Crimping Die separate from Seating? Needed?


December 3, 2006, 09:38 PM
I've been using this RCBS die in my Rock Chucker and I've noticed zero problems while crimping (taper) and seating the bullet at the same time. I've got plenty of accuracy and have had no problems with plated or FMJ bullets. I reload 9mm, .40S&W and .45 ACP. Anyone else still do this? I'm thinking of going pregressive soon and don't desire to buy more than the std 3 die sets I have.


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December 3, 2006, 09:58 PM
I reload 45 colt with lead bullets, roll crimped. I tried the Lee FCD, and did not like it as well as the crimp from my Hornady seating die. If you make sure your brass is uniform length, and take your time setting it up, I believe crimping while seating can do as good a job as with a separate crimper. On the other hand, when using a turret or a single stage press, separately crimping takes an extra step, which is not really an extra step on a progressive. On the other other hand, especially if you have a 4 station 550, seating and crimping in one step will allow the use of a powder cop or lock-out die. Folks were doing just fine seating and crimping in one step for a long time before Dillon figured out they could save money on customer support and cheaper seating dies, while making more money on bigger presses and extra dies, by recommending separate crimp dies.


December 4, 2006, 08:46 AM
Without going into all the details, you WILL load better ammo with separate seating and crimping dies. Number one reason would be uneven case OAL. Crimp dies are cheap, especially if you switch to a progessive press. I have also found that the Lee FCD no better than the standard crimp die from Redding or RCBS. JMHO:)

December 4, 2006, 09:27 AM
It's easier to get good crimps with a seperate die, but not absolutely needed. I prefer a seperate die.

December 4, 2006, 09:52 AM
If it ain't broke, don't fix it.
I like using Lee crimp dies for lead bullets. I think I get a more consistant OAL and less bullet shaving if I seat and crimp in seperate steps. I load on a blue 650, so it isn't an extra step.

December 5, 2006, 02:19 AM
If you are shooting jacketed bullets, there isn't much need to seat and crimp in seperate operations.

However, if you are loading lead and/or copper plate bullets, you will get much greater accuracy by seating and crimping in seperate operations. This keeps the case from either shaving lead off or biting into the lead as it goes down, which can cause over diameter expansion, and/or distortion of the bullet.

I have both a 550 and a Hornady LNL Auto. The 550 is dedicated to 38/357 and it requires a second run thru of the cartridges with the crimp die lowered. This was a major pain in the carbarosticus maximus, so I got a factory crimp die in a Horndy bushing, and in less than 30 seconds the Hornady progressive is performing crimp only operation.

The Hornady progressive is a 5 station press (which is less in price than a 550 and several hundred less than a 650), It is ideal for the seperate seat/crimp operation, and only takes 2 seconds to remove the crimp die for single crimp operations on jacketed booolits.

December 5, 2006, 04:16 AM
Not nessesary, but seperating the seating and crimping sure is eaiser, and good exersize:D

December 5, 2006, 06:17 AM
I'm suddenly hearing a lot about 'crimping', and I'm beginning to wonder if I've missed something.
Most of my reloading knowledge comes from an old (1970's era) Hornady handbook, which will be remedied when I acquire a copy of the ABC's of Reloading.
However, crimping is not mentioned as far as I noticed.

The second-hand reloading setup I bought recently had a set of RCBS carbide .45 ACP dies, which I assumed would be all I needed to start cranking out .45 cartridges (as far as putting it together after priming/charging).
Am I going to have to buy another $30 die for every cartridge I intend to load (mostly necked rifle cartridges), or is crimping just a 'nice touch' step?

December 5, 2006, 07:30 AM
You don't absolutely need another die ...and a crimping die is typically around $10-$12 in my experience.


December 5, 2006, 03:22 PM
Koobuh, most seating dies will also crimp- basically squeezing the case mouth in just a bit to bear on the bullet. In bullets with a cannelure(groove) around them, especially on heavy-recoiling loads or loads for tube-magazine rifles it's a good idea to adjust it so the case mouth is pressed into the groove.

Take a case, set it in the shellholder and run the ram all the way up. Then screw the seating die down until you feel it touch the case mouth. Back the case out a bit, then turn the die down another 1/4 turn, then run the case up all the way and take a look. Most dies you'll see the case mouth rolled in just a touch; that's a roll crimp. A taper crimp is where instead of rolling the mouth in, the crimp is just enough taper in the die to press it against the bullet.

Most handgun and some rifle cartridges you expand or 'bell' the case mouth a touch to make it easier to seat a bullet, especially a cast bullet so you don't shave lead off the sides. The crimp can be used just enough to close that bell up around the bullet, or more severe to really clamp the bullet in place.

In many(some say most) rifle ammo, crimping isn't required, in which case you just adjust the lock ring on the die so the crimp shoulder doesn't touch the case.

I tried a Lee Factory Crimp Die a few years ago, and in some cartridges it gave really nice results, so I use it on them. On cast loads I use the crimp shoulder in the seating die to form the case mouth to remove the bell.

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