Great episode. I'm looking forward to the third season and of course the finale next week.
As for the AR-15s/M-16s there are a number of reasons why you probably don't see too many of them in peoples' hands:
1) It's a fairly complex weapon that takes a bit of time to master compared to a typical bolt action rifle or even a 1911/M92 style pistol which are among the most "complex" handguns in popular use on the show and in reality.
2) If the "noise" factor is one to concern yourself with, the AR-15 is FARGING LOUD. For example, if you ever had to use one in a home defense situation, you might well wind up with permanent hearing damage.
3) Conservation of ammo is not exactly going to be easy with a full auto (M-16 military version) or even semi-auto (AR-15 civilian version) rifle and you'd better be able to get your hands on a ton of it if you want those rifles to be anything more than expensive hammers. It looks like all the ammo shops and whatnot were pretty much overrun and/or inaccessible by the time Rick met back up with the group.
On the other side of the argument are the facts that:
a) This is the South - there are a SIHTTON of AR-15s in civilian homes down there, I'd bet my own gun collection on that - so there would be a PILE of them in homes as well as a pile of ammo readily available.
b) Rick raided a police arms locker when he got out of the hospital and I can't remember if I saw any AR-15s or M-16s in that bag - (and I can't remember if he lost that bag of guns either).
c) The M4 carbine pictured in the above would be an EXCELLENT weapon for people on the move if they could master the operation of it due to the fact that that particular configuration is optimized for close quarters combat and multiple operators with the adjustable stock and so forth.
Either way, it's at least somewhat plausible that there are no or very few AR-15/M-16s in the group's arsenal for the time being at least.
As for the Shane, Randall zombie thing - yeah it appears that if you die, and your brain is intact, you will become a zombie in the environment now - this is an interesting plot angle because it accomplishes several things:
1) It stops all the concern about blood splatter and scratches and possible infection - thus letting characters fight and get bloody and not risk turning themselves as a result as long as they don't die.
2) It provides an opportunity for there to be a cure - which may not cure those already zombified, but which may cure those who remain so that they don't propagate the zombification.
Other spoilers - I was a little chagrined to see Carl point that 1911 at Rick (which he was doing before Zombie Shane stood up). That boy needs some serious attitude adjusting. I am annoyed at the death of Shane though as I thought his character was a big value to the story and that his decline into madness was partially reasonable, but in the end, was exaggerated in order to force the outcome in the plot. After his big dust up with Rick in last week's episode and after the whole talk with Lorie, I would have thought that Shane could have gotten it together. Of course, maybe he decided he wanted to check out and wanted to do so in a way that would let Rick live with himself for doing it and so he was being "crazy like a fox" to goad Rick into killing him. Maybe he just didn't want to live anymore with no chance of having Lorie and everything else gone to siht. Or maybe he was crazier than a sihthouse rat...
Additionally, now the group doesn't know about Randall's group that was about 5 miles from the farm since Shane died without passing that info on - I wonder if the zombies that approached the farm were the remnants of that group or if they were just other zombies not connected to Randall's group on their usual Zombie roam. This information provided a potential point of redemption for Shane. He had an opportunity to say "Look, Randall told me his group was and maybe still is camped about 5 miles from the farm, we gotta be aware and possibly go deal with that, and that's why I killed the little siht!" This would have been the thing to do for someone REALLY concerned about the safety of Carl and Lorie and the group... so maybe he was just crazy... Finally, I KNEW Randall was a fkn liar and still think they should have offed him earlier anyway.
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If ignorance were painful, half the posters here would be on morphine drips.
Everyone playing WoW knows everything about playing two classes: 1) their own and 2) Hunters