This will be my first AR. I am looking into buying an AR15 for competition shooting. The farthest we normally shoot is out too 600 yards. I have a bolt action in 308 that is very accurate, but I am wanting too try out 5.56 semi-auto. I am keeping the price for the rifle in the $1500 range. The DPMS Mini SASS has caught my eye as well a Stag Arms. They both have 18in barrels which from what I have read is sufficient compared to a 20incher. Any suggestions or pointers from some one that has been here and done that.