Fire forming rifle brass without a bullet?
- Thread starter TrevorF
- Start date
I have tried the TP and COW method years ago. Never got a fully formed sharp shouldered case by the a fore mentioned method.
With a new barrel cases are fire formed with a moderate charge of the powder I will be using with a Hornaday BTHP, an accurate load can be had so practice is not wasted. The result is a fully formed case.
why FA
With a new barrel cases are fire formed with a moderate charge of the powder I will be using with a Hornaday BTHP, an accurate load can be had so practice is not wasted. The result is a fully formed case.
why FA
True.
When I fire form 280 Ross or 340 Gibbs, the first firing with cream of wheat over 12 grains of 700x powder does not quite get the case to fully formed dimensions. One must stoke the cases with a moderate load of powder (eg. 50 gr of IMR4350 for the 280 Ross) behind an appropriate jacketed bullet for the caliber. This will iron out the shoulders and any other wrinkles quite nicely. Then anneal, trim to length and reload with your favorite hunting or target load.
- Location
- Western Manitoba
I annealed all the 7mm Mag cases first. Don't get all perfect, but opens up enough for sizing ball to enter case mouth. Check out the SAAMI case dimensions - as Mag cartridge bore gets bigger, the neck gets thinner - .264 Win Mag has .034" neck walls; 7mm Rem Mag .031"; 458 Win Mag .023". I don't know, never seen it done, but would not be surprised if all of the standard length mag cases start from the same size slug, undergo the same drawings, then necks and shoulders formed and sized back down to finished size.
My experiment is 308 Norma mag. I tried 7mm mag, 338 win mag, 358 Norma mag sized then filled with Trailboss and a 180 gas checked cast bullet. Fired at a target. Non of them measured to the max case length, or even to the trim length, just short of it. So 300 win mag pushed the shoulder back and trimmed to length, a little crinkling at the neck. Loaded with Trailboss and the Gc cast bullet, and fireformed. It's o.k.. Then tried 300 H&H sized the easiest, used a tubing cutter to trim back the excess neck, then trimmed in a case trimmer to max case length, then Trailboss and bullet. Worked real well, except when the tapered case walls of the 300 H&H were blown out to the 308 NM chamber the neck was pulled back in .015 inch. Too short for book measurement. Now 300 H&H sized, trimmed long slightly into the rifling.10 grains Unique, fill case with COW, top with melted wax. Fireforms perfectly. Now trimming the next cases 15 thou longer than max case length with Unique,cow,wax to see if the fireform to the exact max length. All cases mention will hold and shoot bullets. Trying to get book specifications. This is a lot of fun, and learning things along the way. Initially i didn't want to pay $170.00 plus tax for 50 cases. Lol.
- Location
- Western Manitoba
To 65cutlass: I had formed up some 7x61 Norma Mag brass from 7mm Rem Mag brass. Might have approached it differently than you did? I knew the 7mm Rem was longer than needed - so I ran them through the seating die (without the stem) to start forming the "new" case. The guy I did this for got a nice Sask farmland moose that fall with his rifle and these loadings, so they worked!! I did a posting about it: https://www.canadiangunnutz.com/forum/showthread.php/1526794-Adventures-in-case-forming
FIRE FORMING 220R TO 6 PPC: I use the COW method Bullseye 15gr cream of wheat to neck and Tp on top.
Works well and the fact the shoulder is still slightly rounded makes very little difference if any in accuracy on first loaded round.
Works well and the fact the shoulder is still slightly rounded makes very little difference if any in accuracy on first loaded round.
