[singleshotbuff]

Hello all,

I have a rifle (7X57mm) that shoots substantially better with partial sized cases (almost 1" smaller groups versus f/l sizing). I have several boxes of brass that I'd like to fireform to the chamber (which is slightly oversized) so that I can partial size them. I'd rather not waste any of my Sierra match bullets (a bit pricey) just to fireform the cases. Since I have no other 7mm bullets on hand, is there a way to fireform these cases without bullets? I'd like to get as tight a fit in the chamber as possible. Any help is appreciated.

SSB

 

[arkypete]

I've never done it but I read......

It may have been George Nonte who wrote about using a case full of corn meal with a fast burning powder.
As I remember the corn meal performed well, didn't need to go to the range, made little noice and only left a bit of corn meal in the yard.
Jim

 

[ribbonstone2]

The corn meal (or grits for us Southern folks) method works fine, but don't believe that what exits the barrel isn't dangerous at very close range....it is.

Hard to make a powder carge recomendation as brass varies. I'd start with 5gr. of Bullsye/Red Dot/700X (or whatever fast pistol powder you have one hand), a small wad of TP (about 1/4 a sheet) pressed on top of the powder, fill it with grits, the other 3/4 shttet of TP pressed down on top to compress the corn meal (about 1/2 way dwon the case neck). Some debate here, but if the idea is to have the case set back completely, I'd WAX the case. That last would cause some problems with high-pressure bulleted rounds, but here it helps keep the case from clinging to the chamber walls.
Do point the rifle DOWN when firing to help the crumbs/burened bits fall out of the rifle rather than into the action, do clean the chamber ever few rounds (again...want the waxed case not to stick but to set back), and BE CAREFUL of the blast.
--------
Get one of the plastic buckets used on construction sites (empty). These usually have a snap lid with a punch out hole/spout. Fill the bottom of the bucket with 4" of dry sand. On top of the sand, fill the buck to about 1" from the lid with ripped up carpet backing, cut up bits of old carpet, or ripped up bits of foam padding (or any combination fo the three). TAPE the LID back on (tape it on good).

Place barrel of the rifle into the hole/spout and fire. Actis like a big muffler...get a low "thud" that won't bother the nextdoor neighbors.

WARNING: keep some water at hand...you can set the insulation on fire.

 

[ribbonstone2]

..sorry...posted too quick.

Naturally, iof the case isn't blown out with 5gr. then move up...move down if thigs seem to violent.

Use this process to make 38/55's from 30-30's and .401WSL from 7.62X39's (along with less drastic forming). Now I do tend to cheat...if a forming load prepared as above doens't quiet fill the case out, I'll INCREASE the compression of the corn meal...if that won't work, will try both increased compression and a bullet lube plug in the case mouth.

The bucket/muffler has been used for years....just change out the ripped up padding/backing every so often. The second reason for getting the lid on tight is that when you plug the spout hole after use, it cuts off the air supply as a fire safety.

Just be sure to only hold the muzzle shallowly into the ripped up foam and not into the layer of sand.

 

[Paul Nichols]

Fireforming

All the stuff with corn meal or Farina or whatever works well like all of the recommendations, it just isn't as much fun howeve as fire forming with a bullet going down the bbl. Suggest you find someone to run you a batch of cast bullets to form with. Better yet, think about getting into casting, get a mold and get started that way even if it is a Lee w/cake cutter. Shot a lot of them cast lubed and sized that way when I was much younger. Regardless of how you do it, it is all a learning process that keeps you shooting and that is what counts.
Good Luck,
Paul

 

[leadbutt]

10 grains of unique and just enough kleenex to hold the powder agaisnt the primer, point barrel into the air in a safe direction and pul trigger out comes fire formed brass.
Have been doing this for years on 32-40 and 30-30 to get 38-55 bras for reloading

 

[jack1k]

I talked to the people at Sierra, and they
told me not to use cornmeal, but to use
cream of wheat or farina.

later
jack1k

 

[BrianK]

The rule of thumb for the starting load is weigh a case full of suitable powder (fast powder), and the starting load is 1/10th of that weight. The one time I did this I had to increase the charge substantially to get a proper fireform (radical shoulder), but start by using the 1/10th rule of thumb and work up. IMHO, this method makes the best fireformed brass, at least with the one wildcat I used it on.

FWIW, above the charge goes a wad of tissue, slightly tamp it, then the Cream of Wheat, then in the case neck another tamped wad of tissue. The case is completely full of material. Point it in a safe direction and wear hearing protection.