http://cartridgecollectors.org/cmo/cmo10jun.htm
"
The O’Connor Steelhead, a.k.a. Ramhead, line of unformed rifle cases with tempered stainless steel screw-on bases were introduced to the shooting public in 1984. These were touted by their maker, the O’Connor Rifle Products Company, Ltd. of Edisto Island, South Carolina as a “totally new concept in handloading†that “increases powder efficiency and velocity.†They were sold in two different sizes; the .30-06 and the belted 7mm Rem Mag head sizes, with .280 Rem, .222, .308 and .375 H&H magnum “coming soon.†The cases were also available in .50 BMG on special order."
I think there were others before.
Stryker60