1. Two versus Three Die Sets (3 die sets)
NOTE: OLD STYLE PISTOL DIES ARE DIFFERENT FROM THE NEW STYLE. OLD STYLE RESIZES ONLY ON FIRST STEP, THEN 2ND DECAPS, BELLS MOUTH AND REPRIMES AND FINALLY THE 3RD DIE SEATS THE BULLET AND CRIMPS.
NEW STYLE 1. RESIZES, DECAPS AND REPRIMES, THEN 2. BELLS MOUTH AND FINALLY 3. SEATS BULLET AND CRIMPS. SOME 4 DIE SETS HAVE THE 4TH DIE DO THE CRIMPING, PARTICULARLY A HEAVY ROLL CRIMP.
(Also see “Steps of Reloading” for reference) – – The three die sets are usually the pistol cartridges. These often use cast lead bullets and even when bullets are sized and lubricated, some lead can be shaved off if the case mouth does not have a slight “flare” or enlargement just where the bullet enters the case. This flare is closed when the bullet is seated or even reversed if you seat the bullet deep enough to crimp the case mouth.
The first die of 3, usually just re-sizes (old style) the case back to original size specs. (New style de-caps in first die) The second die will de-cap (remove the primer) from the case and “bell” or open the case mouth up just slightly. You control how much opening occurs by how deep you insert the case into the die. This is adjusted by how deep the die is screwed into the press and the lockring on the die is set to the depth you prefer. This is the step where you put the new primer into the case.
The last of the three dies is for bullet seating and closing the mouth of the case even or even crimping the case mouth on the bullet. Lead bullets usually either have a crimp ring or can be inserted just deep enough to get past the largest part of the bullet to put a slight crimp on the case. Be warned, the more crimp you put on the case, the sooner these cases will begin to split at the mouth and will have to be discarded. For this reason, many re-loaders will not crimp at all if the bullet is going to be used in the clip magazine. In Tubular magazines, the pressure on the bullets and recoil shock will often dislodge a bullet that has not been crimped. Again, the amount of crimp is adjusted by how deep the case is inserted into the die (and set by the lock ring on the die). THEN, the depth of the bullet seating is adjusted by the rod in the center of the die (and locked in place with a lock ring) so that the crimp occurs exactly when the bullet is seated to proper depth in the case.
2. Two versus Three Die Sets (2 die sets)
Usually these sets are rifle sets, but may be pistol sets also. The first die is the re-sizing die and the de-capping die. You put the new primer in this same first step. Some dies will also include the option to open the case mouth up slightly at the extreme end of case travel. Some, further have an adjustment and set screw so that the decapping pin is also the pin near the top that will open up the case mouth slightly. Some first dies do not have this option, as it is not usually needed. With high power rifle ammo, you are usually using a copper jacketed bullet. Most of the bullets have a slight indent at the base of the bullet and will begin the seat in the case with no widening of the case mouth at all, and will make a very snug fit that won’t have to be crimped. But, if you plan to make some low powered, lead “plinkers” in these cases, you would proceed like loading lead pistol ammo.The second die in the 2 die set is for bullet seating and crimping if you desire to do it. The same rules apply for crimping with the 2 die set as with all others. If the bullet, like a 30-30 is going to be in a tubular magazine, it may be wise to get bullets with a crimp ring and put a small amount of crimp on it. Just a side note, when using tubular magazine, it’s not wise to use spire pointed bullets that will put all the pressure on the primer of the bullet on top of it. It could cause an explosion. Best to use FLAT nose or gentle rounded nose bullets in tubular magazines.
3. Quality of Dies and Steel
One of the most important factors that I have found critical in dies is the hardness of the steel and the polish of the inside (particularly the re-sizing die). The best dies are made of Tungsten Carbide and are not supposed to need lubricant. I would use it anyway. The re-sizing die gets a LOT of hard work. Sometimes, even a case you have cleaned and lubricated, will still have a speck of sand or dirt on it. In the resizing die, it can scratch the die and then, every case sized after that will have a scratch put on it. Buy high quality dies. The extra cost up front will be well worth it in the years to come. Of course, you still should take special care to have cases clean and free of dirt, sand and grit.