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Fire forming - lastest data

So I get the purpose and goals of fire forming brass. Read everything I could here and on the 'net on the subject.

I got some 6ARC brass to fireform and I know I could go the bulletless method. But I'm concerned about not getting enuf expansion.

OTOH...I can get some 85 gr 6mm Speer bullets $14.29 / 100. Under $30 for the 180 cases I gotta fireform. (I'll be regularly shooting 90 Bergers from the gun,

What's the latest thnking in bbl life vs. fully expanding brass via fire forming? How low a powder charge can I get full case expansion? Lower end of the published relaoding data? Slower bullets would help the bbl past longer, right?

Any other "pro tips" would be appreaciated.

Thx.
 
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Went through the same quandary when I did a Dasher. Luckily, I shoot it in matches. I found a powder amount that was under full power by a couple grains, loaded my match bullets and shot a match with them. And they shot great! If you are only doing 150-200, that's just alittle more than break in..... rsbhunter
 
Like wedge said, I didn't "jam" mine, but the bolt was a firm close on the false shoulder, and I was .005 past touch. I did an ar arc, pretty much annealing, form to where the bolt locked up, load and shoot.. one thing, the guys (and ladies) on this site are the BEST!!! I honestly mean it. When I got ready to fire form my Dasher, they all held my hand and walked me through it. Now I'm waiting on a 22 BRA barrel, but already have the brass 80% done because , once again, the people here will give you the RIGHT info..not alot of keyboard commandos here.rsbhunter
 
If you are shooting 6ARC brass in a 6ARC chamber why would you need to fireform? If I am missing something let me know, but to me fireforing is necessary for making a cartridge fit a chamber that isn't exactly the same as the case was made for. Yes when putting virgin brass in a rifles chamber that are the same it will fire form perfect and I guess that is fire forming but to such a small degree that there is no way i waste barrel time with only chamber fit in mind,
 
Ebb, you are correct. Case forming to a different shoulder angle, longer body, straighter case taper is not being done. However, I don't think it hurts to use a mid level load otherwise first firing to help set the case to the chamber. Some believe it can also help "harden" the case head to help with primer pockets ?. But I did miss the 6 arc brass part in the post. rsbhunter
 
My thinking is that unless your going from a standard cartridge to an Ackley improved cartridge, the powder volume isn't changed that much.

The improvement is in that the casing conforms to your chamber.

For my 257 Roberts, I'm forming 7X57 Mauser cases. I load to my accuracy charge to fully "fire form" to the chamber.
I also do this for my 257 Roberts AI.
After that, I load to my AI powder charge.
 
When i did my 6PPC cases I was shooting a pretty stout load of H322 and it took several firings to get the cases to have square sharp creases in the shoulder area going mild on the first shoots on new cases seems like the wrong way to go. I like to get them to fit ASAP and finalize my load.
 
There are a million different thoughts on this,some believe that hot loads are the way to go...some thi k that the first firing being a medium load preserves primer pockets...would be great to see a test done on it....rsbhunter
 
Ebb, you are correct. Case forming to a different shoulder angle, longer body, straighter case taper is not being done. However, I don't think it hurts to use a mid level load otherwise first firing to help set the case to the chamber. Some believe it can also help "harden" the case head to help with primer pockets ?. But I did miss the 6 arc brass part in the post. rsbhunter
I wouldn't think the case head would work harden. You need the metal to stretch to work harden. You should have practically no movement of metal in the head unless you are shooting really hot loads. Fifty years of reloading never had a lose primer pocket. My 6BRX shoots under .500" fireforming.
 
From what I've read, the head hitting the bolt face hardens the brass??? Like all the other rabbit holes we go down, it takes extensive testing to quantify, or disprove. Been reloading long enough to be in disbelief over $600.00 priming tools,or $8,000 (?) Powder scales/dispensers that you LEASE, and can't sell without the companies owner's permission....rsbhunter
 
Load up some rounds and see how accurate it is. Might be accurate enough for your purposes. When I was fire forming to make 22-250 AI brass I was getting 5/16" groups with a fire forming load. Good enough for varmint hunting. And this was out of a 16.25" Bullberry barrel (T/C Encore).
 
From what I've read, the head hitting the bolt face hardens the brass??? Like all the other rabbit holes we go down, it takes extensive testing to quantify, or disprove. Been reloading long enough to be in disbelief over $600.00 priming tools,or $8,000 (?) Powder scales/dispensers that you LEASE, and can't sell without the companies owner's permission....rsbhunter
I require proof for everything not just opinion. To work harden I think the brass has to stretch beyond the elastic limit .
 
Well, isn't the process of annealing the necks of fired brass to return the "work" hardened brass to a more malleable state? What causes the brass in the neck/shoulder area to harden? rsbhunter
 
I measure the go gauge and size the brass to the same measurement since the headspace should not exceed 0.003". No-Go Gauge is 0.004" longer for most cartridges disregarding military chamberings.
223rem and 5.56 x 45 have a huge difference in acceptable headspace. Same applies to 308win and 7.62 x 51.

The Hornady overall modified cases measure EXACTLY the same as a GO-Gauge of the same cartridge. Way cheaper than an actual Go-Gauge.

So sizing back to go-gauge specs will ensure you're not sizing more than 0.003"

I like to keep things simple. I'm not a BR shooter. Just a target and LR wannabe.

Fireforming to the chamber doesn't matter because when you re-size the brass you're sizing the sidewalls of the brass as well. You can always get a custom die made based on your chamber reamer, or a cast of your chamber.
 
If you are shooting 6ARC brass in a 6ARC chamber why would you need to fireform? If I am missing something let me know, but to me fireforing is necessary for making a cartridge fit a chamber that isn't exactly the same as the case was made for. Yes when putting virgin brass in a rifles chamber that are the same it will fire form perfect and I guess that is fire forming but to such a small degree that there is no way i waste barrel time with only chamber fit in mind,
The factory (Starline) brass is 0.015 under chamber length. (This one is a 12.5" bbl semi auto)

In my other semi 20" bbl 6ARC, I got 0.5MOA after I "stretched" the brass.
 

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