm describing "partial FL sizing" but it's much more than that. Partial is ian ndefinate word, it only means something less that maximum. What I'm talking about might better be called "custom FL sizing", doing it precisely to match YOUR chamber.

    Jamming a case into a FL die as far as it will go isn't very helpful for accuracy or case life. Fully restoring cases to original SAAMI dimensions only assures they will be made smaller than needed. The ONLY reason to do that would be so you could fire your reloads in every rirle ever made for that cartridge but that's NOT what you are going to do, is it?

    Custom FL sized cases will NOT stretch very much no matter how hot the load is so custom FL sized cases won't seperate at the head. Sure, the necks get worked a lot with FL does but ditto with neck dies. So, neck splits are what will kill most of your cases and, on average, it won't make a bit of difference if you neck size them or neck size them.

    Once your FL sizer is set, the ONLY reason to tweak it is to accomidate differences in hardness and springback; the brand, new, old, fired, unfired really isn't the issue. A gaging tool makes it pretty easy to adjust for a custom fit and you will soon learn how much change you need to make to see a difference. Die body threads are coarse at 14 turns per inch (about 72 thou per turn) so they require VERY SMALL changes during adjustment to avoid going too far.

    The full head space range for most bottleneck cartridges is around 6-7 thou. The oft seen suggestion to make "small adjustments of 1/4 turn" actually moves the die about 18 thou, some three times the full min to max range! Remember that 1 thou of change occurs with every 1/72th turn, so small changes mean exactly that, not the massive changes that usually get mentioned as "small"!

    Have fun!
     
    Last edited: Dec 15, 2010
  8. RockyMtnMT

    RockyMtnMT Official LRH Sponsor

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    Great post.

    My post was too simplistic. You are spot on. Dies and chambers are all different. I tend to error on the side of consistency and do not worry much about the life of the brass.

    Steve
     
  9. JeffP40

    JeffP40 Well-Known Member

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    I keep it as simple as possible. I don't use any guage, I use the rifles chamber, just as I use the throat of each rifle to seat the bullets. Full length ensures the brass will fit every chamber out there, but it means nothing to your chamber. I have two 270s, one a fwt,, the other a Colt Light. The Colt and its' brother, my 7mag., both have very minimal chamber specs. I have to set the sizing dies for each a lot deeper than for the Win. which has a typical factory chamber. (It's not a "bad" chamber, just a result of mass-production. with every rifle, I set the die down only enough to go just past bolt resistance. This tells me that I am ensuring good chambering, but not working the brass too much. My brass does not stretch much at all, and even the once-fired stuff I use will chamber fine. Basically, you want to set it up so you are fire-forming each piece of brass to that chamber, and not screwing it up by later sizing too much. The "cam-over" they mention is for the beginner to ensure the brass will fit everything. Almost like shooting factory ammo every time. I even do this with the belted 7mag. There is virtually no difference with them, as the belt was originally developed to give the long tapered cases of the Cordite era some way to acheive proper headspace. When you have a good shoulder, I believe it is best to use it for proper fit. The only reason I can see to bump the shoulder is if you are getting resistance from the bolt. If once-fired brass from a different rifle will chamber fine in yours, then just lightly size it and shoot it. It will then be a good fit for your chamber. If it will not fit without resistance, back out your die and slowly turn it down until you get the right fit. You should be good to go. I hope this helps, it works for me. Jeff.
     
  10. Innovative

    Innovative Well-Known Member

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    Jeff .....

    Sometimes keeping it too simple causes problems. If you wait for your handloads get tight before bumping the shoulder, your accuracy will suffer. We always try to make concentric handloads, and if they're jammed into a chamber tight - they become anything but concentric.

    Another reason to "measurie things" is to determine exactly what is causing your handloads to be tight. A tight fit is not always caused by the shoulder. Quite often shooters will bump the shoulder back, when the real problem is case width. When the shoulder gets bumped back too many times, it stretches the case and causes headspace separation. This is especially common with belted calibers.
     
  11. JeffP40

    JeffP40 Well-Known Member

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    I didn't mean to imply that I wait until I get a tight bolt. I sizer the same every time. I never change the sizer die adjustment after I find the right spot, so all of the brass fits the same every loading. I know that using a neck die requires a full length sqeeze every so often tho.
     
  12. Innovative

    Innovative Well-Known Member

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    Jeff ........

    If neck sizing requires a full length squeeze every so often, it's because your brass is not staying the same size. That's why benchrest shooters use FL dies. Most benchrest shooters use expensive custom built FL dies designed for their particular rifle.

    Measuring handloads (compared to your chamber) reveals a lot of surprising information. It's the best way to make your handloads fit reliably, it extends the life of your brass, and it reduces case run-out. Case head separations can be totally eliminated - if you can measure and set your FL die height accurately.