sirs, bobby hart has awilcat round that uses the 7 mm remington case as a base.it has the shoulder blow out to 40 degrees and gains some more powder space. my ? is is the shape of the shoulder increase the efficencey of the case to gain more veloicty?it picks up i beleive 3 or 4 more graines of powder also. the way i look at this is i can use 7 mm mag s iif i have to veses say the 7 mm on the 300 winchester case.he has told meit will gain about 100 fps with a 175 grain bullet and do 3450 with a 150 grain bullet. any thoughts on this?also does any of you own one of these / GARY B.