The .308 caliber (7.62 Military) round has never been called "Kate". I think what you are talking about is a rifle with the nickname Kate.
The rifle is a Tactical Operations Bravo - 51. It is a highly accurized version of the marine M-40 and Army M-24 sniper weapons. The weapon is capable of printing .25 MOA or to the non-shooters out there, can but bullets in 1/4 inch groups for every 100 yards in distance.
EX: If a TRAINED sniper shoots a target 400 yards down range the rifle is capable of putting all rounds in a 1 inch group, 2 inches @ 800 Yards etc. out to 1000 yards.
As with most things, you get what you pay for and the rifle is very expensive and is usually found in Police SWAT and some military Spec. Ops. Units.
As far as I can determine the name "Kate" was given to one weapon, the operator of the Sniper Central website was a military sniper and had named his rifle "Kate". When he left the service and had to give up "Kate" he purchased a Bravo-51 and called it KATE II and mentioned it on his website. It took off from there. It is common for rifle shooters to name their rifles. Daniel Boone called his "Tick Licker" for instance although most name them after women.
Hollywood is responsible for people thinking all .308's or that there is a Kate model out there because when they killed off the character Kate in the NCIS episode "Kill Ari" Gibbs said snipers who used a Bravo-51 called them "Kate". The Gibbs character was a sniper in the Marine Corps.
Hope that helps.
Here is what a Bravo 51 looks like: see link below-
It uses a 30 caliber or .308 inch diamiter projectile. .308
Negative, 308 is a 30 caliber bullet and 30 doesn't fit into 25.
a "308" measures .308 inches while most 30 caliber ammo measures .312 inches. Strange as it may seem both are classifies as 30 caliber ammo.
30 caliber = .308 of an inch = 7.62mm
Yes it is, it uses a .30 caliber bullet which makes it a 30 caliber
The 308 caliber guns are more expensive than 5.56 assault rifles.
Marlin makes a .308
A lever action rifle chambered in .308 Winchester.