Fire-forming or wasting components?

[HappyGVM]

Hi Everyone,
I just prep'd a batch of new brass (50 ea) that I will use for load development on an old Rem 700 in 308 Win, bull barrel. Really, I'm going to try to mimic the performance I got out of shooting the old Federal Vital Shock factory loads with 165 gr SGKs. Twenty years ago, that ammo produced .75 in groups out of the rifle at 100 yards but that's another story. I just wanted to know whether going through the process of firing the new brass to "fire-form" to the chamber is worth the expenditure of components? Or should I be searching for the sweet spot (in terms of powder charge) with these initial loads. I have plenty of N140 and Varget on hand but don't know that going through 50 shots worth of components is worth any incremental improvement in accuracy the FF brass will provide for a non-competition rifle.
Cheers,
Jerry

 

[waveslayer]

Well it depends... do you have dies set up to maintain what you fire form? If not, no. I develop several loads for my rifles, one for new Brass, one for once fired brass.

It's a bigger deal if you are AI a cartridge etc. On a standard bolt gun, don't waste the time. It's all a matter of the bullet be concentric to the barrel

 

[cohunt]

I'm not sure if it's much different if you are full length sizing, if just neck sizing it might be worth it, but I've seen 3-4firings on some rifles before shoulder is fully pushed forward too.

You could always do a few and compare

 

[Greatgrandad]

Depending on what you are intending with your load development, it could be a waste of time and components, but if you are simply desiring to "fireform" the new brass to your chamber and then begin developing your load's accuracy, you can save valuable components and even some throat wear by using cheaper components.

For decades, I, and others, have fire-formed various AI, wildcat and other by using cheap demilled (pulled) bullets, cheaper FMJ's in 30 and 22 cals, cast and other, and using smaller, appropriate amounts of pistol powders like Red Dot, Unique, Blue Dot, etc. These loads can be derived from using manuals like Lyman's Cast Bullet Handbook.

Typically and due to lead's lower friction ratio over jacketed bullets, I look for a load a few grains or so heavier than the jacketed bullet I intend to use and its pistol powder charge that produces around 35-40K "CUP" to properly form the case, or if its a lesser psi case like a 30-30 based wildcat, then a little less. I.e. if I am going to fire-form a 308 using a cheap 147 FMJ or some demilled, cheap 150 SP's, I'll look for a load in the 160 or so "lead" bullet. This will give similar pressure with the lesser weight but higher friction jacket.

These fire-form loads produce appropriate pressures to form the case, but are cooler, use far less powder amounts, produce less wear on the throats, less recoil, and are much cheaper than burning expensive powders and bullets.