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Thread: Neck sizing?

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    Member RMiller's Avatar
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    Default Neck sizing?

    I have a 300 WSM that I have only neck sized the cases on.

    Will I most likely need to full length resize these at some time?

    Or should I be able to get my 6-8 loadings by neck sizing?
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    As long as they chamber fairly easily there would be no reason to full length resize them.
    Tennessee

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    Default neck sizing

    At some point [depending on load - pressure] it will become necessary to use a full length die to bump the shoulder back. You will know its time, when they start chambering tight. When bumping the shoulder, only take them back a little bit. When you close the bolt you want just a little tension at the bottom of the bolt throw for optimum accuracy.

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    Default neck-sizing

    "When you close the bolt you want just a little tension at the bottom of the bolt throw for optimum accuracy."

    This is a theory I have not encountered before. The more I look at this sentence, the more I need to sit with a toddy and stare at the wall.

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    Bumping back the shoulder is vary common. It usually requires the moving back the shoulder by .001 to .003. This can be done in most neck sizeing dies. The reason you don't want to go beyond .003 is due to the fact that you don't want to increase the headspace. Leads to shorter case life. That's why you are looking for the feel at the bolt closing.

    This is a common procedure for wildcatters changing case shape.

    Obviously the next question would be? How to set the amount of shoulder set back. The way I do it, I take a cutoff end of the barrel, about 1.5", chuck it in the lathe chuck and run the finish reamer in to the stub, cut a part of a new chamber. Then I face off both ends of the stub. You run a case in and measure. Now you use die shims to set the die. You keep checking until you get it right.
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    Quote Originally Posted by thesteeleboy View Post
    At some point [depending on load - pressure] it will become necessary to use a full length die to bump the shoulder back. You will know its time, when they start chambering tight. When bumping the shoulder, only take them back a little bit. When you close the bolt you want just a little tension at the bottom of the bolt throw for optimum accuracy.
    It does make sense to keep the cases headspaced for the rifle.
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  7. #7

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    I have heard a technique in neck sizing where you only resize about 3/4 or so of the neck, leaving a small donought around the shoulder. In this particular case the guy was talking about neck sizing 300 WSM. Anyone else use this technique? Comments?

    Also he showed (sold) me a floating style inside neck sizer that allows for a straighter neck, diminishing run out. I thought that was pretty cool.

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    The simple way to keep TIR low is to leave the die, floating rather than tight in the press.
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    I have never had to bump in all the years I have necksized 6.5x55, 308, 6mmBR etc

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    We are talking about the headspace dimension here. The biggest advantage of hand made ammo is having ammo that is perfectly fitted to your rifle's chamber.

    Neck sizing with a neck sizing die and partial full length resizing are two different things. A neck sizing die will not size the base. (unless the chamber allowed the brass to expand beyond maximum chamber dimensions.) A F/L die will size the base but can be adjusted to size only a portion of the neck. Mostly everybody knows this.

    A neck sizing die, like an F/L die, will bump the shoulder unless backed off slightly, about 1/4 turn. The best way to bump the shoulder is to use a body die which will not size the neck but will push the shoulder back. When this die is adjusted to allow tight bolt closure and not bump the shoulder, we can then switch to a .002" shorter shell holder and have precise control of the amount of shoulder set back. These shorter shell holders are are available in .002" increments and offer a range to suit any need. I've used this system to load many rounds of precision ammo for competitive long range shooters. When I order dies I get a three die set, a neck sizing die, (may be a bushing neck sizer for precision calibers) a body die and a seater die (which may be a micrometer adjusted die).

    A note of specific interest may be that the body die is the only die which can be used to size loaded ammo. It isn't recommended by the maker but it can be used. Also when loading for an auto-loader, I use a small base body die, which is just an additional die to a normal two die set . That way I don't use SB dies for loading ammo for bolt actions AND this SB body can be used to "fix' loaded ammo to chamber in another gun or used to smooth out crimp wrinkles and shoulder crumples.

    Precision loaders use a neck bushing die with sliding sleeve and the bushing cut to fit their exact chamber and brass that sizes only the neck and a competition, micrometer adjusted seater die. They then add a custom body/shoulder bumper die and custom shell holder. They load to the max and get about forty rounds from each piece of brass.

    Headspace for most calibers (shoulder headspacers) has a .006" window. The "Go" and "No-Go" gages are only .006" difference in length. (headspace dimension) Many chambers are as much as .012" larger than what is the SAAMI factory chamber minimum dimension to the shoulder. If you have one of those chambers, a one size or one adjustment does not fit all when sizing ammo. The dies are made to much more exacting standards than the barrel chambers. You must find the dies and die adjustments that best fit your rifles chamber. That's what it's about, it is not so much about getting the maximum life from your brass, though that is an issue today. The best way to preserve the life of the brass is to reduce your loads. Belted magnum case life is another story, and needs better this neck sizing attention more than the others.

    When I buy a new (or used) rifle, the quickest way for that rifle to go back on the rack is if the chamber is ill shaped or over sized. I know it will be nothing but trouble and to this day, after well over one thousand rilfes in my hands that I've made ammo for, I have never made such a chamber shoot with precision. I have some that are long in the headspace but I still load ammo to fit and they are ok but without this custom fitted ammo they wouldn't shoot nor would brass last more than a couple of frings.
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    Quote Originally Posted by RMiller View Post
    I have a 300 WSM that I have only neck sized the cases on.

    Will I most likely need to full length resize these at some time?

    Or should I be able to get my 6-8 loadings by neck sizing?
    You will probably get ten loadings from the very strong WSM case with just neck sizing.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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    Smile question

    When I commented that I needed to full length size my wsm, at least one person told me told me that this was not possible. They said "it ejected fine right? Then it can be necksized only and shouldnt be tight." All I know is that without full length sizing on my Tikka my 300wsm is very difficult to chamber. It appears to be tight around the base. Anyone know why a case would eject fine and then be really difficult/impossible to chamber? This is what keeps me from neck resizing though.
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    Quote Originally Posted by Sollybug View Post
    When I commented that I needed to full length size my wsm, at least one person told me told me that this was not possible. They said "it ejected fine right? Then it can be necksized only and shouldnt be tight." All I know is that without full length sizing on my Tikka my 300wsm is very difficult to chamber. It appears to be tight around the base. Anyone know why a case would eject fine and then be really difficult/impossible to chamber? This is what keeps me from neck resizing though.

    If it ejects fine will it chamber the fired case fine? If it chamberes a fired case fine it will also chamber a neck sized case fine.

    If a fired case chambers fine but a loaded case does not in my experience it is from crimoing or to much powder bulging the case.

    I have some nickle cases that I have to full length size. They eject fine but are tough to chamber.
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  14. #14

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    I just talked with a guy this morning where I'm buying my rifle and loading supplies. He always full length sizes and he leaves a little *donought* around the base of the neck by the shoulder so the cartridge chambers snuggly and centered. He also trims his cases each time he reloads them because he is an accuracy stickler. He showed me a few other techniques too. He claims he shot a one hole 4 shot group at 100 yds once. He didn't shoot the fifth shot because he didn't want to blow it so he could bring it in and show the guys at work. His 300 WSM is his most accurate and favorite rifle. I'm going to follow his techniques because they seem to work real well for him. It's a lot of work trimming for each reload etc., but once I have a load worked up I'll probably shoot less than 100 rounds a year in it.

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    Member RMiller's Avatar
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    The lee hand held case trimmers make trimming easy.
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    I already have a motorized RCBS, is the Lee easier?

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    Quote Originally Posted by MontanaRifleman View Post
    I just talked with a guy this morning where I'm buying my rifle and loading supplies. He always full length sizes and he leaves a little *donought* around the base of the neck by the shoulder so the cartridge chambers snuggly and centered. He also trims his cases each time he reloads them because he is an accuracy stickler. He showed me a few other techniques too. He claims he shot a one hole 4 shot group at 100 yds once. He didn't shoot the fifth shot because he didn't want to blow it so he could bring it in and show the guys at work. His 300 WSM is his most accurate and favorite rifle. I'm going to follow his techniques because they seem to work real well for him. It's a lot of work trimming for each reload etc., but once I have a load worked up I'll probably shoot less than 100 rounds a year in it.
    He is not F/L sizing if he leaves this little donut around the base of the neck, he is partial resizing with either a neck die or a F/L die. The F/L die resizes the body IF if the die contacts the shell holder, it will also fully resize the whole neck. If you back off the F/L or neck die it will leave the base of the neck with this little donut, especially if the chamber is a little over sized at the neck as it would seem his is.

    I've shot dozens of one hole, less than 1/2", groups with a different technique.

    He is right about this little donut helping to hold the case in alignment in the chamber the round came out of. But full length resizing reduces the body diameter back to minimum specs and this causes the case to grow in length by squeezing the case, that is why he needs to trim so often. In any case he is unneccessarily working the brass, accurate load or not, and that is one big reason not to full length resize.
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  18. #18

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    What's your technique Murphy? And how often would you have to F/L size, he seems to think about every three times? I'll be using Norma brass. And he does use an F/L die.

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    If you are looking to wring out the last word in accuracy from this rifle (or any for that matter) you need to get dies that will make ammo that fits.

    Remember this, when they talk about SAAMI specs, they are talking about a range of sizes. You have a chamber at one size and you sizing die at another. For this reason when a custom die is made to fit your rifle there is a little bit more knowledge needed to make it perfect. The best dies I've worked with follow the one three methods to get you as near to perfect or perfect.

    The cheapest way to get you there, is with Neal Jones custom dies. It really depends on how serious you are about getting the most you can from any rifle. When you look at the price, you'll think twice. I can assure you this is the cheapest way I know to get you there.

    http://www.neiljones.com/

    If you decide to go this way, follow his instructions to the letter.

    I need to point something out about the idea of a false shoulder/partial neck size case. The chances of a factory chambered rifle that this will work in are vary slim. A tight necked chamber is a different beast all together.

    When you have a custom one off reamer cut for you, they will ask what dimension you want the neck? When a chamber is cut using this reamer, you may or may not be close to what a die maker will supply you with from stock. Brass cases normally have spring back of .001". I hope you are being to see where the problems with dimensions start to come in.

    I have prints from reamer made for me in the past, if you were to compare them to SAAMI prints you will begin to see where all the trouble comes in. Cause it ain't just the neck that will control how the bullet seated in the case that controls the alignment to the bore.

    I have pages of SAAMI prints and pages of custom reamer prints, what I don't have is a clue as to how to post them.

    One of the other methods is to have a what is called a re-size reamer made at the same time you have your finish reamer cut. Along with your two new reamer (finish and re-size reamer) you will need a headspace gage. You are now up to around the 500.00 range. Well you already have the chamber cut, so that means a re-size reamer cut for your chamber. That gets you to the 250.00 area. Of course that's before you have the die cut and hardened. Throw in about 150.00 more.

    Or, you can get Redding or Huntington die specialties to cut you a die for that chamber. Using a chamber cast from your chamber. That should get you to around 225.00.

    For me the solution has been to get my dies made by Neal Jones and save way more than half.

    Now before we see all the replies about what Bob or Harry does with their Lee dies in there old .30-30 (that their great granddaddy gave uncle Ralph) That shoots five shots into a 3/8" group at a hundred yards, leaning over the hood of their truck (open sights) in a gale. No you don't need to do any of this for your hunting rifle (unless you have a wildcat and want to shoot the rifle.) Or you are some kind of accuracy nut.
    "The tree of liberty must be refreshed from time to time with the blood of patriots and tryants." (Thomas Jefferson

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    Smile

    I own neck sizing dies for all my important calibers, almost all of them. There is no set number of loads that determines when and if I use a body or F/L die. When closing the bolt, I want a slight resistance at the last 1/2" of downward bolt handle travel. This is the caming action of the bolt making a crush fit of cartridge in the chamber. When loading a hunting load, I only use brass fired once or twice in that rifle, no more than twice. Hunting loadsmust be reliable first and accurate second but my very best accuracy from hunting rifles has been with these loads.

    I tumble clean brass after every firing and I closely inspect for neck cracks or any indication that the brass is stretching at the webb. (bright ring at the base) Belted cases that I load for dangerous game will be fired once in the intended rifle, no more. They will fit and they will not seperate in the chamber upon firing. The utmost in reliability must be the consideration rather than accuracy. I'll gladly take a 1.5 MOA load that is relaible.

    I have a lot more loading equipment than any ten normal handloaders. Any one can have the correct equipment for one or two calibers with a modest investment. I also use competition micrometer seater dies. These maintain concentric seating of bullets in the case and minimize runout. They are expensive and I realize most wouldn't want to invest in them. They help but mostly it is brass prep and correct sizing that makes good loads. Trim as necessary and chamfer, clean and uniform cut primer pockets each loading. When the case that is fired in a chamber fits, don't reshape it unnecessarily, that will reduce accuracy. Neck sizing maintains that fired shape as much as possible.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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