Fireforming virgin IMI brass for match shooting use

[CHeatermk3]

I have a stash of several hundred virgin IMI 30-06 cases which are seperated into lots of 80-100; all weighing within 1.0 grains. I fireformed the first, lightest lot and have started using them to find "the load" for my Sporterized m-1917, only to find that they are not fully fireformed, as evidenced by slightly backed-out primers after firing.

Should I just keep shooting them while working up match-type CB loads, or load up j-bullets full-power? I really do not look foreward to another lengthy de-coppering as I had to do when I first got the rifle.

Also, any fireforming load suggestions appreciated.

[LAGS]

Primers backing out, then it is too light of a load.
But that does not mean that they are not fully formed to your chamber.
They are now once fired, and way more accurate if resized properly than the original virgin case loading.

[CHeatermk3]

They were loaded using the NOE 311-169 ELCO over 21.0gn H-2400 and show no soot whatsoever on the case necks; it seems they are sealing up fine. I had thought they were fireformed - they are now twice-fired.

Guess I'll hafta "bite the bullet" and just shoot full-power j-words then run another can of wipe-out thru the bore--losing a week in the process.

Guess I ought to go ahead and do another lot of 90 for good measure.

Still wanting suggestions for a fireform load--I had set my boolits out into the lands to keep the case heads against the bolt face but it seems this did not work with my alloy and boolit/load combination--IIRC it was the Lee 309-180-R over 18gn H2400. Alloy was/is WD COWW.

[Bjornb]

Most important detail when fireforming: your bullet must touch the rifling when chambered. I normally seat a cast bullet long, letting the rifle bolt seat the bullet when closing. Now your case head is tight against the bolt face, preventing the primer from backing out. When fired, the shoulder can now only move forward, thus forming itself to your chamber correctly.

As for a powder charge, I have used many different powders with good success. In the 30-06 a 15 grain charge of Unique under a 200 grain bullet (311299) will give you about 30K psi pressure; this should be sufficient to form the -06 case. MV will be around 1700 fps, slow enough to give decent accuracy in the 1:10 twist 1917 barrel. Good luck.

[Scharfschuetze]

A couple of causes.

First: What is the actual dimension of your chamber? If you don't have HS gauges, then you can fire a full power load in the rifle and use a one of the various HS measuring tools to determine you bolt face to datum line. Stony Point, which is now marketed by Hornady is probably the most inexpensive. With such a set up, you can then adjust your die to your chamber's HS and not overwork your brass.

Two: As mentioned above, perhaps your fire forming load was too light. Try a more powerful load.

Three: Unless you have a sub MOA 1917 rifle, fire forming your cases to it may be an extra step not worth taking. Still, when one has full confidence in his ammo, he usually shoots better. I shoot several 30/06 military rifles, so I just full length resize for compatibility between all of 'em. I've not noticed any loss in accuracy between 1917 US Enfields, 1903 Springfields and M1 Garands by doing so.

[Bjornb]

We must have been typing at the same time. I see you already seated the bullets correctly.

Check out this headspace gauge (like Scharf is talking about): www.larrywillis.com
I've been using it for about a year now. Works great.

[Pipefitter]

Way back when I first started reloading bottleneck rifle cases I had a similar problem, light loads were backing the primers out a little bit. An old-timer explained to me how to "properly" set up my sizing die to fit my rifle's chamber. Fire a "full power" load, either factory or handload, then lube the case as you normally would. Use a candle flame to smoke the neck and shoulder of this lubed case. Now back the sizing die off of the shellholder a couple of turns and run the case into the sizing die. remove the case and inspect the neck area, you will see where the neck has been sized and how far to turn the die down to just contact the shoulder. Turn the die down about one eighth of a turn at a time until the blackening on the case indicates that you have just touched the shoulder, then tighten up the lock ring. This may or not be with the die touching the shellholder, a "long" chamber (but still within specs) and a "short" sizing die can lead to premature head separation by over working the brass even if you follow manufactures instructions to size the case by touching the shellholder to the sizing die at the top of the presses stroke.

As for the brass that my have been "short sized" already, I would use a mid-range load of the powder you are using to fire form and seat the bullet (or boolit) out far enough to contact the rifling. This should hold the base of the case against the bolt face to allow fireforming to happen in your chamber.

[CHeatermk3]

Thanks all for the replies--The boolit I'm using appears to be designed for this rifle--seated to the front groove, the GC is flush with the neck-shoulder junction and the straight portion of the nose, just ahead of the end of the case mouth is lightly marked by the lands. When I set them up to fireform I put the boolits firmly into the lands; then assumed they'd been formed to my chamber; not so.

Maybe the alloy used was soft enough that the firing pin strike shoved the round a bit farther foreward, or the charge didn't generate enough pressure, or the IMI brass is exceptionally tough, or some combination I've yet to imagine. Whatever, after two firings they're still not fully fireformed.

I'm ordering some cheapo 147gn FMJ bullets today and when they get here a full-power load, with bullets touching the lands will be used to get the job done.

Hopefully.

After that I'll be using bushing dies to neck-size and experiment load development....I'd really like to win a match before I leave this world and I'll need all the tricks to do it considering the company I shoot with--several record-holders shoot here.

[Scharfschuetze]

After that I'll be using bushing dies to neck-size and experiment load development....I'd really like to win a match before I leave this world and I'll need all the tricks to do it considering the company I shoot with--several record-holders shoot here.

I often use bushing dies for several calibres, particularly for long range match loads. With cast bullets they work great, but you'll want to get the misnamed Lee Universal Expander die. It doesn't expand a thing, but it puts a nice flare on the lip of the case in order to seat cast bullets without damage to the bullet. NOE makes true expanding plugs for the die.

I wish you luck on your quest to win a match. I'm looking forward to our clubs cast bullet shoots this coming spring as well as the National Match rifle courses.

[samari46]

IMI brass is good stuff. Shot a bunch of the 308, 308 match, 30-06 and 7.62x39. Sure wish Weideners would bring it back. Frank