This will probably be of interest to those who do fireforming. I was out getting the kid sighted in for the deer opener here in Alaska - the 5 month season begins August 1st. I had a box of virgin cases that I wanted to fireformed for my .30 Gibbs. I was trying a new approach and it didn't work as planned.



I was using virgin RP 35 whelen cases. The load was 14.5 gr Unique + Speer 130 gr FP + Fed 210 primer. I had not used this load to fireform with before. I usually use a 150 - 180 gr pill and a mod load of "faster" powder - 4064, 4895, etc. I have also used the Cream-o-wheat as inert filler w/o a bullet sucessfully, but not in this particular wildcat.



Needless to say (please examine image) this load did not produce enough pressure to fireform the cases properly. Not quite a disaster, but I pretty much have to go thru the entire process again!!!



The Image show the following:



Left - loaded cases. The 35 Whelen case has been run thru a .30 cal neck sizer for a tight "crush" fit in the chamber. Funny looking double shoulder, eh?



Middle Left - Funny looking bulb shaped neck.



Middle Right - A little less bulb shaped.



Right - Almost fireformed, but a radiused shoulder and the shoulder moved back about 1/16".







All loads fired just fine. All loads were exactly the same, but produced a wide range of fireformed shapes as shown. Rather curious, I thought. The biggest problem is that the load produced enough pressure for the case head to grip the chamber walls, but not enough to fully blow out the neck and shoulder. The shoulder has pulled back the noted 1/16" +/- on all, thus there is a headspace problem on all of them. I'll have to run them back thru a .338 expander to get a good shoulder to headspace on. This might have worked with 20.0 gr Unique. Don't think I'll try this specific receipe/method again.

Musk, I just did a bunch of fireforming for my .260AI. I use a med. burn powder, starting load w/ the bullet jammed into lands. I also have to fireform for a .338x74Keith. The throat in my #1 is too long for the bullet to reach so when I neck down I leave a slight shoulder that requires me to force the round into the chamber, basically the false shoulder centers the round in the chamber. I also us a med. burning powder w/ a starting load.
I have fireformed .375URM brass into .404jeffery by using 27grIMR4227, COW filler & a wax plug, works great.

MM, Unless I'm missing something I can't see why you could not use the Whelen cases loaded to a near max 30-06 loading with medium or slow burning powder and a 150 gr. bullet.I've used factory loads in Improved chambers while hunting when I had to.In my 358X404 imp.I use a stout charge of 4350 behind a 250gr. bullet. I guess I'm lucky.I've not had any bad experieces fire forming.

If you feel adventurous some day, try using an 06(full load) with the bullet seated out far enough to be jammed into the lands. I used this method with a 6mmX.270.No I didn't fire a .270 in the rifle. roger

I normally fireform with a max load for the parent cartridge with the fastest powder listed, with a bullet jammed into the lands if I don't have a false shoulder. If you already have a crush fit on the shoulder, it's not necessary to jam into the lands. Just remember that a significant portion of the energy created goes into conforming brass to the improved chamber, so don't worry about excessive pressure. BUT, you do have to generate enough pressure to get a good fireform with a crisp shoulder, and one firing should do it if your load is stiff enough.

MuskegMan; I also use the 35 Whelen case to fireform for my 30 Gibbs. But I have always used a load of 57 grains of IMR 4350 behind a 180 grain bullet for the job. I used the 180 because I have a lot of pulled bullets of various makes around. I have had 100% success with this method on the first firing...nice sharp shoulders and no lost cases. I have a C&H Neck sizing die that I use to prepare the Whelen cases to fit with a slight "crush" Regards, Eagleye