M70 LA with remington .308 barrel

[BPTactical]

You sent me a PM on this that I dutifully totally forgot about. My apologies.
It is more than likely somebody's project rifle from CST or somebody just wanted a different build.
Early on the majority of Vietnam era rifles were off the shelf hunting rifles.
The Vietnam era M40A1 was adopted in 1966 and Remington based on the 700/40X action and was all Remington, built in the Ilion NY. 995 were built between 66-71.
They were tweaked here and there at Quantico until 76 when they were built with a heavy SS barrel by Atkinson(although they could not keep up with demand) and the receiver was clip slotted.
Hart barrels picked up the slack and are still used today, at least by the USMC. Some examples had Winchester floorplates after durability problems with the Al Remington pieces.
I don't have much info on the M24.
My dollar says Franken Beast.