if you want to have concentric cases, nothing is even close to the lee collet dies, every one I have puts out cases within .001 every time. Don't know if that is necessary but no lube to put on and take off and the concentricity gauge doesn;t hardly move. I am going to load up for tomorrows match in a minute and will make 22 rounds for the 600 yd line in about 1/2 hour. The computor would not let my post this so I went and loaded tomorrows 22 shots for the match and I lied, It took me 37 minutes to check oal to the lands with 140 amax and size 27 cases I shot in todays match in the collet die by Lee and prime the cases and weigh the charges and seat the bullets, I changed the seating depth by020 and will see if I can tell the difference tomorrow
Tell me about mandrels? Use of, pro & con
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fire814
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Does the Lee collet give you good neck tension ?
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Here is another theoretical advantage(?) of a mandrel. Since it must overcome the yield point of the brass to expand it, it should theoretically get tighter rather than looser over time if it is going to move.
If your case trimmer uses pilots, the pilots may not fit, if the case neck has not had an expander button or mandrel run through it first.
Might want to consider upgrading from way back when you started 60 years ago. I undid what I learned 62 years ago. If you follow some of the replies the reason is explained in many of them.
the fingers on the collet get squeezed over a shaft which fits inside the neck of the case so if you are not getting enough neck tension chuck the shaft up in a drill and spin it putting sandpaper to the outside and reduce the diameter by a thousandth or so and try it again or call lee and they can give you one with a lesser diameter. these things work better than any other I have tryed for neck concentricity, all the ones I did last night were .001 out at the most.
fire814
Well-Known Member
Great, Thankyou
Some brass, like Peterson (7mm Rem Mag), takes a few firings before it settles down, even with annealing. Some, like Lapua, is good from the beginning. They don't make 7mm Rem Mag brass. I've seen the Peterson brass spring back. It took 4 firings before it stopped moving after sizing.
DMP25-06
Well-Known Member
I first tried using the mandrel that came with the die , but found that there was not sufficient neck tension to hold the bullet securely , I could push the bullet into the case with my thumb . So , I measured the diameter of the mandrel , and then contacted Lee Precision to purchase a mandrel that was .003" smaller than original (because I intended to have cartridges in my magazine while hunting , and I did not want rifle recoil to jamb the bullets back into the case).
On other rifles that I only loaded single shot , I ordered .002" smaller mandrels .
At that time , about 10-12 years ago , the new undersized mandrel cost $4.50 from Lee Precision .
Thank you
