The " stock " release would be for " leftys " when using your index finger.
The " index " release would be for " rightys " when using your index finger.
If you are a right handed person (like myself) then the index finger release makes it so you don't have to move the marker at all to release the mag.
It's amazing how much easier using a Tiberius becomes when you can keep your aim on someone and still change your mag =)
I think it's the #1 purchase for any Tiberius owner. Well I guess if your right handed =)
__________________ I only need 1 shot, no hopper, and your out!