Forster 223 micrometer seater variances?

[cs5700]

I had the same problem with a Forster seating die and Lapua brass for a 6.5CM. The problem went away when I started annealing and using a mandrel to set neck tension. My conclusion was that I had too much neck tension using the Forster sizing die with the expander ball and was getting inconsistent spring-back with brass that wasn't annealed. I don't remember what I had for neck tension, but the bullets seat a lot easier now than when I was having the problem.

 

[Firearmsunlimited]

With dies that do not have a VLD stem the bullet can get slightly stuck in the stem and be pulled out of the case .010. Call Forster, I'm sure stems are relatively inexpensive. Don't let them BS you and say their stems are a one size fits all. They have a precision machine shop so they should be able to cut the correct taper and angle for ELDM's and Berger VLD's.

 

[dellet]

Rockchucker press, 75g ELDMs, just your normal basic brass prep, 1x fired lapua brass, no annealing, and not a compressed load. 24.7g N540 at 2.485"

I am wondering how you checked for compression. You can be displacing powder, without actually “compressing”.
Using a sized case with the neck expanded for a slip fit of your bullet, drop your powder charge, gently push the bullet into the neck until It stops. Measure that length, and that is where you will start adding resistance to the seating die.

Sometimes 100% density, or even 90%, can’t be reached without extra force required to displace the powder around the base of the bullet and between the case. If your powder drop is not consistent, your seated depth into the powder, probably won’t be.

Calculations based on volume assume no airspace in the powder column.

The other thing to check is to make sure the die body is not contacting the shell holder. That can deform the opening and the insert will bind.

 

[Wild Bill IV]

Looks like they answered those questions back at posts 4, 5, 6,

One more variable to add to this list!!! The standard steam is NOT designed for the long pointy tangent ogive bullets!!! It is noted in the instruction with the die that a different steam has to be purchased for the low drag bullets!!! His problem is the outer contact surface of the stem is not contacting the bullet in the designed area, but being pushed down by the the very tip of the bullet in the shallower cavity of the stem!!! Forster seating stem were susceptible to cracking so they added strength with a shortened relief cavity!!! Without pointing the bullet, his seating depth is based on the irregular tip meplat which affect the variability in Bullet Ogive to Cartridge Base length which is his preference to measure!! It could also be he is deforming the bullet tip too!!!! The BAD news, his Cartridge Overall Length would be more uniform the way he is set up right now!!!

 

[Wild Bill IV]

I had the same problem with a Forster seating die and Lapua brass for a 6.5CM. The problem went away when I started annealing and using a mandrel to set neck tension. My conclusion was that I had too much neck tension using the Forster sizing die with the expander ball and was getting inconsistent spring-back with brass that wasn't annealed. I don't remember what I had for neck tension, but the bullets seat a lot easier now than when I was having the problem.

As an engineer, your saying that 100-200 psi of pressure to seat a bullet was too much when it requires over 1000s psi to form small base!!! Presses are designed for maximum pressure, especially in the bottom out, cam roll over position with little movement downward with the extreme force!!! Seating a bullet takes around way less than a 1/10 of the total press design!!!