I'm currently using Lee Collet dies for reloading my .308 Win. I'm using Lapua brass and 175 grain SMK's. I'm not sure how much tension there should be when I seat the bullet, but the bullet seems to slide into the case with very little effort. I hardly have to put any pressure on my press. Should the bullet be tighter in the case, or is this desirable? The gun I have now is a basic Remington 700, but i have a Savage FCP-K on order, so i want to make sure everything is right for the new gun. Thanks in advance!
Lee Collet Dies
- Thread starter thommy152
- Start date
Re: Lee Collet Dies
.001-.002" sized neck diameter under loaded round diameter is what I shoot for. For magazine fed bolt guns I try to keep it around .002 neck tension.
the lee collet die usually gives around .001 Neck tension. If you can seat a bullet and it won't turn in the neck with your fingers or move with firm pressure, you're probably ok.
Measure a loaded round, then take an empty case and size it with your lee collet die. Subtract the difference and that will give you an idea of what your Neck tension is like.
If you have a micrometer measure the actual thickness of your necks, multiply by 2, then add .308 for your bullet diameter and that will get you a more accurate reading on your loaded neck diameter.
Then mic your sized case neck and subtract the difference to get your neck tension.
As your necks work harden, the lee collet die won't size your necks as much, and you'll need to anneal your brass...however, I've never been able to get good results after annealing with the lee collet die. It scratches the brass really badly and some of them end up sticking somehow after annealing and crunching the case neck. My poor technique in using the die I'm sure...
Finally, if you find your Neck tension isn't adequate you can either polish down the center mandrel another .001 or so with some fine grit sandpaper or order an undersized mandrel directly from Lee Precision.
There's more involved in neck tension than that. How much force is actually holding the bullet by the brass really can't be quantified just by the diameter of the brass neck but, for simplicity sake it's easier to measure this way. At least for me.
Hope that helps.
.001-.002" sized neck diameter under loaded round diameter is what I shoot for. For magazine fed bolt guns I try to keep it around .002 neck tension.
the lee collet die usually gives around .001 Neck tension. If you can seat a bullet and it won't turn in the neck with your fingers or move with firm pressure, you're probably ok.
Measure a loaded round, then take an empty case and size it with your lee collet die. Subtract the difference and that will give you an idea of what your Neck tension is like.
If you have a micrometer measure the actual thickness of your necks, multiply by 2, then add .308 for your bullet diameter and that will get you a more accurate reading on your loaded neck diameter.
Then mic your sized case neck and subtract the difference to get your neck tension.
As your necks work harden, the lee collet die won't size your necks as much, and you'll need to anneal your brass...however, I've never been able to get good results after annealing with the lee collet die. It scratches the brass really badly and some of them end up sticking somehow after annealing and crunching the case neck. My poor technique in using the die I'm sure...
Finally, if you find your Neck tension isn't adequate you can either polish down the center mandrel another .001 or so with some fine grit sandpaper or order an undersized mandrel directly from Lee Precision.
There's more involved in neck tension than that. How much force is actually holding the bullet by the brass really can't be quantified just by the diameter of the brass neck but, for simplicity sake it's easier to measure this way. At least for me.
Hope that helps.
Re: Lee Collet Dies
The Frogman gives you good info. Fact is, no matter how far undersized a neck is, it's virtually meaningless if it's smaller than about 1 thou. More than that, the brasss will stretch passed it's elastic limits and bullet grip will not be increased anyway.
All we get with "high bullet tension", as most people intrepet it, is higher seating resistance. If you can't move a seated bullet with your fingers it's tight enough. With the Lee collet die, if you can move them the necks need to be annealed.
The Frogman gives you good info. Fact is, no matter how far undersized a neck is, it's virtually meaningless if it's smaller than about 1 thou. More than that, the brasss will stretch passed it's elastic limits and bullet grip will not be increased anyway.
All we get with "high bullet tension", as most people intrepet it, is higher seating resistance. If you can't move a seated bullet with your fingers it's tight enough. With the Lee collet die, if you can move them the necks need to be annealed.
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