"Factory Crimp Die"

[WildRose]

Until recently I'd never given any thought at all to crimping any bottleneck rifle cartridges at all other than those intended for use in semi or full auto rifles.

I keep seeing "factory crimp dies" advertised for various bottleneck centerfire rifles and so I got to wondering why one would want to put any sort of a crimp on them?

What would be the logic behind crimping ammo intended for use in bolt action, falling block, or breech loading centerfire rifle cartridge?

 

[rcoody]

Only thing I would crimp is pistol and rifle rounds in a tubular magazine

 

[gohring3006]

I have been thinking of trying one to see if it lowers ES.
They are pretty cheap, I'm not holding my breath but I think it could hold onto the bullet a little longer getting good ignition. I have heard primers can actually send the bullet out of the neck before the powder ignites. I think that it would be significant if I can delay this...

 

[catamountsierra]

According to the literature from Lee Precision, it should make the pressure at which the bullet starts to move more uniform. I use them for most of my rounds after noting that my group size with my old 22 Hornet dropped in half when I started using one. I have since used it on all of my reloads except for the 45-70 (I don't have the die). I like it, but I can see why people wouldn't. I try to keep the crimp to a minimum and have good results, but I have also squished bullets pretty good and that can cause problems.

 

[fiftybmg]

Prevents setback on the rounds in a magazine due to recoil impact.

 

[RT2506]

I have done a lot of experimenting with the Lee factory crimp dies in a number of old military rifles. Many of them have a throat a mile long and the bullets have to jump that mile. Long story short, Lee Factory Crimp Dies improve accuracy greatly in these rifles. I have not tried the dies in my modern rifles because they shoot mostly bug holes or they don't stay around long.

 

[WildRose]

Prevents setback on the rounds in a magazine due to recoil impact.

The only problem I've ever noticed along those lines was the deforming of soft points and hollow points.

The bullet I loaded for 7mm's for a very long time was a Hornady bullet that had a cannelure ring on the outside which was obvious and I always loaded just short of it so it would remain visible. I never noticed in either the 7mm Rem or 7mm STW that it "moved" relative to the case neck but who knows, it may have and I just didn't notice.

The ideas about more uniform pressures and delaying the release of the bullet ever so slightly so as to get more complete and uniform powder ignition make sense.

 

[tbrice23]

I've never felt comfortable crimping any bullet that doesn't have a cannelure. However, I recently tried the Lee FCD in my LR260 when doing a load development with 123 Amax and Varget. The results were great. My next loading I forgot to crimp again because I never do it in my regular loading steps. The groups were definitely worse.
I have put a ( PROPER ) Lee FC on a bullet and then pulled the bullet to see if there was any visible deformation, I couldn't tell at all by my eyes. I'm sure one could go overboard on a crimp by setting the die up wrong and deform a bullet but the die is pretty easy to set up correctly.

I'd say its worth a try.

 

[Pdvdh]

It can improve accuracy with hand loads when the bullet isn't jammed into the lands. That's my theory.

 

[Pdvdh]

A similar Thread discussion from not too long ago.

http://www.longrangehunting.com/forums/f28/crimping-belted-magnum-loads-do-not-do-171747/

 

[WildRose]

I've never felt comfortable crimping any bullet that doesn't have a cannelure. However, I recently tried the Lee FCD in my LR260 when doing a load development with 123 Amax and Varget. The results were great. My next loading I forgot to crimp again because I never do it in my regular loading steps. The groups were definitely worse.
I have put a ( PROPER ) Lee FC on a bullet and then pulled the bullet to see if there was any visible deformation, I couldn't tell at all by my eyes. I'm sure one could go overboard on a crimp by setting the die up wrong and deform a bullet but the die is pretty easy to set up correctly.

I'd say its worth a try.

I'm certainly considering giving it a shot. I shoot mostly factory rifles so anything I can do to improve accuracy and consistency I am always willing to consider.

The dies are not expensive and it only takes a few seconds to add one more step and the way I have things set up now using the Hornady Case Prep center (caught one cheap on Ebay from an estate sale) I have things running very efficiently now and I'm putting less time into loading than I ever had before in the past.

 

[HARPERC]

Prevents setback on the rounds in a magazine due to recoil impact.

Kind of useful, but not absolutely necessary.

 

[catamountsierra]

I have put a ( PROPER ) Lee FC on a bullet and then pulled the bullet to see if there was any visible deformation, I couldn't tell at all by my eyes. I'm sure one could go overboard on a crimp by setting the die up wrong and deform a bullet but the die is pretty easy to set up correctly. .

I noticed that getting a proper crimp may require adjustments if you change bullets. I crimped a bunch of 62gr Scirroco II bullets for my 223 and could barely get a crimp visible in the brass and no visible crimp in the bullet. I then crimped a couple of 55gr NBTs without adjusting the die. The result was an easily visible crimp at least as deep as most cannelures even though those bullets didn't have one. That was what convinced me that the best crimp was just a very light one.

 

[benchracer]

I recently started experimenting with 208 AMAX's from my M1 Garand. I had loaded up some dummy rounds to try to determine a good OAL for feed reliability. Most folks seem to discuss crimping as a solution for bullet setback, among other things. I experienced problems with the bullets moving FORWARD in the case upon being fed and chambered.

That is what caused me to consider using the LEE factory crimp die. I haven't gone further with testing, yet, so I don't know if it will solve my problem or do anything for accuracy. It has, however, prompted me to consider some things to which I hadn't previously given much thought.

Up to this point, I have mostly loaded for bolt action or single shot rifles. When I have loaded for semi-autos, I didn't do so with precision in mind. Now, I am trying to figure out how to load precision ammo for semi-autos. At this point, I have more questions than answers, but it seems to me that a carefully executed crimp COULD be beneficial in this application.

Aside from that, I had been planning a Cape Buffalo hunt in Zambia. I was going to take my 375 H&H loaded with 300 grain Swift A-Frames, loaded to book length and crimped. It seemed like a good idea to err on the side of reliability for that purpose.

Aside from special applications, I have never felt the need to crimp. Maybe my current experiments will teach me something that changes my way of thinking...