I shoot mostly in pastures and fields. My biggest thing is just wanting to be able to clearly see my target at a few hundred yards..but at the same time I dont want a big and bulky scope on my ar...id like to keep it as compact as possible. I just struggle to imagine being able to shoot a coyote or hog on the run at 300+ yards or put a good clean shot on a deer at that distance with a 4X scope.[/quote]
Sometimes you need to overlook form and go with function. All but one of my rifles are used exclusively for hunting. I do like looks, but I must go for the kill attitude first, because that's what I want my rifle to do for me.
I think a 3-9x40 would be your best bet, and not be over powering to rifle size.. I know there's lots of very nice looking, compact/slender scopes out there, but here in Missouri, we have that wonderful thing--NOT--of the 4 point rule. A legal Buck must have 4 points(tines) on one antler before killing it. So you first need to see that Buck and count tines, and try to do this all under pressure, sometimes in what seems like Miliseconds. Not only this, but with a 3 power, a deer/hog can get within 10yds without a person knowing it, and with a good scope will still be very clear without overpowering the animal's size in scope, while with 9 power, you can feasibly see and make out an animal very well at 300yds. With good glass and 40mm Objective, it will bring in better light sources, that a smaller Objective scope has harder ability to do, and it lets you have larger "Field of View" that a small Objective just won't have. I use the 3 power when I hunt, but to see if that deer is a Buck or Doe, I crank it up to 9 power real quick, then it goes back down to 3 power. Reason being, is to see where/if animal runs and I need to trail it. If animal is 100yds and over, I keep it on 9 power to give better shot placement, and at that distance, a Field of View is enough, that I know if animal dropped in it's tracks or it up and bolted and which direction.
I own Nikon Buckmaster, Burris FullfieldII, Weaver Classic, Redfield Revolution, and these are all very good/superb glass, and will give many years of hunting pleasure, but their best quality is being able to let me see in darker hours where many animals like to move around in. Also, with a very good quality scope, you know your POI won't change round after round, due to better interior build parts, where all the problems arise from.. I do have cheaper scopes, but those are all on 17HMR or 22caliber rifles.
Also, like others have mentioned, good scope mounts are a must on any gun. I use Weaver Steel "Grand Slams" and Weaver "Quad Lokt" Rings on all my hunting rifles, but there's lots of good choices out there to choose from.
I will say however, my AR has a Bushnell TRS-32 Red Dot on it, but I use it as a Varmint/Pest rifle, and don't use it to bring home meat for table.
Del