crimp or not
- Thread starter dalestu
- Start date
I've never crimped for my M1 or M14. Never had any issues. Depends on how hot the load is and, to a certain extent, the quality of his brass, though. neck tension should be enough.
You'll have to work up the load just like you did for your bolt action.
You'll have to work up the load just like you did for your bolt action.
- Location
- Somewhere on the Hudson Bay Coast
I crimp any time I load with a cannelured bullet. The crimp uniforms bullet pull, similar as does minimizing the bullet jump to the rifling. This results in better accuracy, while allowing you to cycle the rounds through the magazine without functioning problems that sometimes occurs withy bullets seated long. On the negative side, you may or may not observe any difference in accuracy, and it is another step to perform. Crimping in the same step as bullet seating leaves something to be desired. It is unlikely that with bullet weights normally loaded in a .300 that set back due to recoil would occur. If you do decide to crimp, the Lee Factory Crimp Die makes a nice uniform job of it.
blacksmithden
CGN Ultra frequent flyer
I always crimped my 300 win mag stuff. I goofed once and got an unsized case from another gun jammed in my breach. The extractor wouldn't pull it out. We took a cleaning rod and put the female threaded end down the barrel until I felt it go over the tip of the bullet.....then hammered it out. I'm sure glad I crimped that round. It was nice peace of mind knowing that I wasn't driving a bullet down onto the powder and primer. It probably wouldn't have gone off even if it was going down on top of the powder...but just the same.....Now, that being said.......the debate over whether to crimp or not to crimp has been going on since crimp dies were invented. If you've got the die, use it. You paid for it, so even if crimping isn't worth it, you can justify in your own mind that it was a good purchase and that it's not just sitting on the shelf doing nothing 
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About a year ago I got interested if crimping could produce any difference in speed or accuracy. So I loaded 20 identical cartridges (52.0 IMR4895 150 Nosler BT 30-06) and crimped half of them with Lee Factory Crimp die. No difference was found neither in average speed, nor in speed dispersion.
But when I repeated the same experience with half-loads (20.0 IMR SR 4759 under Hornady 100 half-jackets) the difference was very visible. The crimped cartridges showed higher speed and better consistency.
But when I repeated the same experience with half-loads (20.0 IMR SR 4759 under Hornady 100 half-jackets) the difference was very visible. The crimped cartridges showed higher speed and better consistency.
Only things I crimp are revolver rounds and anything for a lever action rifle with a tubular magazine. For 40+ years, I have loaded all manner of cartridges without crimping never experienced any negative effects. Regards, Eagleye
- Location
- Somewhere on the Hudson Bay Coast
Try crimping with the RCBS dies and see if you are satisfied with the results. The method I have resorted to is to thread the seater stem to the top of its adjustment so it cannot touch the bullet, then run the loaded round up to the top of the ram, and thread the seating die in until refusal. I only use my thumb and two fingers to accomplish this to prevent over crimping. After your cartridge is crimped, back off the die a turn or two and repeat for the subsequent cartridges. It can leave your fingers sore if you are crimping a large number of rounds, but thus far I have found this method gives the best uniformity when crimping with a conventional seating die.
If you do decide on the Lee crimp die, it won't break the bank. I had to get one for my .308 because my Redding comp die set doesn't crimp, and I am quite happy with it.
- Location
- Somewhere on the Hudson Bay Coast
Sometime ago I switched to the Lee Factory Crimp Die for my handgun loads because it solved any chambering issues with revolver loads that occasionally showed up. I was sold on the first try. Lee has some really good ideas, but they have had a few not so great ideas too.
The Factory Crimp Die for rifles is almost as good, but they are cartridge specific. I expected I might be able to crimp any .30 caliber cartridge with this die, but that is not the case. The way this thing works is that the shell holder must contact the base of the die to close the crimping collet, so the cartridge must be the correct length.
The Factory Crimp Die for rifles is almost as good, but they are cartridge specific. I expected I might be able to crimp any .30 caliber cartridge with this die, but that is not the case. The way this thing works is that the shell holder must contact the base of the die to close the crimping collet, so the cartridge must be the correct length.
Crimping separately i.e. not with the seater die is faster and easier. It's probably more consistent too. I crimp all my hunting ammo with a Lee FCD - brass length is less critical, no cannelure needed on the bullet, and whether it's true or not I think it's helping accuracy from a more consistent bullet pull weight. I believe it's true, so if I crimp and it's real accurate I'll keep doing exactly the same thing every time. FCD's are cheap and pretty well fool-proof.
