i am obviously new and have learned sooo much thanks to all of you who have helped. lately i have been reading about crimp grooves, creating crimp grooves and tapers crimp dies for automatic pistols. I have recently loaded my first five 9mm rounds for a Kahr P9. TOLD YOU I WAS NEW! I am using a Hornady LNL Classic SS w/their 3 die set. I have not fired the first 5 rounds yet, but I used Winchester brass, cci primers, Unique powder and Hornady XTP (124 gr) bullets. Would I be better suited if I added a taper crimp die? what is the difference btwn the die that came in my set and a taper crimp die? What taper crimp die would you recommend? Also, can someone please explain what crimp grooves in a bullet are and how to identify them?
If a bullet doesn't have crimp grooves built in already, what tool would you recommend to put a crip groove in the bullet (if that is even possible)?

thanks and sorry for the noob questions

A basic rule of thumb, taper crimp for autos, roll crimp for revolvers. A taper crimp die gently tapers the loaded round. A roll crimp gently rolls the mouth of the case into the crimp groove. With the proper die setting you can roll crimp any round, and you can also taper crimp rounds for use in revolvers. I like Lee's taper crimp dies.

one note - if you load any of the plated bullets, do not use a roll crimp. it cuts through the thin plating. taper crimp works fine.

Never roll crimp ammo for auto pistols. They headspace off the mouth of the case and a roll crimp can prevent this.

Use a taper crimp for autos.

For heavy recoiling revolvers a firm roll crimp can be necessary to prevent bullets from extruding forward due to recoil and preventing the cylinder from rotating.......................DJ

thanks everyone. can u now recommend a taper crimp die that is good?

I also was wondering this...My current Hornady die does the bullet seating and the crimp. If I get a taper crimp die, does it also do the seating and the crimping or do I use it to taper the crimp after the seating and crimping die?

Hope that makes sense. Like I said, i am new.

CH makes a Cannelure tool to put the crimp groove in bullets I bought mine years ago when they were like $30 I think there double that now.

If you buy a taper crimp die, that is all it will do, it won't seat the bullet.

If you are going to have a seperate die for your crimp, then set up the seating die so it will not crimp, and use the taper/crimp die to do this by itself.

Kind of hard to recommend a specific die manufacturer. They are all okay for the most part. I tend to use Dillion for the pistol die and redding for all my rifle. Just the way I did it.

I have used Pacific/Hornady taper crimps on my 9 MM and 45 ACP for the past 25 years or so. Like was mentioned earlier seat with the regular die and start flattening the bell out then finish off with the taper crimp.

Greg

okay. I did order a taper crimp die today, but I had already reloaded a handful of 9mm rounds using the Hornady Nitride 3 die set, which I believe creates a roll crimp. I went to the range today to try them out and I didn't have any problems. I was a little worried since one of you stated the following...

"Never roll crimp ammo for auto pistols. They headspace off the mouth of the case and a roll crimp can prevent this."

Can someone please explain what the above means? I am not sure what headspacing off of the mouth of the case means. As I mentioned, I did not have any issues, so any ideas why I didn't have problems caused by the headspace issue mentioned above.

Thanks

Head spacing of the case mouth means that the case is physically stopped by the mouth of the case when it hits the end of the chamber. If you roll crimp you turn this edge inward and the case can enter the chamber too far and cause reliability issues. You see this in auto pistols.

The taper crimp merely holds the bullet yet leaves enough of the case the right length to set the round up properly in the chamber.

Revolvers head space off the rim and that stops their movement. The 45 caliber 25-2 Smiths can use 45 Auto Rim cases that are basically a rimmed 45 ACP round. If you load them with regular 45 ACP cartridges they will fire but then you have to punch them out with a pencil. That is where the half and full moon clips come in on those guns.

Greg

PS: The roll crimp will not give you as good an overall crimp and MAY allow the bullet to set back more on chambering.

quote:

Originally posted by PaseMkr:
... I did order a taper crimp die today, ...

Darn shame I didn't see this thread sooner. I'd have recommended that you should have called Hornady Customer Service and ask if the Die in that Set was a Taper Crimp. Since all the 9mm Firearms I am aware of Headspace off the Case Mouth, I'd think Hornady would only ship the Dies with a Taper Crimp.

There is no logical reason to ship 9mm Die Sets with Roll Crimps that I am aware of. Sure DO NOT need to Crimp in a Cannelure at that Recoil level if the Sizing Die is doing it's job properly.

Call them and ask, you can always return the Taper Die if it is not needed.

Best of luck to you.

quote:

Originally posted by PaseMkr:
okay. I did order a taper crimp die today, but I had already reloaded a handful of 9mm rounds using the Hornady Nitride 3 die set, which I believe creates a roll crimp. I went to the range today to try them out and I didn't have any problems. I was a little worried since one of you stated the following...

"Never roll crimp ammo for auto pistols. They headspace off the mouth of the case and a roll crimp can prevent this."

Can someone please explain what the above means? I am not sure what headspacing off of the mouth of the case means. As I mentioned, I did not have any issues, so any ideas why I didn't have problems caused by the headspace issue mentioned above.

Thanks

It's almost Allways better to seat and crimp in separate steps. If you do both at the same time a little mistiming can cause collapsed or bulged case shoulders etc. (in bottleneck rifles mostly).

Most of the brands of taper crimp dies should work just fine.

As mentioned above the reason you don't want a roll crimp is that it actually bends the front of the case mouth in and that could cause a bullet to go too far into a chamber on a semi-auto.

I don't think that you can taper crimp and seat in the same operation. I've never seen a die set that did so - maybe someone else has. With a taper crimp die you are squeezing down the sides of the case so you would just be making seating much harder. You CAN roll crimp while seating because it occurs in just the last few thousands of the stroke. It's still best to do either in a separate step.............................DJ