Re: Will I be able to reach out to 500 yards?
No offense meant here, but it sounds like you would be wise to take a long range rifle course with your RUM. After some training & practice at long range, changes in Density Altitude won't worry you. Also, it never hurts to have a couple dope charts handy for appropriate DA's for when (not if) you're battery croaks & your ballistics app ain't there for ya ;)
Technology is great, but elk country is hard on it.
These other guys know a lot more than me. I'm just throwing this advice in because it helped me.