Standard US bayonet from 1986 on.
USGI 4th generation 4-
Phrobis an Oceanside California Research and Development Company designed the M9 bayonet and secured the M9 bayonet contract specifications. Phrobis then licensed the design and production to the Buck Knife Company while retaining the patent rights. Buck manufactured the first M9 bayonets for Phrobis in 1986.
The contract was for 315,000 pieces with a couple of 60,000 unit options at military discretion. Buck continued to manufacture the M9 bayonet under subcontract for Phrobis until 1989 when the contract was terminated for mutual convenience between Buck and the Phrobis. I have read that Buck had a falling out over the last payment due on the contract and ended up settling on buying Phrobis including all product rights to the knives that they had developed, including the technical data package for the M9.
Buck made about 325,000 bayonets in the late 80’s and early 90's for the Army with only the first 1200 having any reference to Buck on the stamp. The earliest bayonets were marked with the date code for 1987 ">" on those until they were directed to stop doing so. During the Army contract, there were quite a few commercial versions sold by Buck and they had the stampings of Buck on one side of the blade and Phrobis III on the other side of the blade. Other commercial M-
A second contract was awarded to Lan-
Ontario Knife Company
USGI M9 manufactured by Ontario Knife Company, with Bianchi compatible scabbard.
Third Contract Ontario M-