To Crimp or not to crimp....

Blaine · Member Joined: Feb 24, 2005 Posts: 260 Location: Maine

I was wondering how many of you folks crimp your rifle handloads. (1) If you crimp, what tool do you use (i.e. if separate from the bullet seating die) (2) Do you always crimp for accuracy reasons, or only for autoloaders and tube mags (3) Do you crimp (taper) even when there is no channelure? (4) Do you think crimping has any effect on accuracy? There, how's that for a lot of rambling questions? Rolling Eyes

Blaine

Gil Martin · Posted: Wed May 18, 2005 2:51 pm Post subject: Re: To Crimp or not to crimp....

It depends. Normally for rounds in bolt actions like the .270, .280, .30-06 and 8mm Mauser, no crimps are required. For lever action cartridges such as .30/30, .35 Rem, .444 Marlin and .45/70 I use the roll crimp feature of the seating die. I would prefer a taper crimp, but do not have a tool to accomplish it on these rounds. I have not noticed any significant difference in accuracy with crimped versus uncrimped rounds. All the best...
Gil

Blaine · Member Joined: Feb 24, 2005 Posts: 260 Location: Maine

I believe that crimping has the same effect as setting the bullet out almost touching the lands. In other words, it lets the cartridge build up pressure before releasing the bullet. So, if you can seat the bullet out so that you get consistent release(i.e. pressure) then no crimp would be needed. However, on those loads where the bullet is just too short to set out at the rounds, would crimping produce the consistent pressure needed for accuracy? I'm just wondering what other guys do. Thanks for the input, Gill.

Blaine

DallanC · Site Admin Joined: Jan 18, 2005 Posts: 3572 Location: Utah

I do not crimp. I dont own a rifle that requires it so its one less hassle to worry about.

-DallanC

longwalker · Posted: Thu May 19, 2005 8:25 am Post subject: Re: To Crimp or not to crimp....

Blaine,

I only crimp on semi automatic pistol, and revolver loads. Bullets I use in my 25-06 and 338-06 do not have a crimp cannelure, therefore I do not crimp. My understanding is, if you crimp with a bullet with no cannelure you can dammage the bullet. One would wonder how bad it could be damaged, but sometimes a little change can have a big effect.

longwalker

Blaine · Member Joined: Feb 24, 2005 Posts: 260 Location: Maine

Longwalker, according to Lee Precision using a taper crimp doesn't hurt the bullet and in fact (they say that) the tapered crimp on the case keeps the bullet heel straighter as it leaves the case. That sounds to me like a bit of a stretch. Of course they are trying to sell their "Factory Crimp Die". The only thing that made a bit of sense to me was the idea that a consistent crimp would release the bullet at the same pressure and therefore same velocity. That is what I was wondering about and if anyone had had any empirical evidence of that. Thanks for the input guys.

Blaine

Flint54 · Posted: Fri May 20, 2005 1:47 am Post subject: Re: To Crimp or not to crimp....

I only crimp rifle rounds that require it for loading in lever guns. I crimp all revolver rounds as most are with loads that need crimping to assist in the burning of the powder, WW296 needs a good crimp for effective burning as do many of the powders on the slower end as are used in most magnum handgun cartridges. It also gives you a lower SD due to more efficient burning. I taper crimp all semi auto pistol rounds to prevent bullet setback on the loading cycle.

GroovyJack · Member Joined: May 21, 2005 Posts: 621 Location: Bama

I dont crimp . I have heard what u say about more consistent velocity with crimps than no crimps .. Have tried both ways across a chrony and couldnt tell enuff difference to bother .. The crimps had a lower SD than no crimps but not much difference ... Maybe 15 fps higher SD in my 'unscientific' tests ..
Jack

joe72204 · Rookie Member Joined: May 21, 2005 Posts: 1

I use my sizing die to crimp my 30-30`s and 45-70`s after removing the decapping pin.The sizing die is adusted to just crimp the brass into the canulure .I roll crimp all revolver rounds and taper crimp all semi-auto pistol rounds .

Take care

Pat

popgun · Posted: Mon May 23, 2005 11:59 pm Post subject: Re: To Crimp or not to crimp....

I crimp on some but not all that I reload for. I use the Lee Factory Crimp Die on 22 Hornet, 223 Rem, 270 Win, & 308 Win.
The 22 Hornet got me started with the Lee FCD. It shrank my groups from just over 1" @ 100 to just over .5" @ 100. I was impressed. The 223 and 308's that I load in my AR's and M1-A are crimped because they are magazine fed. The 270 is another experiment to see if it shrinks the groups and I don't have any shooting data yet.
I plan on buying a FCD for my 375 H&H because the rounds take a beating in the magazine and tend to seat themself deeper because of recoil if not crimped. I have been roll crimping but want to try the factory crimp.

Joel · Rookie Member Joined: Apr 25, 2005 Posts: 8

Hidey, boys--

Newbie here, and this is a pretty neat forum, with what seems like no shortage of wisdom and experience. Love to learn.

I'm coming out of a 10-year hiatus on reloading, and I'm blown away by what I almost hafta relearn, and by what I've forgotten...

I mighta missed it, but one aspect of crimping that I don't think was mentioned is recoil. If you've ever had a .30-30 bullet shoved into the case while in the tubular mag, and powder's going all over, you look at crimping a bit differently. Likewise with the brute, the .44 Mag--when one of those boys jumps the case and locks up the cylinder, the fun's just startin'...

A bolt gun might be more forgiving in a lite caliber, but Blaine, didn't I hear you talking about .300WinMag? Won't your subsequent rounds in the magazine be kissin' the front of the box pretty hard with each shot? Or is it a single shot? Or are you benchrest shooting/single loading?

Just my dos centavos
Somethin' to chew on...
Have Fun, Be Safe!
Joel

Blaine · Member Joined: Feb 24, 2005 Posts: 260 Location: Maine

Joel,
Regarding the 300 WinMag, I'm working up loads for now so I'm shooting one at a time from a bench. I don't own a tubular mag rifle, but I agree that a crimp should be used there and in handgun loads. I have a T/C Encore (single shot) with 243 and 308 barrels that I'm concentrating on now, so a crimp would be for purely accuracy concerns. Once I start loading hunting loads for the 300, I will certainly have to consider crimping, although I have heard of folks that don't with this caliber. That is why I'm trying to get as much feed back as I can. I also am loading for my 270, but I don't think recoil should bother the rounds in the mag. I have shot a lot of factory rounds through it that didn't appear to have a crimp (at least no channelure) with no problems.

Blaine

JayB · Posted: Sun May 29, 2005 4:09 am Post subject: Re: To Crimp or not to crimp....

I only load for 3 rounds, 22Hornet, 243 and 6.5 Swede. I started crimping with the Hornet, Lee factory crimp die, to try and regulate the starting pressure as I seat them deep enough to fit the magazine. It did not make a huge difference to the SD but it did tighten the groups to under an inch at 100yards. That is as good as I can shoot, the gun can do better. I shoot a lot of cast in my 243 and again use a light crimp on these just to tidy up my handywork with the case mouth flaring die. I could not say if this has improved accuracy but it certainly has not hurt it. I never have used one on the 6.5, but I suppose I should just for curiosity if nothing else.

John

Blaine · Member Joined: Feb 24, 2005 Posts: 260 Location: Maine

[quote="JayB"] It did not make a huge difference to the SD but it did tighten the groups to under an inch at 100 yards. [quote="JayB"]

Welcome to the forum JayB. What groups were you getting before crimping, i.e. how much did crimping improve your groups?

Blaine

JayB · Posted: Mon May 30, 2005 3:07 am Post subject: Re: To Crimp or not to crimp....

Blaine,

Before I started crimping the Hornet used to get real close to an inch, probably nearer 1 1/4" . The crimping got it down to under an inch, the best I managed was about 3/4". Now how much of this reduction is real and how much is sympathetic measuring on my part because I want the groups smaller, I dont know. The reduction was real, the amount may not be as much as I would have liked, but, in my view the crimping worked.

John