Greetings, all. I've begun the research to build an AR-15. With tax season upon us, I've got some money coming and it's time to build. However, I'm quite new to ARs and don't have any idea what I'm really doing... So a few questions, some of which may be easier to answer than others. First, I wanted to make sure that 223 and 5.56 are actually the same caliber. I'd read somewhere that 223 will fire both, but I wanted to ask some experts before I make any final decisions. Second, I'd like to hear some opinions on brands. I was leaning toward the DPMS due to cost and good reviews on Midway and other sites, but would like to hear what you all have to say. Third, Both of the upper receiver assemblies I'm looking hardest at are called "slick side" and do not have the forward assist or brass deflector and dust cover. Do these really matter? Will I see any real difference not having them? Fourth, barrel length. This will be a plinking and fun shooting rifle, perhaps with some varmint hunting thrown in for variety. The two uppers I'm looking at are bull barrels, one is a 16" length, non free floating hand guard (which I know can be added later) and the other is a 20" with a free floating hand guard. Will any accuracy really be sacrificed with 4" barrel length? 20" Bull barrel 16" Bull barrel Fifth, is the bull barrel really all that necessary? I do want an accurate rifle, and I love the bull barrel look. Does it improve accuracy very much, or will a normal barrel function just as well? The lower I'm thinking about is an assembly, although I'm not opposed to getting a stripped assembly and building. I'm an automotive technician by trade, so I'm very mechanically inclined. But it will possibly be more cost effective to get the assembly, so that may be the direction I go. DPMS lower assembly I will be buying the upper first due to cost, I want to get the larger cost out of the way quickly, then I can save for a little while for the lower. I also realize that this is no top shelf build, and I really wanted to start entry level anyway. I also realize that a solid platform will give me the ability to improve in the future, and I would like to make sure I get that solid platform. Sorry about the long rambling post, looking forward to hearing opinions and thoughts.