Search:

there is no half cocked, its fully cocked as soon as you open the bolt.
its de cocked when you hold the trigger and close the bolt(don't recommend) or fire a shot.
safetys work unless some twat has...

No because you shouldn't be slinging the rifle with one up the spout.

Sent from my GT-S5360T using Tapatalk 2

Use the safety or an open bolt with your thumb on the bolt.

I wouldn't bother with a suppressor on a tops rifle.
suppress the 223 instead.
Pretty much any of the long action calibers will do what you want, magmum cals will stretch your effective range a bit...