Help with crimp

[Dano4734]

I seem to be having a heck of a time getting a good crimp on nickle cases for the casull. Am i doing something wrong or what do you guys do my friends

[Unclenick]

Nickel cases are always somewhat more brittle and can also be a little more springy than plain brass. What crimp die are you using and how are you setting it up and how are you proceeding? What bullet are you using? Does it have a crimp cannelure or a crimp groove?

[Dano4734]

I am using a rock chucker press and penn bullets 340 grain hard cast. Rcb dies

[rc]

Sorry not reading other posts right now.

1. Are your cases consistent length/trimmed?
2. Are you using Roll Crimp?
3. Do bullets have a good cannelure?
4. You should be crimping enough to roll that case right into that cannelure.

[Dano4734]

Ahh that’s it not rolling enough to the cannelure

[Unclenick]

That's what I'd meant by asking your procedure: how the die was set up. If you follow the RCBS instructions, you will land where you want it.

[Dano4734]

Thank you

[Charlie98]

If you are having a problem getting a consistent roll crimp, you might consider seating the bullet and crimping the bullet in a separate step... even using the same die (just back the seat stem out a little to crimp.) I rarely seat and crimp in the same step anymore.

[robhic]

Not to hi-jack but what's the difference between a canellure and a crimp-groove? I always thought they were the same thing, like car and automobile.

[robhic]

If you are having a problem getting a consistent roll crimp, you might consider seating the bullet and crimping the bullet in a separate step... even using the same die (just back the seat stem out a little to crimp.)

Or for $15 + you could get a Lee Professional Crimp Die. Some like it (me) and some don't. But for around 15 bucks on eBay you can get one and see what a nice job, IMO, they can give you. It adds a 4th step but worthwhile.

[Unclenick]

Based on cannelure's root word, you would think a crimp groove and a cannelure (the root word is an old one meaning channel) would be the same thing. But where crimp groove applies only to bullets, cannelure is not limited to the bullet.

A crimp groove is an actual recess molded or rolled into a bullet that goes all around the bullet the way a lube groove does, except that it is usually a tapered profile to roughly match the shape of a crimped-over case mouth that would be turned into it.

A cannelure is a groove with a tiny gear-tooth-like pattern floor that is rolled into a jacketed bullet or into a case, as you sometimes see in revolver cartridges where it marks the original commercially loaded bullet base's location. The military also put one around the head of M852 match ammo back when the hollow point Sierra MatchKings were not approved for combat, thus to make it easy to see it was non-combat ammunition. The SAAMI glossary describes the cannelure's appearance as corrugated, which works, too:

Originally Posted by SAAMI

CANNELURE

1. A circumferential groove generally of corrugated appearance cut or impressed into a bullet or cartridge case
2. Sometimes used in reference to an extractor groove.

[robhic]

Uncle Nick, I gotta give you credit (and thanks!) because every time you answer a question I feel like I'm back in school! I feel I should be taking notes as you really explain stuff well. It IS appreciated.

[T. O'Heir]

"...what's the difference between..." Semantics. And spelling. Most people can spell 'crimp groove'. snicker. However, a crimp groove is usually deeper than a cannelure. And a cast bullet will usually have a groove. A jacketed will have a cannelure that's put on with a roller.
"...Nickel cases are..." The nickel plating has a tendency to flake off. Plated case mouths seem to work harden faster too.
A cast bullet won't be driven as fast as a jacketed bullet so the crimping doesn't need to be as much as that on a jacketed bullet. In any case, the crimp should be just enough to hold the bullet in place under recoil and no more.

[45Colt_Man]

I use Lee Factory Crimp Dies on all my calibers.
Titan Reloading has the FCD for $18.49 plus shipping.
They also have the Collet Crimp Die which they claim is superior in crimp hold for $12.18 plus shipping.

Good luck to you. Dana

[Unclenick]

45Colt Man,

Unfortunately, they don't make the Collet Style Crimp Die for the Casull. Only for 45 Colt. I suppose you could turn a 0.098" spacer ring so the longer case would activate the shorter die, but you need a lathe or to know someone who has one who is willing to do it for you.

[JeepHammer]

Cannlure is an artifact from manufacture.
In the days between raw lead bullets & jacketed bullets, the cannlure was the way the jacket was mechanically bonded to the core.
For a short period of time, the cannlure was hard wax filled for lubrication.

With current cases/bullets cannlure is often used for a 'Crimp' groove, but it's rarely in the correct location for cartridge over all length to work out.
Cannlure bullets other than pistol hollow points probably wouldn't be made at all if there wasn't a serious demand for them. People just simply demand cannlures.

With pistol bullets, it doesn't much matter, short, fat, low velocity.
With rifle bullets you are compressing a cylinder in the middle.
Crushing the jacket reduces bearing surface,
Compressing hard will shift the core from the middle to forward/backward of the crimp.
Excellent rifle bullets are often ruined by over crimping.

I've read the military has an 80 pound pressure requirement for crimped bullets, 80 PSI to make the bullet move.
It's often possible to get most of that 80 pounds simply by reducing the diameter of the neck sizing ball/rod.
90-95% of rifle bullets won't need a crimp to complicate the loading.
With pistol bullets, its a REAL good idea to MEASURE the case mouth to see what crimp you actually need.
It's a REAL good idea to 'Sneak Up' on the crimp, shoot a few, increase crimp if necessary.

Since crimp permanently damages the brass (no recovery) the less crimp you can get away with the longer your brass will live, and the more consistent your rounds will be.

I STRONGLY suggest a collet type crimper (like 'Lee Factory Crimp') unless your cases are PRECISELY trimmed.
Roll crimpers MUST have a precise length case to be consistent.
Longer cases will crimp harder, shorter cases will not crimp as much.
A collet crimp indexes off the shoulder of the case with bottle neck cases,
It indexes off the case holder with pistol rounds.
This gives you a consistent 'Zero' point that's in the same place every time.

[HiBC]

Its difficult to get a good crimpif you don't have a groove or cannelure to crimp into.
Solids are not compressible.

To confuse the issue,jacketed handgun bullets may well have a knurled cannelure.Lets set that aside for a bit.

Military type jacketed rifle bullets often have a cannelure exactly where the military would want the bullets crimped.It will be a taper formof crimp,rather than a roll crimp (ideally) In a repeater rifle,like an AR,the concern is bullet setback,into the case. Not so in a revolver.

Especially in a beast like the .454,you need a ROLL crimp to resist the bullet coming OUT of the case,for at least two good reasons. The cylinder throat is a slip fit to the bullet,or you could not load the wheel easily. Then you have the cylinder gap,which leaks.Then the forcing cone. Untill you hit rifling,there is not enough resistance for good ignition,especially with slow Magnum type powders.
A good crimp will hold the bullet till you get fire in the hole.

The other very good reason is recoil pulling your bullets. Yes,neck tension helps,but your 454 Casull needs a good crimp into the molded crimp groove.

Crimping as a separate step takes another stroke,butit is WAY easier to control.

If you have a crimped factory load in 454 or 44 mag,look at it close for a model.

A tip: Max 454 loads hit 60,000 psi. You need to have a cartridge or brass in every chamber of the cylinder or gas blasting back through an empty chamber can get hard on theloading gate of a Freedom Arms single action.

You may notice a crimp ring around a cartridge at the base of a bullet.That resists setback in,for example,a lever action,both feeding and stacked in a tube mag ,while the roll crimp resists bullet pull and aids ignition