Yup, the crosshair thing is the NATO stamp and usally loaded with/as the M855 62 grn FMJ for international shippng/sales as NATO ammo. The LC and the 2 digit year are close together with the crosshair between them, they also have a series of dot's designating a machine so if there is trouble they can go back and find it.
There is another different looking head stamp for the M193 55 FMJ. These have the L-C-0-3 set like a clock at the 12-3-6-9 o'clock positions.
Like Bigeasy said they have a smaller capacity, this is good we can reach max velocities with less powder. For all practical matters they're the same.
But when it comes to splitting hairs, each year class does have a different water weight capacity thus a different volume. You should split'm up and load'em by similar year stamps untill you have a chance to prove a good load in different stamps.
Might as well remove the volume variance from the load development equasion.
