I talked my dad into an AR, being a ruger man he purchased the very same model. His needed a little trigger work, his had a good 10.5lb pull out of the box. After that was he loves it.
This thread cracks me up. Everybody in Indiana loves pistol carbine, because that's as close to a real rifle as we can get for hunting. If the high power law would have passed we all would have hunted with high powers this year. Pistol carbines are fun, but they don't compare to a real rifle...
Anderson upper and lower 40 each at Midwest gun exchange find a good barrel on ebay less than 100 shipped. 40$ for lpk, 20$ for a mil spec trigger Anderson rifle .Com
Their good. It's a great low cost upgrade. Far better than mil spec handgaurds not as good as a quality key mod rail but they don'the cost near as much.
I have found that twist rate doesn't really mean all that much. My best shooting AR has a 1/7 twist rate and it loves 50gr bullets. Shoot the heavy stuff and the groups open way up.
You could build 2 cheap AR's for 1000$ or one really nice one. But that's today, if your gonna build one do it soon. Also you will need to invest in some tools to do it right.
An over looked part here is the gas system. Most times ar's are over gased due to extra large ports on the barrel or too short of a gas system. For an 18" barrel you'll be looking for something with a mid length gas system not carbine length. The carbine length would work but your recoil...