I have several ar uppers in different calibers, and for pure fun factor the 16" 7.62x39 upper is unbeatable. Lots of impact on close range targets, deer, hogs, or steel, but it kinda falls on its face outside of 200 yards. I also have a few 300 blk that I love, but the x39 will throw a much heavier bullet faster with careful handloading. I load 308 bullets in 150 grn and can get around moa at 100 vs 2moa or more from most other x39 guns excepting my cz527. I really like the 7.62x39, it gets a lot done for very cheap. It's not a 30-30, but you can double tap with a semi auto. My son commandeered my upper and mags for his first ar, so I need another one...