Its called the 7mm Allen Magnum developed by Kirby Allen of Ft. Shaw MT. its basically a 338 Lapua mag. necked down and improved with a 37 degree shoulder
here it is compared to a 7mm rem. mag
It will run a 160 nosler accubond at 3600 fps, and a 195 Berger at 3300. Imagine a bullet with a BC of around .8 at that speed and your looking at an almost laser flat trajectory.
This rifle has taken over 60 whitetails by an untold number of shooters with the closest being 302 yards, out to 1,350 yards. at 600 to 800 yards its almost boring, and if you have never witnessed a impact on a deer at that speed, it is incredible. I think the first 26 deer I shot with it never moved after the impact except to fall down.
my hunting load is a 160 nosler accubond in front of 105 gr of wc872 powder which is a mil-surp powder designed for the 50 bmg and the 20mm Vulcan cannon. It is the flattest shooting 7mm hunting rifle in existence.