Question about reloading dies for a 7 mm rem mag

[vahena]

Hello everyone,
New to reloading and I came across a reloading die with 3 dies in the set, my question is, there is a crimp die, is it better to or more accurate to crimp a bullet, or does crimping a bullet add to accuracy?

 

[gohring3006]

I personally don't crimp any long range bullet I used to crimp some bullets with canelures but I found my groups suffered at extended range so I just get enough neck tension and never crimp but that's just with the 3006 I never had anything any bigger some of the other guys might have other opinions on larger higher recoiling calibers I have never had any bullet shifts in my magazine even with 200gr bullets

 

[Engineering101]

As was stated a crimp will not aid accuracy but it will keep the recoil from moving the bullets around in the cases. I never crimp any rifle loads (I do pistol) but also don't have anything that kicks much past 20 ft lbs. The crimper is usually located in the bullet seating die and getting it to crimp is a matter of adjustment.

 

[vahena]

As was stated a crimp will not aid accuracy but it will keep the recoil from moving the bullets around in the cases. I never crimp any rifle loads (I do pistol) but also don't have anything that kicks much past 20 ft lbs. The crimper is usually located in the bullet seating die and getting it to crimp is a matter of adjustment.

OK, I think I understand movement in the case from recoil and the bullet adjusting themselves. I read somewhere that it allowed the charge to come to full bore before the bullet was pushed out, could that be true?
Also if the crimp is for holding the bullet in its place better in the case, what pistol cartridge should I be crimping, 44 mag and up ? I noticed my 45 acp and 44 mag cartridges are not crimped.

 

[gohring3006]

they say that crimping could aid in velocity because it allows the pressure to come to full potential like you said but I don't believe it I have noticed no significant change in velocity but I have noticed tighter groups by not crimping I have no experience in handguns but if you are shooting factory loads in handgun they will have a crimp but I could be wrong about that my father in law would know that answer but I think that most factory handgun might be crimped

 

[Engineering101]

vahena

Now you have opened a can of worms mentioning the 45 ACP and 44 Mag. There are two different types of crimps used for pistol ammo. The taper crimp is typically used for automatics like the 45 ACP and the roll crimp (more easily seen) for revolvers like the 44 Mag. I've never seen any factory pistol ammo that wasn't crimped. You can't roll crimp a 45 ACP and the like because they headspace off the mouth of the case. I'm sure wikapedia or some such could give you the full story on this.

 

[vahena]

vahena

Now you have opened a can of worms mentioning the 45 ACP and 44 Mag. There are two different types of crimps used for pistol ammo. The taper crimp is typically used for automatics like the 45 ACP and the roll crimp (more easily seen) for revolvers like the 44 Mag. I've never seen any factory pistol ammo that wasn't crimped. You can't roll crimp a 45 ACP and the like because they headspace off the mouth of the case. I'm sure wikapedia or some such could give you the full story on this.

Sorry, I never meant to open up acan of worms.
So I guess I got my answer on the crimping of my 7 mm mag, I dont need to crimp them,but what about the 45 acp and the 44 mag in which I will be loading soon also.I have checked my 45s factory bulk supply and the are not crimped, I didnt have a chance to look at the 44 mag factory shells, Why would they have to be crimped? is it because of the recoil?

I do have a question about not crimping the 7 mm rem mag, if not crimped would the bullet leave the cartridge before all the power had time to build up presure in the case, and leave power flash in the barrel , because the bullet left to soon? I hope I am explaining this right.

I want to thank everyone who has responded as I want to do this right and safe, also want accuracy, the main reason I am starting reloading .
Maybe this thread is getting to complicated with all the different loads we are talking about crimping. I mainly want to know about my 7 mm mag as that is going to be my long range rifle and I am looking for 1 ragged hole.
The pistol ammo, maybe should be another thread?

 

[gohring3006]

I wouldn't crimp any longrange rifle ammo especially if I was beginning to reload till I got good with practice I mess a bunch of brass and bullets when I first started crimping just to find out that it wasn't as accurate any way you could potentially over crimp and create more pressure than you want so in my opinion you as a beginner I wouldn't crimp any rifle ammo but I think you should crimp all pistol ammo

 

[vahena]

I just checked my 44 mag cartridges and they were crimped but not the 45 acps both being factory bulk ammo. I also checked my factory 7 mm rem mag ammo and they were not crimped.
Are you saying to crimp the 45 acps as well?

 

[gohring3006]

I not the one to ask on pistols but know that it head spaces on the case rim so its a different type of crimp as the other gentlemen posted the one that said "open up a can of worms" I'm not sure who that was I'm replying on my phone

 

[g0rd0]

for pistol ammo Lee sells a factory crimp die. Since I first started using Lee factory crimp dies for my 9mm, 357 and 44 mag I have not had any feeding problems at all.
So, I bought a lee factory crimp die for my 7mm rm and found it to be a huge waste of time. I went back to not crimping. Crimping did not effect my accuracy but, did not help it either. IMHO dont bother

 

[vahena]

for pistol ammo Lee sells a factory crimp die. Since I first started using Lee factory crimp dies for my 9mm, 357 and 44 mag I have not had any feeding problems at all.
So, I bought a lee factory crimp die for my 7mm rm and found it to be a huge waste of time. I went back to not crimping. Crimping did not effect my accuracy but, did not help it either. IMHO dont bother

Thats great, I just bought 3 sets of Lee dies, 45 acp and 44 mag both sets come with thier own crimp die. And a 4 die set for the 7 mm rem mag, I guess I won't be needing the crimp die in that set.
That is what is so good about this site, everyone is happy to help and chime in with a lot of different views,

I want to thank everyone who has replied, again thanks

 

[Buckinrut25]

I have been loading 7mm RM for a very long time and have never found the crimp to be nessasary for my bolt guns. If I were running some sort of auto loader I would. It just comes down to your use of the firearm. I run the 162 Hornady SST pretty hot and have never had an issue with rounds changing COL on me with high recoil. My basic rule of thumb is to crimp all autoloaders and just use neck tension on the rest. I hope this helps. Also I have tested to see if crimping changed velocity and I found a small improvement in speed but at the cost of a larger Standard Deviation.

 

[Ol'Gator]

Maybe a little misunderstanding when talking crimping 45 ACP. Crimp die is used it to return the mouth back to normal shape after it had been expanded earlier to accept the bullet without shaving. The crimp does not aid in "holding" the bullet.