Love my SWFA SS 3-15, would love to get an HD 5-20 for my new 6.5 Creedmoor.  I just don't understand why you don't make it in MOA?  Here in the good ol' US of A we learn imperial.. yards and inches.  I don't think in centimeters and meters and after 44 years I don't plan on changing.  I'm slapping a budget Athlong ArgosBTR on it until I save up enough for nice glass, so you have some time to correct this oversight.

We'll keep it simple then.  1mil = 3.6" per 100yd.

MIL/MRAD and radians have nothing to do with centimeters and meters, it's an angle measurement, just like degrees.
There are 2*pi radians in a circle, and there are 1000 MIL (milliradians) in one radian.

MOA (minute of angle) is just 1/60th of a degree.

For example, a 10deg angle is 600 MOA
The same 10deg angle is .175 radians, or 175 MIL

They work the same, use whatever linear measurement you like.

Exactly right. Back in my scope selling days, I always had to explain this to people. MOA is not 1 inch at 100 yards, it is 1.047 inches at 100 yards. It is just a convenient coincidence, not a measurement driven by the imperial system. If so inclined, the math could be done easily to determine a system where in one "poke" exactly equals 0.25 inches at 100 yards, or whatever substension you want.

Thanks for the replies guys, I've actually been studying up on this the last week or so and think I might actually make the switch.  I'm just starting out in long range precision rifle shooting and everyone talks in Mils, so I guess that's where I need to be.

Im a MOA shooter and so is everyone in my group, about a dozen of us. With that being said most of us have Vortex because they are about the only one that supports both systems. I too would like to try a H-D SS but Im not going to switch to mils for it...