Neck sizing only, then crimp?

geetus

geetus

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Hey lads, I just got a Lee Deluxe kit and have been doing some testing and measuring before making up any real loads. I have it all setup as per instructions but I find that after I size a piece of brass the neck still seems loose. I mic'd the inside of the neck at around .308 and that is with a good deal of force on the press. Do I have to "come on to her" more or can I use the Lee factroy crimp die that I have to tighten the hold on the bullet?
These are loads for an Norc M14 and a Rem 700tac, and brass is seperated according to its respective gun it was fired in.
 
If you mean that a bullet can be pushed into the sized neck by hand, then a crimp will not help.
The main force to hold the bullet in the case is the neck tension, created by the bullet being held tightly by the brass (pushing a .308 diameter bullet into a hole that is about .306 (or so). If you mean to use these in a semi-auto, it is even more important.
 
The basic way to determine neck tension is to measure the sized neck OD (to the 1/10th of a thou), then seat a bullet, and measure again. The increase in diameter is the tension. If you use a flat base bullet, they most likely will have a pressure ring, or slightly larger diameter ring right at the base. Most will measure the neck where the pressure ring is located. Target shooters will generally shoot for 0.001" tension when single feeding. For hunting or magazine fed guns, you want 0.002" or a bit more.

I think the issue with the Lee Collet is that you are squeezing the neck against a mandrel, and it can be torque sensitive. One user recommends a torque wrench to get right. See this thread. Jerry Teo of Mystic Precision gives some tips on using the Lee at his website. Some suggest you may have to sand down the mandrel to increase tension. Not much has to come off it.
 
For more reliable function in your M14 I would think full resizing would be better with a good crimp after. Neck sizing for your 700 should be good. I have never used the Lee neck size die so I'll leave that for others. Just my .02 and worth what you paid for it.
 
I like to say .002" tension and the best way to ensure this is with a Forster or Redding bushing neck size die, where you can buy diff. bushings to fine tune your case neck tension and more importantly make sure that each case has the same neck tension which is very important for top accuracy.
 
Your M305 requires FL resizing. A crimp shouldn't be necessary. Neck tension should be enough.
You shouldn't need to muck around with measuring the necks either. The sizer die will size the case mouth properly all by itself.
Have you checked the case lengths, trimmed as required and chamfered and deburred the case mouths?
 
I think if you look in the instructions, Lee says they will sell you a smaller mandrel for about $5. A few years back I tried a Lee collet neck sizer ... neck tension was insufficient... I paid $5 and they shipped me a smaller one. In the end, I abandoned the collet neck sizer.
 
Couple of good articles there Ron AKA. Real good reads. And that is a nice tip for measuring the OD of the case neck to gauge bullet tension.
I have a LEE pacesetter set, with factory crimp that have been using that for a while for all my .308 reloading. It works just fine, but I bought this setup to play around with neck sizing.
I just found that after sizing the neck only, the bullet seemed to seat not as tight as I felt it should.

And JEC, I went back and re-read that part about buying the smaller mandrel. Thats one option, but i may try to polish up the mandrel to see if i can get a bit more tension that way.

Cheers guys, thanks for the advice.
 
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