wen you say .308 x 1.5 = is the 1.5 is the lengt ov the brass
they ave 3 caliber y know they have close to this lengt
1) the .30BR =is parent case is a 6br nek up to .30 very effective in score choting
2) the .30x47= is parent case is a .308 savage modifier
3) the .30 cannuck = is parent case is a .308 savage modifier
the 2 last you se some chooter use this in IBS match in U,S. and in QUEBEC