Lee Factory Crimp Dies
Eliminate the Factory Advantage
With a Lee Precision Factory Crimp Die, you can crimp your bullets in place the same as factory ammunition. Roll crimps and taper crimps simply do not hold the bullet as firmly as a factory crimp. A collet in the Lee Factory Crimp Die gently but firmly squeezes the very end of the case into the crimping groove exactly the same as on factory loaded ammunition. You can see how this works in the cutaway view of a Lee Factory Crimp Die shown at right.
In fact, the Lee Precision Factory Crimp Die is so powerful it will even crimp bullets in place that don't have a cannelure. Now you can seat your bullets to the best depth and the Lee Factory Crimper will form a cannelure in the bullet as it crimps the case. The Lee Precision Factory Crimp Die crimps the bullet in place more firmly than any other tool allowing you to load ammunition better able to withstand rough handling because the bullet is firmly crimped in place.
Have you read those articles about how good modern factory ammunition is? Those who load ammunition for profit know that the single most important factor for achieving accuracy is a uniform start pressure. Start pressure is that pressure needed to start the bullet moving. Until now, handloaders tried to obtain a uniform start pressure by seating the bullet so it would just touch or nearly touch the rifling. This is not always possible or desirable. A firm crimp solves this problem and improves accuracy because pressure must build to a higher level before the bullet begins to move. This higher start pressure insures a more uniform pressure curve and less velocity variation. A firm factory crimp also supplies the uniform start pressure needed for ammunition loaded for different guns. Now you can match and exceed the conventional factory accuracy with little effort using Lee Precision Factory Crimp Dies.
More Uniform Velocity
Tests demonstrate bullets crimped with Lee Precision Factory Crimp Dies have significantly less velocity variation, especially when using less than optimum powders. This makes powder selection far less critical.
It is impossible to buckle the case with a Lee Precision Factory Crimp die as can happen with regular roll crimp dies. Tests demonstrate that even bullets which have no cannelure will shoot more accurately if crimped in place with the Lee Precision Factory Crimp Die. And a firm crimp doesn't increase maximum pressure for most rifles. In some cases, it may even reduce maximum pressure by smoothing the pressure curve.
- Overcomes the factory ammunition advantage
- No crimp groove require even with jacketed bullets
- More tolerant of rough handling, a must for hunting ammunition
- Powder selection is not critical
- Trim length is not critical
- Improved accuracy
Interchanging Lee Factory Crimp Dies
Lee Factory Crimp Dies are cartridge specific. However, some calibers share bullet diameter and trim length exactly. In such cases Lee Factory Crimp Dies can be interchanged.
Lee Factory Crimp dies generally use about .050" of the case to apply the crimp so any difference in the trim length between the cartridges comes off that amount. FS Reloading reccomends not interchanging calibers unless the bullet diamter and trim length match exactly.
Following are a few examples:
|Caliber||Lee Part#||Bullet Dia||Case Length|
|.221 Remington Fireball||.224||1.400|
|.223 Remington Ackley Improved||.224||1.760|
|.22-250 Remington Ackley Improved||.224||1.912|
|.257 Roberts Ackley Improved||.257||2.233|
|7mm Remington Magnum||90821||.284||2.500|
|.280 Remington Ackley Improved||.284||2.540|
|7mm Remington Express||.284||2.540|
|7mm Remington Ultra Magnum||90869||.284||2.850|
|7mm Shooting Times Westerner||.284||2.850|
|.30-30 Winchester Ackley Improved||.308||2.039|
|.300 Holland & Holland Magnum||90970||.309||2.850|
|.300 Remington Ultra Magnum||.308||2.850|
|.300 Remington SA Ultra Mag||.308||2.015|
Cartridge specifications shown above are for illustrations purposes only. Refer to a competent reloading manual like Lee Precision Modern Reloading 2nd Edition or Hornady Handbook of Cartridge Reloading Tenth Edition before loading any cartridge. Refer to the SAAMI Cartridge and Chamber Drawings for actual cartridge standards.
Speer advises that Speer Bullets should not be used with certain Lee Dies. All other brands work great!