Crimp groove or no?

[Blackwater]

If you were designing a cast bullet for a bolt gun in '06, .303 Brit or 7.62 Russian, would you include a crimp groove or just let case neck tension hold the bullet?

[felix]

Neck tension because it better handles ignition with slow powders. Lighter neck tension works better with smaller bore calibers, assuming no ammo in magazine style of shooting. ... felix

[David R]

I never crimp rifle. Even if I did, the groove ends up in the wrong place.

For me a crimp is not needed.

Taper crimp 45 ACP
Roll crimp 44 mag and 45 colt.

David

[Blackwater]

Felix, I want to keep the magazine loaded, and sort'a plan on using midrange loads in the .303, 7.62x54, '06 and Whelen. I crimp all .45/70's except for my BPCR, which is a single shot. Even crimp with the #3 Ruger. Just think it helps get better ignition crimped when using smokeless, but haven't honestly tried it non-crimped in the #3, so don't really know.

[1Shirt]

Just for what ever it is worth, I use a lee factory crimp on every case I load w/cast. Have not comparied all of the cast loads for accuracy between uncrimped and lee factory crimp, but of the half dozen or more that I have checked, all grouped a little bit better for me. Think it is either the consistancy of the crimp, or possibly just a little bit of plain dumb luck.
1Shirt :coffeecom

[SharpsShooter]

I'd go with neck tension. Consistency with crimp relies critically on case length for even application. Even a few thousand's of an inch difference will increase or decrease the crimp tension and would result in load variations.

[StarMetal]

I'd go with neck tension. Consistency with crimp relies critically on case length for even application. Even a few thousand's of an inch difference will increase or decrease the crimp tension and would result in load variations.

None of that applies when you use a Lee factory crimper, it doesn't rely any at all on case lenght.

Joe

[felix]

Joe, please define the Lee factory crimper. I don't have one. ... felix

[Scrounger]

Joe, please define the Lee factory crimper. I don't have one. ... felix

Felix, if I can jump in front of Joe for a minute here, it is a collet crimper, works the same way their collet sizer works. The farther (deeper) you turn the die in, the smaller the collet closes.

[SharpsShooter]

Felix, if I can jump in front of Joe for a minute here, it is a collet crimper, works the same way their collet sizer works. The farther (deeper) you turn the die in, the smaller the collet closes.


Scrounger, ya answered my question before could type it. :D

Starmetal,

In the case of a collet die, case length wouldn't be perhaps as critical, but a longer case would get more of a squeeze and a resultantly tighter crimp, and a short one would get a bit less. Thats if I undertstand correctly.

:coffeecom

[StarMetal]

Let me say that if your cases are that long they may not chamber. Let's not be critical and nit picky here. You don't have to have the cases all the exact same lenght down to .0000001 with Lee collet factory crimper.

Felix

Like Art said it's a collet crimper, crimps in four places around the case mouth. Will even crimp non cannelured jacketed. The crimping motion comes in 90 degrees from the side after the case has stopped moving up, thus no wrinkled necks or buckled cases.

Joe

[felix]

Sounds like an adjustable "total" crimper, then. No flies on that! Whenever I do a crimp, I crimp by feel so that each case gets the same force treatment. In other words, the die is set for max crimp that could possibly be used, and the tool arm is moved just enough for the same crimp feel. ... felix

[felix]

OK, that's different than what I thought via Scrounger. I was thinking more in terms of an adjustable taper crimper which would be really ideal. That kind of crimp would help alignment (straight walled cases). ... felix

[StarMetal]

It's basically as Lee describes, a Factory crimp, very very much like factory crimped ammo.

It doesn't crimp the whole neck in, only four spots around very near the mouth of the case, like a military or like I said Factory crimp. Not at all like a taper crimp.


Joe

[canuck4570]

I use a Lyman taper crimp for my 4570 and it works good I think it put a even pressure around the cast bullet ... I mesure just below the mouth belling I did tu sit the bullet and whatever it is I adjust the taper crimp down until the mouth of the catrige measure the same....the Lee factary crimp I notice sort of leave a small ring around the case mouth after firing...and even after resizing seems not to disapere.....

[Bman]

Haven't used my FCD much with cast yet but I did have a '94 in 30-30 with a wicked strong magazine spring that would push factory Rems into the case. That did not happen with my reloads using the Lee die. Oh one more thing about the Lee die once the collet closes all the way the crimp doesn't get any tighter so within the variables of case neck thickness, actual bullet diameter etc. it gives a very repeatable crimp.

[StarMetal]

Lee just recently come out with the Factory Crimp die for the 30 Luger and now that's a blessing as that's a very hard round to crimp . If any of you load it you will know, the 7.62x25 Tokarev too.

Joe

[sundog]

Felix, I have several factory crimp dies. Next time we getogather I show you. Quite ingenious, and for some applications works extremely well!

Not too long ago I was disatisfied with crimp I was getting on some straight wall pissola ammo, .357 and .44 Mag mainly, so I got a couple of taper crimp dies and have been very happy with the results. Boolit seating and taper crimp in separate operations and the ammo looks and shoots real good. sundog

[Char-Gar]

If you are designing a bullet that might be used in a tubular magazine someday, put a crimp groove in it. If not, then firgit the crimp groove.