Just picked up a box of what is billed as an experimental caliber submitted by UK in the late 70s. I searched here but all I found was viewtopic.php?f=1&t=690&p=2983&hilit=4.85x49mm#p2983 on the subject. Are these legit? Any significant value? I have not opened the box yet but if they’re worth little I will add one to the display and sell/trade off the rest.