Fire Forming Brass

[appleseed]

What are the rules of thumb for loading new brass to fire form? (.20 vartarg from new .221 fb brass) Lower range of powder, heavy or light bullet weight, set to lands or otherwise?

[Der Verge]

Straight from 6mmbr.com
"No special dies are need to form 20 VarTarg brass. Simply run a .221 Fireball case through a 20 VarTarg full-length sizer die--then load, and shoot."

[appleseed]

Read that one before starting the project...still what is safe, light loads, heavy bullets, or the opposite,  bullet seating depths?

The case shoulder angle changes during fire forming doesn't it?

Have all ready sized new .221fb brass.

What is prudent? Question generic related to caliber.

[Eric in NC]

Don't know your cartridge but generally with fireforming (esp. when shoulder position or angle is changed) you want a "medium" load (not mild and not max) of a poweder that is on the fast side for the cartridge in question and a bullet that can be seated into the lands - the idea is that the bullet holds the case head back against the bolt and any gaps at the shoulder area will be filled when the cartridge fires.

This is the process I use when fireforming 7mm TCU, 375-06AI, 22-250AI, etc.


Now for straight neck up/neck down in caliber (i.e. 30-06 to 338-06, 6mmBR to 7mmBR, etc.) just start doing load development - no special procedure required.

[Apache]

See here for FF methods:

http://www.6mmbr.com/6improvedform.html


Personally I use method #2.

[appleseed]

Thanks folks, the 20vt neck angle does change from the .221fb, it's not much though.