How much pressure to fireform brass into shape?
At approximatly what pressure does brass move to fill out the chamber when fireforming? I fired 5 rounds today for which I had formed from 348 win into 41 swiss, when I fired them the brass came out looking exactly like it went in? I would have expected the shoulder to move forward and fill out the chamber, What gives?
My border collie is smarter than your honor student.
My border collie is smarter than your honor student.
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i use 348 brass to make several different cartridges, several of them take a pretty good push to form, anealing the cases helps, i also use shotgun bb's instead of cornmeal , that puts enough of a load on the brass to pop it on the first try 0 -
I loaded 12 grains of 2400 under a 340 grain bullet. the neck had been anealed... they all went bang, but no shoulders moved. I figured that would have made enough pressure to form the case. I really don't want to make up proof loads for a 130 year old rifle even if it looks like new.
My border collie is smarter than your honor student.0 -
i like unique powder for fireforming , in the 348 case i use 15 grains 0 -
I used to form 219 Ackley Improved cases from 30-30 & 32 Special
using 2400 powder and no bullet or other filler. The charge was about 10 grains if I recall. The barrel is pointed up vertically to keep the charge at the base of the case and fired. The shoulders moved forward and were sharp.0 -
The best way to change brass for a new caliber (wildcat) is to seat your bullets WELL INTO the lands. Load the cartridge with a medium charge of the fastest powder in the manual for that caliber, and light it up. The faster burn rate,..and subsequent shorter pressure curve will form the brass while the bullet is still leaving the case.
Seat em deep in the lands,..and light up a fast powder. I always use a powder listed for the PARENT caliber!!!! The pistol powder method leaves what I feel to be an unaccpetable margin for secondary detonation due to the small amount of powder used. If the powder charge is small enough to lay in the bottom of the case when layed on the bench,..and not reach the level of the primer (1/2 case full from case head to bullet base) then a detonation of the entire charge at once can result in a pressure spike immediately,..which can damage the gun and the shooter.
why chase the game when the bullet can get em from here?....
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I've been using Unique for years to fireform 6.5 Swede to 7.5 French. I use the 15-17 gr. of unique under cornmeal method with a slight adaptation; I use a plug of sealing wax to fill the neck over a small ball of cotton (pea sized) to keep the wax from getting congealed with the cornmeal. This seems to improve my case shoulder shape and the fairly thick brass of the 6.5 is a bit of a tussle to move ussually. I rarely use a bullet in the lands and oddly enough I've always had good luck with this and other conversions. You still have to run them through the sizing die afterwards but it seems a small sacrifce to avoid hurting that old gun!! Good luck...hope this makes sense and or helps!
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richbug, I had the same experience as you in trying to fireform .348 brass to the .41 Swiss caliber. I was using a 240 gr. bullet over 12 gr. of Unique. I THINK now that maybe I should have annealed the case back below the shoulder as the .cut-off .348 brass is fairly thick. Anyway, I gave up and bought some formed brass from Buffalo Arms as the cost in time and wasted brass was getting a bit much for what I was getting in return. Emery
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