.475 Linebaugh-RCBS seat/crimp in one step-?

[TScottO]

This is the first time I have tried to seat/crimp in the same step. In the past I have always made seating/crimping two separate operations. I have followed the instructions to the "T" and I also tried adjusting this die my own way, both yeilding the same result---crushed and wrinkled cases.

This is the process:

1. I mount the die high on the press, but deep enough to allow me to  seat the bullet with the seating plug.
2. I place a bullet in the hull and extend into the seat/crimp die.
3. I adjust the seating stem to where it touches the bullet.
4. Then retract the ram and screw the seating plug down to where feel the cannelure will close to the case rim.
5. Then rising the shell/bullet back into the die and checking bullet seating depth. I repeat this till the bullet is seated deep enough to give a good long crimp surface.  ~ oal of  1.735
6. Then fully unscrew the seating stem and screw the die down, a sereis of times, till there is a nice firm crimp in the cannelure. Then tighten the lock nut.
7. Screw the seating plug down till it touches the bullet and tighten the lock nut.

The cartridgege I used to set the die up with is beautiful, but every piece of ammo I try to put assemble after this process becomes crushed and wrinkled.

I'm using 400gr XTp Mag bullets.
I have tried this on an RCBS RockChucker Supreme and a Dillon 550B press.

Do any of you see error in this process? Is it best to seat/crimp in two separate steps?
 
 :?

Thanks
Scott

[KN]

Your proccess seems alright. Your probably just trying to put too much crimp on it. That is what usually causes crushed or wrickled cases. Back your crimp off a little and be sure its crimping into the groove and you should be all right. I do have one question though, what do you mean in step 5, ( "good long crimp surface" ) ?     KN

[TScottO]

I am refering to how much of the case I allow to extend past the beginning of the cannelure. The cannelure is ~ .060". The more surface area that is crimped the better the case will hold the bullet under heavy recoil. This may shorten the oal just a little bit, but I've never had bad results with this method.

I tried backing off the crimp some. When I lessen the crimp to where the cases don't buckle...you cannot see any roll at all on the case mouth and you can see a gap between the case mouth and the cannelure.

I'm sure people have had success with this type of set up... I'm having no luck at all.

 :cry:

Thanks
Scott

[Lloyd Smale]

didnt your hornady dies come with a factory crimp die mine works great.

[KN]

This is a new one on me, I crimp and seat in one all the time. What happens if you do it in two steps? Seat first, back off the seater stem and then crimp.   One other thing you have to remember is that the bullet is still being pused into the case as you are crimping. If you start the crimp too late it may be hitting the end of the groove too soon. Try backing the seater so its not so far over the groove.   KN

[Mike C]

Both the Hornady and Speer .475 bullets have a shallow cannelure that doesn't allow much of a crimp, there's no place for the brass to go.  Compare them to a proper keith bullet that has a crimp groove that has a radius built right into it that the case mouth forms right into.  I have had the very same problem as you describe, you definately have better results by doing it in two steps.  When you attempt to seat and crimp in a single step the crimp section of the die is attempting to begin the crimp before the case mouth is past the trailing edge of the cannelure and at the same time additional force is going into the case as the bullet is still being shoved into the ever tightening case mouth. :wink:

Mike C

[MS Hitman]

Just split up the processes.  Another poster was correct about the shallow cannelures, but I get very heavy crimps on my loads, so it can be done.