Fire forming brass

KDX

KDX

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What is the most commonly used way to fire form brass? I have a .257 Roberts AI barrel on the way and I was just going to use the max load (as per Hodgdon's website) for which ever powder I'm going to use and a 75gr V-Max. Probably 46gr of H335 as I have several pounds of it sitting here and I don't use it very much. Once I get the brass fire formed I will use some H4350 and see how that goes with the V-Max bullets. I'm going to use this for coyotes if I get out this year.:D
 
Just load your standard ammo and it will form to the new barrel, I have a 25-06 mashburn and it will form standard 25-06 brass with no problems, but I usally make my brass from 06 or 270 brass and fire form with Red Dot and cream of wheat, works either way.
 
When I fire-formed brass for my 223AI, I considered the cream of wheat and pistol powder method but I eventually loaded up some 75gr Amax and Varget (my intended load components) with a close to max load and headed off to the local gopher patch. I was pleasantly surprised in how accurate the load was and how damn fun fire forming brass was.
 
I think I'm going to set up a target at 100 yards or so and put 50 through it and see how it groups in 5 shot strings. First aftermarket center fire barrel for me.
 
If I were nervous about the possibility the AI did not headspace the same as the parent brass...I would use a minimum load for the parent cartridge and seat it into the lands about .005.... that way, if there was excessive headspace, the "jamb" will keep the base against the bolt.
 
It's a Savage and I'm going to use a piece of properly sized brass to set the head space. I'm going to have to read up on it first as I think there is a way that you do it with the firing pin removed from the bolt and use tinfoil (or something similar?) as a spacer for a wee bit of wiggle room. I can't remember off hand and will have to research it or contact Mystic for the low down.
 
KDX; A proper AI chamber should be cut so when you close the bolt on a standard case [new], there is just a bit of "feel" as you close the bolt.
Dennis Sorensen has done a couple for me, and they are perfect.
I much prefer the COW method of fire-forming, but to each his own.
Regards, Eagleye.
 
KDX said:
It's a Savage and I'm going to use a piece of properly sized brass to set the head space. I'm going to have to read up on it first as I think there is a way that you do it with the firing pin removed from the bolt and use tinfoil (or something similar?) as a spacer for a wee bit of wiggle room. I can't remember off hand and will have to research it or contact Mystic for the low down.
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Please do yourself a favor and buy a headspace gauge. Call Mysticprecision and he can hook you up. They are cheap and are the only way to insure proper head space.
 
KDX said:
It's a Savage and I'm going to use a piece of properly sized brass to set the head space. I'm going to have to read up on it first as I think there is a way that you do it with the firing pin removed from the bolt and use tinfoil (or something similar?) as a spacer for a wee bit of wiggle room. I can't remember off hand and will have to research it or contact Mystic for the low down.
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I use formed parent case (not LOADED - no bullet in the chamber while setting headspace), barrel in blocks in a stout 6" vise, spin action on with bolt cocked&locked with case in chamber (no forward pressure from firing pin)crank it as tight as I can with one hand turning on the action, then snap up the barrel nut. Tightening the barrel nut puts about .003" of headspace into the equation. If I tighten with both hands (I'm a huge gorilla) - I can set it too tight. I can crush the parent case with the mechanical advantage of threads that it becomes impossible to chamber the parent case. So - after I set the headspace with one sized parent case, I grab another, as has already been said - the bolt should be a bit stiff to lock down, but not a "lean hard" or "grab a mallet" affair.

I own several AI savage chambers and I swap barrels around all the time.

I also load at max to fireform. Gets the shoulders straight in one single pop. After that I neck size with lee collet die, seat bullets with Ai chamber reamed Forster BR seating die.

Congrats on the new aftermarket tube! You're going to LOVE that rifle!
 
What are the dimension changes of the case between the parent cartridge and the AI version? If they are very similar, as in same distance to the bottom of the neck but with a different shoulder angle I would think you could use a normal 257 case. Might need a very soft touch though. Just one guys opinion. Is there an actual headspace gauge available for the AI?
 
I have a ackley improved 6.5x55, and have fireforemed lots of cases just by shooting a loaded standard case, it is accurate enough to hunt with and very reliable to shoot even with the standard cases.
 
KDX said:
That's excellent advice, but how do I get the initial formed case?
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As it's a 257 Roberts AI, just buy a box of regular 257 Bob ammo, and thread the barrel in as previously posted. The AI cases are a little bit shorter then the regular cases to ensure no headspace issues while fireforming the AI cases from their parent cases (0.004" if memory serves). A headspace gauge will make this go a lot easier though. FWIW - dan
 
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