X Designation on 5 tons

[Gamagoat1]

Can someone (Maybe David Doyle) explain the X designation on the series 809 5 tons.
Like the XM816 etc.

 

[jwaller]

I asked this same question when I got my 809.

I remember it being something about letting the trucks into the system before they were fully tested and approved.

 

[BKubu]

I believe the X means that the truck was put into production before it was accepted as standard...just what JWALLER said.

 

[ida34]

When I was an armorer in the Army I had a rifle designated XM16E1. It was the experimental trial version of the M16A1.