I read the post below started by Sawblade about the Lee Factory Crimp Die. I just bought one for my 300 Win Mag. It should be noted that some stated that it was caliber specific when in actuality it is cartridge specific. I have a couple questions about the use of the die. Have those of you who use this die done much fiddling with how heavy of a crimp you apply? So far I have just done as the basic instructions which was to screw die in until it touches the shell holder, then back ram down and screw die in 1/2 turn more. Would more or less crimp be better? I suppose I will never know without trying but I am not wanting to do a bunch more testing. If many of you have done this test and found that 1/2 turn more is most often best for bottleneck cases then I would like to know that. Another question I have regards seating depth. Some have said that the use of the Lee crimp die drastically reduces the impact of seating depth on accuracy. Please elaborate. Are you saying that if you have worked up a load that shoots 0.7" groups at 100 yards without the crimp die and it is clear that the best seating depth is 3.500" without the die then when using the die altering the seating depth is not likely to make any significant difference in accuracy? Thanks, Rufous.

[ 07-22-2002, 19:29: Message edited by: rufous ]

It will make the groups worse,likely, as you are changing a variable.No the die is used from the first.

I crumpled some 45-70 cases with conventional seating and crimping simultaneously and have bought the lee die.

In 9 mm I dont use crimp, but run them through the Carbide factory crimp die.

If you have the perfect load this die will not improve on them. If you are starting load development, these dies might make you ~independent of seating depth. If you have to crimp hunting ammo, I recommend this die for a first try.

Buy one, go shooting, have fun! Hermann

In the .300 Win. Mag., the less crimp you use, the better!! NO CRIMP AT ALL would be best in this caliber!!

Eldeguello,

Guess I better throw those .300 Mag loads away.

Federal Gold Medal Brass
Fed 215 Primers
Nosler 220 grain Partition
76 Grains H-1000
Firmly Crimped with a Lee Factory Crimp Die
3/4" Groups @ 100 yds.
Velocity 2711 FPS average.

Good thing you warned us.....

Regards,

Bob

eldeguello,
How can you make such definite statemant? Put a three pack of heavy loaded UN-CRIMPED 300 WinMag in a BAR and see what you get after the first shot. A mess at best and a real painful accident maybe.

Rufous - Keep in mind the idea with a crimp is to HOLD the bullet in place in spite of recoil or feeding. The fact that this extra little "grab" on the bullet allows better ignition and more consistent loads often times...with a resulting slight improvement in accuracy is just a bonus.

What you DON'T want to do with any crimping die is DEFORM the bullet or case. That said I don't believe you should experiment with just how hard you can clamp these Lee dies down for the crimp operation. JMHO

Their great advantage over ordinary dies which do a Roll Crimp is it's danged hard to bulge the shoulder. Roll crimp is a good way to bulge this shoulder where it may not even chamber in the gun or could potentially even create headspace in some cartridges.

Lee either has a patent on this crimp die or the other die makers aren't very smart. If I were RCBS, I'd be pushing my own factory crimp dies.

But no guarantees you will get an accuracy improvement with these dies. However, there GENERALLY seems to be some increase in accuracy. Saeed has a good article on this subject on this website regarding his own tests.