Ar pistol trunk gun concerns?

[LRRPF52]

Ok, so I'm trying to think threw the pro's and con's of an AR Pistol,...Never held one or shot one so trying to anticipate uses before I start spending money on components. I don't know if I would ever use it for the reasons most state. And that building a 16" carbine as light as possible who be sufficient for my needs? Which is primarily hunting and varmint/predator control.

Those of you that say you use it as a "trunk gun"
1) How do you store it in the vehicle?
2) are you concerned about accidental discharge? Floating pin on a locked and loaded firearm bouncing down the road?
3) We have had vehicle break ins in my area, do you keep it in 24/7 or only in certain situations? remove it daily?
4) do you consider it a primary or secondary option as a defensive weapon?

Those that store it in a pack for concealment/transport how easy is it to access?

any pictures of your soulution for secure vehicle storage would be appreciated.

Thanks in advance.

Gents, let's keep all responses limited to the OP's questions, not political or other derailing topics.