Brass Variabilty
Posted: 02 Mar 2019 10:33
I am not telling anyone something new when I say that all brass is not made the same or that it changes over time. Like many I have cases that are brand new, over 50 years old, fired and sized from 1 to 20 times and from many manufacturers of cartridges. Of course some ammo makers buy their brass from others and it may be differ depending on supplier. Some have been annealed once and others several times. Some are neck sized most of the time and others are full length sized all of the time. Some have been fire or cold formed or both from another calibre. While conventional wisdom says that my mil surplus brass is thicker I have found commercial brass that is heavier when case weights are compared. I don't have the equipment to measure brass chemical composition but the accepted 70/30% copper/zinc ratio is apparently not necessarily what you get. Read this article for more information.
http://bulletin.accurateshooter.com/201 ... trometers/
All this to say that I find this variation very interesting and have experienced its effect on reloading in a number of ways.
- Case stretch
- Bullet grip
- case splitting
- Primer pocket loosening
- Bullet seating resistance
- resistance or affinity to cold and fire forming
The discussion on Starline brass problems experienced by some here reawakened my interest in this subject. Why are people experiencing case failures that point to brittle brass? I haven't experienced any case failures problems but I only use their brass for 45 Colt. I have had some minor issue with bullet grip. Is it something in their manufacturing process or the chemical composition of the brass? Some of my 45 Colt brass is put aside for annealing. It will be interesting to see how these compare to new cases.
Edited to correct ratio in the first paragraph of copper to zinc in C26000 Cartridge Brass.
http://bulletin.accurateshooter.com/201 ... trometers/
All this to say that I find this variation very interesting and have experienced its effect on reloading in a number of ways.
- Case stretch
- Bullet grip
- case splitting
- Primer pocket loosening
- Bullet seating resistance
- resistance or affinity to cold and fire forming
The discussion on Starline brass problems experienced by some here reawakened my interest in this subject. Why are people experiencing case failures that point to brittle brass? I haven't experienced any case failures problems but I only use their brass for 45 Colt. I have had some minor issue with bullet grip. Is it something in their manufacturing process or the chemical composition of the brass? Some of my 45 Colt brass is put aside for annealing. It will be interesting to see how these compare to new cases.
Edited to correct ratio in the first paragraph of copper to zinc in C26000 Cartridge Brass.