For a .308 you would be limited to these models :
TA11-C 3.5x35 Donut BAC
TA11-E 3.5x35 Flattop Reticel BAC w/ flattop adapter
TA01-B 4x32 standard reticle
The TA11-E is really designed for an AR the reticle lines up with the front sight post.
The TA01-B does not have a fiber optic day time illumination reticle (BAC) and has the basic bullet drop reticle. It is 4x and smaller than the 3.5x.
The TA11-C is the coolest of the three. It has a red donut that lights up in the day time with the help of the fiber optic (BAC). Then below it is the bullet drop reticle.
You will need a TA51-W to adapt it to your HK mount.