Isn't it funny...

[Dropship]

As a - ahem- computer wargaming champion under my fighting name 'PoorOldSpike' I can assure you that it depends on the angle of impact, velocity and calibre etc as to whether a slug would penetrate a book or wooden fence or flak vest etc..

Ain't you just the virtual bad-ass. Why don't you hold a buy-bull in front of your face a let someone fire a real AR15 at it..

If you mean the 5.56mm AR15, I wouldn't have one as a gift because 5.56mm is only a wimpy .22 inches calibre!
On the cyber battlefield my weapon of choice is the MX 6.5mm with underbarrel grenade launcher, and sometimes I take a Navid 9.3mm machinegun just for a change. It can't usually penetrate armoured cars, but I like to shoot out their tyres to make them lurch to a halt, then cut down the crew and passengers when they jump out..
PS- another of my wargaming policies is- "Never fear to use heavy weapons and overwhelming firepower, let the fear be your enemies"..