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Posted: 5/10/2010 3:23:14 PM EDT
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Currently I am having an arguement with my dad about how far an expander die goes into the case. He says that the die only touches the mouth of the case but I believe that the expander die goes into the case mouth until the case reaches the tapered portion of the expander bell and I understand that the shaft of the expander helps to keep the case from crumpeling. Unfortunately I could not find a good picture of the areas I am talking about, but if need be I can scan them out of my reloading manual. Any help would be appreciated and I know how much ARFcom loves to settle debates with authority so I should be able to get an authoritative answer here.
Thanks TKolbus |
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Dad is right if he's thinking about Lyman M dies. You're right if you're equating expansion with flaring. I suppose some dies that flare also expand the neck after the sizing step, I never checked the diameter. I have one or two sets that do not use an expander ball in the sizer and rely on that in the expander die. So it depends. |
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I guess that I should have clarified that these are RCBS dies and my reason for thinking that the dies go in so far is that the case needs to be inside sized (the first part of the die) and when I take the belling/expanding slug out of the die I can see where brass has been deposited on the tapered part of this slug suggesting that the die does indeed go further into the shell than just touching the mouth.
I know I am being very unclear with what I am talking about but this has become somewhat heated, not that I care too mauch about the argument itself but I want to know if I am running the die too far into the shell. TKolbus |
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If you disassemble the mouth belling die (I think that's what we are talking about) you will clearly see brass marks all the way to the point where it just begins to flair. That entire section, or shaft if you prefer, is completely inside the case neck, but only the flaired part expands the mouth. This would be typical of Dillon's progressive expander/powder dies on the 550.
There is also certain belling dies that come from the major makers that basically have a round ball more or less. These are the type your father is referring to. Those styles do not enter the neck area to speak of. They only flair the mouth. So you are both right or wrong, depending on how much longer you want this to continue 
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There's a way to test both theories with your die.
Size two cases. Run the die down until the expander touches the case mouth on one, run it down far enough to flare the case slightly. Try to seat a bullet in each case. Use the result of that experiment to figure out how the die is supposed to be used. Also, sometimes it's better to recognize the path of least resistance. If your Dad won't believe the results of the experiment, or the fact that there are several types of neck expanders on the market, just press on and assemble your ammo the way you want and let him put his together according to the way he thinks. The RCBS dies have instructions. You could also call their customer service line tomorrow to get the manufacturer's recommendation. What cartridge are you loading? |
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As to the cartrige that we were discussing today, I was loading .380 and was having some trouble with the projectile being too loose if I don't use a taper crimp. He says that I am infact belling the whole case too much in essence oversizing the case and that is why I am having to crimp because the case tension alone should hold the projectile. I just want to make sure that my die is set correctly. I believe that it is because I have a noticable bell of perhaps .005-.008" but if I adjust the die any further upward this disappears and I start to have problems with crushing the cases.
Thanks for all of the helpful information I think that I do infact have my die set properly and crimping is necessary to get the tension that I am looking for. I knew this was that place to seek some honest answers. Thanks Again TKolbus |
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Typically most straight wall pistol cases need some amount of belling or you may have issues seating bullets like you have noticed with the crushed cases.
The general rule about taper crimping straight wall pistol cases is to only crimp enough to remove the bell but not cut into or squeeze the bullet. This is usually so the finished round doesn't have issues chambering. You can test this by measuring the mouth, using a case gauge, or taking your barrel out, if possible, and using the actual chamber as a gauge. How are you determining that your bullets are too "loose" without adding a crimp? Have you measured your bullets? |
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