Crimp on heavy magnums

[69daytona]

I just picked up a Rem 700P in 300 RUM( its at the shop getting a muzzle brake and trigger job)
I do all my own reloading and have for 30years since I was a private in the USMC, anyhow this is my first magnum and I would like to know what typw of crimp you guys use and what tool do you use to do it with, I want to keep my SD as low as possible.
I use a Lee factory crimp die for my .308s and .223 with great results but not sure on this one. any help would be welcome.

 

[Victor N TN]

Re: Crimp on heavy magnums

For best results use bullets that have a "canalure" or crimp groove. A Lee crimp die will be good to get you started. Just be sure to get the case mouth right on the length so it gets a good bite on the crimp groove of the bullet. Don't put so big a crimp on the case mouth that it bulges out the case neck.

I had problems with my first crimped rifle cases. I crimped it so hard that it bulged out the case neck and didn't want to chamber correctly.

Oh well... You usually get experience in these matters just after you need it.

 

[John Adams]

Re: Crimp on heavy magnums

I shot 300 Winchester mag for years and never crimped.

 

[steve123]

Re: Crimp on heavy magnums

Use a neck bushing die with as much tension as you feel you need.

Crimps are for pistols rounds.

Steve

 

[69daytona]

Re: Crimp on heavy magnums

If you have never tried crimping your handloads you should try it. All factory loads are crimped, most use a taper crimp so it not that noticeable, it does cut down on your SD and on rifles that will hold more than one at a time, exspecially on heavy recoiling magnums you will get bullet set back which can change your bullets trajectory.
If you only shoot one at a time its no problem. I shoot a lot of heavy loads from my 2 S&W 500s(400-600gr bullets at up to 1600fps on the 600s) and if you dont crimp they will walk out and jam the revolver.
I have even noticed this on my .308s in my M1A but in a magazine they get forced back into the case.

 

[Bacarrat]

Re: Crimp on heavy magnums

Most of use rather not work the brass that much. With the correct neck tension, you will not get bullet setback. Factory ammo is crimped for a variety of reason, and I do not believe it's for accuracy either.

Only thing I crimp are my pistol rounds.

 

[Downzero]

Re: Crimp on heavy magnums

Bolt action ammo should not be crimped.

 

[Victor N TN]

Re: Crimp on heavy magnums

If the bullet you like doesn't come with a canalure / crimp groove, you can buy a neat little hand operated machine to do it.

 

[our gang]

Re: Crimp on heavy magnums

There is no need to crimp a 300 RUM as the bullet weight inertia (unless you go to 250 Woodleighs) will not pull the bullet. The Lee crimp dies are excellent and work just fine in all rifles. Anyone who thinks you DON'T need to crimp a 400/416/458/500/505/577/585/600 bolt or double rifle better not be planning on hunting animals that bite back.

 

[69daytona]

Re: Crimp on heavy magnums

I use a lee crimp die on my .308s just to keep velocities very close and standard deviation down to single digits it works great.

 

[Coyotejunki]

Re: Crimp on heavy magnums

I never crimp my rifle ammo, maybe I should try it on some test loads.

 

[BOLTRIPPER]

Re: Crimp on heavy magnums

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Downzero</div><div class="ubbcode-body">Bolt action ammo should not be crimped.</div></div>



this should be chiseled in stone....

however...you prolly need more cowbell !

 

[Grumulkin]

Re: Crimp on heavy magnums

I've tried crimping and not crimping and I wasn't able to tell a bit of difference in accuracy.

 

[Downzero]

Re: Crimp on heavy magnums

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Grumulkin</div><div class="ubbcode-body">I've tried crimping and not crimping and I wasn't able to tell a bit of difference in accuracy.
</div></div>

So that should signify that crimping is an unnecessary step.

 

[our gang]

Re: Crimp on heavy magnums

I repeat: There is an absolute need to crimp hard recoiling rifles that shoot large diameter heavy bullets. The guys at Holland & Holland, Rigby and Purdey have forgotton more about large bore ammo than we will ever know.
It is also necessary in heavy recoiling revolvers and big boomer tubular magazine lever guns.
I suggest you load up a S&W 329 with max loads of H110 and 300 gr hardcasts OR a 450 Alaskan built on an 71 WRA action with 450 gr bullets OR a Rigby 600 Nitro double rifle with no crimp and see what happens.
There is a reason bullets for these guns have crimping grooves and it a'int for looks!
IME the Lee crimp system improves accuracy in some .224-.308 rifles and does nothing in others. Anything bigger always gets crimped as it has no effect on real world hunting accuracy and ensures you won't be sitting there with a rifle tied up because a bullet slid forward and tied up the gun or dumped all the powder into the action. That can really increase the pucker factor if a Buff or Brown has you in his crosshairs.
Also interesting to note that all military ammo (except for handgun that headspaces on the case end) in crimped and frequently sealed as well. Once you start shooting at things that bite or shoot back, reliable function is a terrible thing to waste trying to get 1/4 moa better groups.

 

[Grumulkin]

Re: Crimp on heavy magnums

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mr. Humble</div><div class="ubbcode-body">I repeat: There is an absolute need to crimp hard recoiling rifles that shoot large diameter heavy bullets...Once you start shooting at things that bite or shoot back, reliable function is a terrible thing to waste trying to get 1/4 moa better groups.</div></div>

Well, I crimp loads for my bolt action 458 Lott because I've assumed recoil might cause bullet migration but I've never tried it without a crimp so I'm not sure if that would happen. Ditto, loads for a 300 Weatherby bolt rifle.

So I would ask, have you tried loads in heavy recoiling rifles without a crimp? If you haven't, what you have said is an untested theory.

I do know, uncrimped bullets in a 500 S&W Magnum will move out of the cases if fired in a revolver from unfortunate experience.

 

[our gang]

Re: Crimp on heavy magnums

The only big boomers I shoot w/o crimps are single shots. I assume the guys who make big bore repeating or double rifles and the ammo for them probably have a tad more experience than I do, so I'll accept their wisdom. You might get away with it in the Lott, depending on neck tension, bullet weight and rifle weight but why tempt fate? The slight loss in case life is no reason to risk a tied up rifle in a potentially fatal situation.

 

[69daytona]

Re: Crimp on heavy magnums

Thanks Mr. Humble. I do plan on using the Lee crimp die on my 300 rum when it comes back from the shop. I was just down looking at different factory ammo and all of it was crimped, either a taper crimp or roll crimp but it was all crimped.
I crimp all my 500s because my 44 had some walk out on my once but not enough to lock anything up. try a S&W 500 with 600gr GCFP at 1600FPS and you will change your mind on crimping heavy loads.

 

[CoCaDoRi]

Re: Crimp on heavy magnums

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mr. Humble</div><div class="ubbcode-body">I repeat: There is an absolute need to crimp hard recoiling rifles that shoot large diameter heavy bullets. The guys at Holland & Holland, Rigby and Purdey have forgotton more about large bore ammo than we will ever know.
It is also necessary in heavy recoiling revolvers and big boomer tubular magazine lever guns.
I suggest you load up a S&W 329 with max loads of H110 and 300 gr hardcasts OR a 450 Alaskan built on an 71 WRA action with 450 gr bullets OR a Rigby 600 Nitro double rifle with no crimp and see what happens.
There is a reason bullets for these guns have crimping grooves and it a'int for looks!
IME the Lee crimp system improves accuracy in some .224-.308 rifles and does nothing in others. Anything bigger always gets crimped as it has no effect on real world hunting accuracy and ensures you won't be sitting there with a rifle tied up because a bullet slid forward and tied up the gun or dumped all the powder into the action. That can really increase the pucker factor if a Buff or Brown has you in his crosshairs.
Also interesting to note that all military ammo (except for handgun that headspaces on the case end) in crimped and frequently sealed as well. Once you start shooting at things that bite or shoot back, reliable function is a terrible thing to waste trying to get 1/4 moa better groups. </div></div>

Keep things on track, wow... Last I checked it was crimping for a 300rum.

Have one, hunted with one, burned a barrel out on one. I NEVER crimped as there is no need to. You are even getting a break put on. Crimping is a non issue here and load for the best accuracy and roll with it...