Seat & Crimp in one step?


February 18, 2013, 06:20 PM
I see that the most common pistol die sets (from Lee) are the three die sets. So I have to guess that the most common practice is to seat the bullet and crimp in one step on a single die. But I hear many knowledgeable people advising to seat and crimp in separate steps, (obviously using a separate crimping die.)

So what do you do? Seat and Crimp in one step? Seat and Crimp separately? Or does it depend on other factors, like the round, the bullet, the gun? Please school me.

I guess I should mention that I'm asking this, assuming that you have the extra hole in your turret or progressive press, or the extra time for your single stage press.

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February 18, 2013, 06:30 PM
I depends on your process.
I use dillon presses.
They have an extra station where you put a separate crimping die.
That allows the bullet to be seated without the crimp effecting the overall depth of the bullet.
Then the crimping occurs in a different station, with a separate die.

If you are loading on a single stage press, you can set your seater to seat only and not crimp, and then run them through the press again to crimp them.
If you are loading on a progressive press that does not give you an extra station for a separate crimp die, then you would set your seating die to do the crimping as well and just not worry about seating lengths being effected by simultaneous crimping.

February 18, 2013, 06:37 PM
I only crimp handgun cartridges but I always seat and crimp in one step if I can. Thats everything but with one bullet in one cartridge where I seat and crimp as a 2 step process.

In my mind seating and crimping separately makes complete sense when there is a problem doing it in one step. OTOH doing it as two steps when there isn't is just creating work for yourself. The exception would be on progressive presses where there are extra stations so it really doesn't matter.

February 18, 2013, 07:05 PM
If taper crimping, I seat and crimp in seperate steps. With roll crimp, I do both at the same time using same die.

February 18, 2013, 07:26 PM
If taper crimping, I seat and crimp in seperate steps. With roll crimp, I do both at the same time using same die.

That's kinda what I'm wanting to find out. I currently only load auto loads, 380acp, 9mmL, 40S&W, 45acp. I've always felt better doing separate operations on these rounds.

Now I'm wanting to start loading 38/357 and 44sp/44mag, and I was wondering if it would be worth spring for the four-die sets.

February 18, 2013, 07:41 PM
^^^ I do the same thing as #4. The taper crimp action is more unforgiving due to case wall thickness with lead bullets so I do it as a separate operation.

February 18, 2013, 07:42 PM
Some cast bullets have long tapered crimp grooves that work well with roll crimping in 1 operation. Others will work best using separate operations. If shaving lead, separate is better. But shaving can be caused by an undersided seating die removing the bell to soon.

February 18, 2013, 07:42 PM
The only pistol round I reload for is 9mm and I seat and crimp in the same step. It took a bit of experimentation and a few messed up rounds but, I can consistently get the seating depth and crimp that I like in one stroke.

February 18, 2013, 08:41 PM
I always seat and crimp in one operation. Care must be taken in setting up the die. (

February 18, 2013, 08:43 PM

February 18, 2013, 08:48 PM
When taper crimping such as 45acp 9mm and such and other cartridges that head spaces on the mouth you don't have to separate operations as a rule, but rimmed cartridges and rolled crimping you can have variance in slight length of cases and you start jamming case mouth edge into bullet crimping grove and it will pucker the roll on your casing , because your seating the bullet and rolling at the same time it is not as forgiving. MAYBE somebody explain this better!

February 18, 2013, 09:03 PM
Many reloaders will do this in two steps, but I personally have always had good results using the seating die in one single step. When it is adjusted correctly, it is as simple as setting the bullet on top and pulling the handle.


February 18, 2013, 09:04 PM
Every bullet potentially raises new challenges. I almost always experiment with a few rounds before deciding which way to go, and sometimes I find with non-cannelured bullets I don't have to apply any crimp at all.

February 18, 2013, 10:52 PM
With semi-auto handgun cartridges, I have always seated and crimped in separate steps. Back when I got started reloading in 1980, many seater dies came with a roll crimp regardless of cartridge so a separate taper crimp die was needed if a taper crimp was desired.

On the single stage press, i would still roll crimp at the same time as seating the bullet for revolver cartridges.

Since I got my Hornady L-N-L progressive, I can more easily crimp in a separate step for all handgun so I have added separate roll crimp dies where I did not have them before.

But it is one of my idiosyncrasies. Folks have seated bullets and crimped in the same die for longer than I can remember or been involved in reloading.

Finally, I do not change bullet style/type very often in a particular cartridge any more so i do not need to reset my dies very often. Nothing wrong with trying different bullet styles or shapes, just I have "been there/done that" and do not need to continue doing it. Another idiosyncrasy

February 19, 2013, 01:35 AM
Most of the time I do it in the same step. (On straight-wall pistol cartridges.) But I have one .45 that is so finicky, I just can't get it right. So I bought the Lee Factory crimp die, (RC told me not to, but all the reviews on Midway made it sound like it was the solution to my problems. So I have been using it, seating with the regular die, and seating (and also sizing again) through the FCD, they feed a lot better, as soon as my busted wrist heals enough for me to rack a slide I'll see how well they shoot.

February 19, 2013, 07:35 PM
I "always" seat and crimp in one step.

Now, some hollowpoints have such a fragile mouth on them, you need to either fit a custom seating plug or crimp in a separate step. And some lead bullets just can't be done in one step without shaving.

So what I have done is to make custom seater plugs for said hollowpoints. And so far I've been able to avoid the cast bullet problem, altogether. My 45ACP Glock is my only handgun that needs a taper crimp for proper chambering. The only cast bullet I use for it is an MBC revolver bullet with a crimp groove. When I taper crimp at the groove, there's no shaving. (And this bullet is very accurate and 100% reliable in my gun). The rest of my cast handgun bullets for rimless calibers, I don't use any much of a crimp, at all. Just enough to touch the flare on the longest of the cases.

When roll-crimping revolver and rifle bullets, I've never found a need to use two steps. Although that experience is limited to cast bullets with grooves.

February 19, 2013, 09:20 PM
I awawys seat first then put the LFC die in and crimp. 44mag and 45/70

February 20, 2013, 03:47 PM
Seating and crimping works fine if you have the die adjusted correctly, and your brass is all the same length. I reckon there were a lot of rounds reloaded with no problem before anybody marketed a "factory crimp die".

February 20, 2013, 06:23 PM
I seat and crimp at the same time when usning bullets having a proper crimp groove, that is beveled at the bottom. Otherwise in two operations.

41 Mag
February 20, 2013, 07:13 PM
Once upon a time I would have said seat and crimp in one motion.

Now however I am learning all about lead and it's reaction to just such an adventure. LOL

Seating and crimping at once can sure do some funny things to a soft lead HP for sure.

Since I started casting my own HP's I have beguan to also seat and crimp in a separate step. I just hate to go to all the trouble to pour up some great looking HP's and then squash some of then while seating and crimping.

Steve C
February 20, 2013, 07:25 PM
I generally seat and crimp revolver ammo and rifle ammo in one step unless there is difficulty in the process like bulged cases or other issues. Semi automatic ammo is usually loaded with a separate crimping step.

February 20, 2013, 08:20 PM
I crimp straight case in one step if a crimp is needed.
I don't crimp cases that head space on the end of the cases.
I crimp bottle neck cases for semi-autos as a separate step.

February 20, 2013, 09:42 PM
For my revolvers I roll crimp in a separate step. On my semi auto rounds they just get a kiss of a taper crimp while seating the bullet.

February 21, 2013, 11:23 AM
I crimp most of my handgun loads with a Lee Factory Crimp die except my 9MM Makarov for which Lee doesn't have a factory crimp die. I crimp my 38/357 & 44 in a single operation when needed. I crimp my .223 Remington loads with a Lee Factory Crimp in deference to my son's Mini 14. The rest of my rifle calibers do not need crimping.

February 21, 2013, 06:45 PM
With jacketed or lead bullets, seating and crimping together works fine. If you use plated bullets, seperate steps are necessary.

February 22, 2013, 12:48 PM
If you taper crimp it is better to crimp in a separate operation. I was using RCBS dies to load 9mm, the nose of the bullets were being deformed in the process. Seating the bullet and then crimping afterward solved the problem. I don't see any difference in revlover ammo where there is a crimp groove. Bullets without the crimp groove should be taper crimpped after the bullet is seated.

February 22, 2013, 01:08 PM
The majority of my handgun loads, both revolver and autoloaders, are seated and crimped in one step. I have done testing for accuracy doing both and the difference is so small that for me, the majority of the time, it is not worth the extra step on the single stage press. Exceptions are when loading .460 ammo. It's hard to get enough crimp on that long of case in one step without the risk of buckling cases. In my other magnum revolver ammo, I've found that trimming cases for consistent length in hunting ammo is more relevant for consistent accuracy than seating and crimping in two steps.

February 23, 2013, 12:43 AM
When I first began reloading I seated and crimped in one operation but as time went on I went to seating and crimping separately. I use the Redding Profile Crimp dies for my .357 Magnum rounds, and LEE Factory Crimp dies for my .40 S&W and .405 Winchester.

I like the versatility that the separate operations give.

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