To crimp or not to crimp?

Dultimatpredator

Dultimatpredator

Well-known member
I am working up some loads for my new Remington 7600 chambered in 35 Rem and am questioning crimping the loads. I have owned three or four of these rifles in the past chambered in 30-06 and 243 and have used factory loaded core locts in the past and my own hand loads. Crimping is best for? Lever action or semi auto rifles where casings could get bumped or jarred from recoil..correct. I assume I don't need to crimp. I tried crimping in the past on some 44mag load and found that it shrinks the overall size. This has to affect consistency and accuracy in load when not done properly and consistently doesn't it?
 
For rough handling, tube magazines, heavy recoil, ect. crimping can sometimes be an advantage. When I do crimp I use the Lee Factory Crimp Die. That's the best tool that has ever left the Lee factory!
 
Good advice from GC. I've been loading for 45 years now and other than revolver loads have never crimped for a bolt gun. Unless your shooting something with a tube magazine I wouldn't crimp.
 
Quote:
I never planed on crimping but wanted some advise on why crimping is needed. Thanks guys.



Dultimatpredator,

Beyond the obvious reasons(i.e tube feed mags, heavy recoil,
etc), there comes piece of mind. Here is my take on
crimping, and when I say crimping, I mean crimping with a
Lee Factory Crimp die, not crimping with a seating die. I
crimp my hunting ammo, whether it goes in a bolt gun, a pump
gun, or an auto-loader. For these firearms, I am constantly
loading and unloading them, through the course of hunting
activities, and I don't want bullets moving into the cases.
When I put a light crimp on the loads, I have not found
a bullet that has moved in the case, through normal handling
in these hunting activities. I have had bullets move into
case necks, when they were not crimped.

As for accuracy loss due to crimping, done correctly,
there is some evidence that it can be a slight improvement
in accuracy /ubbthreads/images/graemlins/shocked.gif On the site AccurateReloading.com,
an international shooter did some testing of crimped(Lee
Factory Crimping Die) 308 Win loads, versus uncrimped
308 Win loads. And actually measured a slight improvement
in accuracy in the crimped loads. /ubbthreads/images/graemlins/grinning-smiley-003.gif I believe the
speculation as to why, centered around more consistent
neck tension. I know on my bench, the crimped versus
uncrimped loads show very little difference. Some tests
show slight improvements, with crimped loads, and some tests
show slightly larger groups with crimped loads, and some
showed no difference. So for big game, and predator,
hunting ammo, I crimp. For colony varmint, or paper
punching ammo, I don't crimp, unless I suspect it may
help groups, and in a couple of bullet/brass combinations,
it has.

One final point to be made on crimping, is heavy crimping,
is not what I am referring to here. I use Lee Factory
Crimping dies, non-cannelure bullets, and a VERY light
crimping force. Basically just enough force to put a slight
mark on the case mouth. If I use anything more than a
very light crimping force, I have observed some load/bullet
combinations average group size opening up.

Squeeze
 
Glad to see another long time reloader here, IDBob.
I started loading in 1948 when I was 14, and only crimp 30-30 rounds for my son's Marlin 336. Plus, I have been experimenting with crimping 22 Hornet loads to shrink the groups. The jury is still out on that though.
No reason to crimp any other loads. I shot centerfire benchrst competetively, and no one crimps loads in that game.

Martyn
 
Quote:
Glad to see another long time reloader here, IDBob.
I started loading in 1948 when I was 14, and only crimp 30-30 rounds for my son's Marlin 336. Plus, I have been experimenting with crimping 22 Hornet loads to shrink the groups. The jury is still out on that though.
No reason to crimp any other loads. I shot centerfire benchrst competetively, and no one crimps loads in that game.

Martyn



I did the same thing, Shot bench rest with a 222 on a solid bottom mauser action. Did real well til the sleeved actions came along and put me out of competition. The 222 got restocked and spent many years killing ground squirrels afterwards.

I started loading in the early 60's and there's not a gun in the safe that does over an inch at a hundred. The new CZ Varmint does dime sized groups and none of the bolt guns have ever had a crimped round thru them. Never had a bullet slip back into a case no matter how much handling.

I use the Lee collet dies for the varmint rounds and those do have a learning curve to get the right neck tension.
 
I have only crimped 44 mag shells of which I have never fired. I tried to duplicate what factory crimping looked like but remeasured my bullets and found inconsistancies in overall size afer this was done. Any advise on properly crimping? When is much to much? I own a 336 in 35 Rem as well which I know is going to need crimping done on its ammo.
 
With crimping do you use a practice shell and keep adjusting the crimp and keep measuring it untill it starts changing the overall length and than backing it off a hair, or is there a theory to this. I use RCBS dies and have to reset them every time I crimp a new set of reloads and it would be almost impossible to get the exact crimp every time throughing off the consistancy, correct? How much crimp do I need to use on an average rifle bullet and how do I keep the crimp consistant?
 
I only crimp with the Lee FCD, so that's not an issue, love it for crimping, so much I even made one for my 405 Winchester from a 416 Remington FCD. Crimping with a seating die is a pain in the butt in my experience.

Tim
 
Quote:
With crimping do you use a practice shell and keep adjusting the crimp and keep measuring it untill it starts changing the overall length and than backing it off a hair, or is there a theory to this. I use RCBS dies and have to reset them every time I crimp a new set of reloads and it would be almost impossible to get the exact crimp every time throughing off the consistancy, correct? How much crimp do I need to use on an average rifle bullet and how do I keep the crimp consistant?



Dultimatpredator,

At the risk of being a smart (|), getting consistent crimps
from a seating die, like your RCBS, is almost impossible,
unless you are meticulous about trimming, and use an
accurate trimmer. That is why the Lee Factory Crimp Die was
specifically called out. The study I mentioned, also
specifically calls out that crimping die. If you are
considering crimping, get the LFCD. They are cheap.
DO NOT CRIMP WITH THE SEATING DIE!

Squeeze
 
How dose the crimp die work? I do trim casings after every shot in needed. Dose the Lee die automaticaly measure from the trimmed size? Or dose it get lowered till it hits the shell? How dose it work?
 
there are alot of different schools of thought on crimping
like you said to keep the bullets in place and to keep pressures the same but I have never found a significant difference in it one way or another
Try it and see though you may like the results
 
The 7600 should not require crimped loads since it feeds from a clip. Standard FL dies give enough bullet tension to hold even the short neck magnums. If you feel you need to crimp, a three die set or separate crimping die would work for you. Repeatable crimps are hard to get without controlling the shell length. I have not tried the Lee FCD but it has a good following of experienced reloaders.

The .44 Magnum needs a good solid crimp to hold the bullet and to develop consistant presures, especially in near max loads. Here again you want a three die set and consistant shell length to get consistant crimps. Using the same type or brand of shell cases will help you get more uniform crimps and accurate loads. Variations in case wall thickness can affect the crimp as well. I don't like seating and crimping with the same die. Only crimp on a cannelure or crimping groove or your going to distort the bullet and/or affect the overall length. The bullet style and how the seating punch engages it can affect the overall length somewhat. As long as the crimp lands on nearly the same place on the cannelure of each bullet there should be no problems.
 
Thanks, I ordered one from Cabelas, still cheaper on shipping after paying taxes than Midsouth. It was $18.97 at Midsouth VS $13.97 at Cabelas. I had almost four bucks worth of club points I used on the purchase as well so it was around $10 shipped. Can someone explain to me how to set up this die for proper crimping. I don't plan on using this for my 7600 only my 336 unless I get good at it then I will use it for both since tests have shown tighter grouping with proper crimping. The picture of Lee crimp die looks a little different with Cabelas offering but I'm sure its this same one. This die is universal and will fit in my RCBS re loader wont it?
 
All Current production Lee dies are 7/8"-14 threaded, same as RCBS. The FCD comes with instructions, you just thread the die in until it touches the shell holder when the ram is all the way up, lower the ram and give a ½ turn more, and tighten the lock ring, that will give you a light to moderate crimp, you can increase the crimp up until the collet pieces come together for a max crimp.

Tim
 


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