Fireforming blanks?

[Jim]

Earlier this morning, I sat down at the bench to make some rifle blanks to entertain the troops on New Year's Eve.
I loaded 42.5 grains of WC820 in a .308 case and plugged it with half of a foam ear plug. I took it up to the range with my 1916 .308 Spanish Mauser and lit it off. Nice, big, rolling boom. I thought "Perfect. The kids will love it".
I got back to the house and pulled the empty. I immediately noticed the case was perfectly fireformed to the chamber. Hmmm...
If I can fireform bottleneck cases without boolits, I still have the noise, but no boolits to worry about.

Below are two identical cases. They are LC 69 M1919 cases reformed to .308. The one on the left is full length sized, not yet fired. The one on the right is the fired blank. You can clearly see the difference in the two.

http://fgsp.files.wordpress.com/2010/12/pics-005-e1293132713391.jpg

As you can see below, there are no pressure signs on the primer.

http://fgsp.files.wordpress.com/2010/12/pics-e1293134641683.jpg

[scrapcan]

You could also do it with less powder/different type of powder. Search for fire forming wildcat cartridge or just fire forming here on the site.

[Wayne Smith]

Yup, been doing it that way for a long time. The Holy Black works, too.

[MtGun44]

I expect that ~ 10 gr of pistol powder would work similarly with much lower cost.

10 gr unique is safe under a big cast boolit, so will be safe without one, but I have not
actually done this.

Bill

[BOOM BOOM]

HI,
IIRC you could use 10gr. unique & dried cornmeal.:Fire::Fire:

[Jim]

Actually, my initial intent was to make some celebration blanks for New Year's Eve. The fact that the load could be used to fireform was coincidental.

[leftiye]

30/30 in a 14" contender full of powder (can't remember just which) and a bit of wax over powder makes good fourth of July noises! Cops wanna know if it's M80s.

[lwknight]

Black powder is more impressive and especially so if you pack wheat flour on top of it.
You get a awesome BAHH BOOM!!

[BruceB]

I've been fire-forming .375 Ultramags to .404 Jeffery with perfect success. The new cases are run through the .404 sizer die just far enough to allow them to BARELY chamber in the rifle. THey are then primed, charged with 21.0 grains of 2400, and filled almost to the mouth with cornmeal. A wee bit of tissue serves to hold the whole mess together, standing upright in a loading block. Firing them vertically (at the range!) gives a healthy concussion and perfect .404 cases.

Years ago, I was given a bunch of .264 Winchester brass, and modified them to fit a 7mm rem Mag chamber. They were primed and charged with 20.0 Bullseye...NO filler or tissue of any kind was used over the powder...JUST Bullseye and NOTHING ELSE! Firing these vertically expanded the necks to 7mm very nicely, although with a huge flash and bang. Pressures were moderate, based on extraction effort and primer appearance.

[ebg3]

I have a 264 STW and wanted to do a final fire-forming on necked down 7 STW brass. I used primed brass with 30 grs of N 340 powder and no bullet or filler. I just fired the gun vertically and the brass came out great. The only problem I had was with hard powder fouling in the barrel. I scrubbed that barrel with everything I could think of and after many hours I got it clean. I'll never try that again, at least with that same recipe/setup.
EG

[deltaenterprizes]

Bench rest shooters I know use fast pistol powder and plug the case with bar soap as it is easy to clean out with plain water.

[firefly1957]

lwknight NEVER USE WHEAT FLOUR OR CORN STARCH both will cake and can obstruct the bore.
I read this when people were trying to buffer shot loads but actually had it happen when using black powder for a noise maker. I had a heavy 3/4" pipe with 100 grs powder and put flour on it for a fireball, I had previously done this with wadding and it worked fine, but the flour split the pipe and was cemented to the inside of it. It was a good thing I tested it in a safe way or some one could have been hurt.
Cream of wheat does work well for filler I also used to use the paper from the old computer tapes (tiny dots from holes in paper tape that was the program) but it is used up now.
Note that that was not water pipe but steel with a 3/16 inch wall so it was strong and no seam either.