Just got a .585 GMA Express. What does “GMA” stand for?
“Granite Mountain Arms” , it is a proprietary cartridge developed by that factory that makes custom rifles.
You can find their website on the web
Pivi–Thank you for the quick answer.
Yea Ron, Granite Mountain Arms is based right here in Prescott Ariz.
In fact the mountain “Granite mountain” is about 5 miles south of where Pete lives in Williamson Valley.
My 2 cents again