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.

 

[HappyGVM]

Thanks for the feedback. Those "low power" loads are intriguing. I have a bunch of International Clays powder that should work.

 

[Korhil78]

I just do a load with new brass and then tweak it a little after I have the once fired brass. My loads now a days are not at max pressure which you don't want to load max pressure loads in new brass.

 

[Koda_]

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 actually tested for this last year when I got a new AI chamber, short version is its just wasting components.

My test is no where conclusive, but I compared velocities between virgin non AI brass and then that same brass after it was fireformed with the same exact charge weight. There was a measurable drop in velocity but it was less than 1%.
Not anything to worry about, and thats fireforming brass to Ackley dimensions.

 

[Ark. Trapper]

^^^^^This right here. I shoot 3 Ackley improved cartridges and velocity, group size, and point of impact aren't affected enough to notice usually. Fireforming brass to a standard chamber is a waste of time and resources unless you're a benchrest competitor

 

[FEENIX]

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

Jerry,

For what it is worth, I usually experiment with different loads and powders with virgin brass. I have done COW, and hydraulic forming dies on my wildcats, but I do not develop the load until the brass is fire-formed off the chamber with a full load. Good luck!

Ed

 

[243winxb]

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?

My test with Remington 40xb in 243 Win showed an accuracy improvement by a Full Benchrest Prep of new Win brass.

New brass from bag= 3/4" @ 100 yards.
Fire formed Benchrest prep= 1/2"

The standard load used over many years is IMR 4350- 42 to 43 grs- Br2- Sierra #1530, 85gr hpbt- Win brass- Weight/ sorted- neck turned- bushing dies.

Switching to Berger 90 gr hpbt Bullets & IMR 4831 can produce 5 shot groups under 1" @ 300 yards, at best. Not always.

36 power scope.

After brass is fully Benchrest preped, sort by weight to 3/10 grs. Greatly reduces fliers using Rem or Win brass. I buy 100 brass at a time, prep & sort by weight. (Gives retired guys something to do)

 

[243winxb]

old Rem 700 in 308

A used Rem M600, Mohawk in 308 win., i test fired with my handloads, avereged under 3/4" for 20 rounds. No load workup. Used IMR4895 & 150 gr Sierras. Standard dies & factory brass.


You dont know till you compare. Good luck.