Hey y'all, so I've got my predator hunting/build something itch scratched with a 300 blk out rifle I built the lower for from an 80%. I really enjoyed the whole process and think I'd like to step it up to a full rifle. I'm thinking 6.5 grendel for deer/potential hog hunting and the ability to shoot out to 800-1,000 yds. I know what I want from the lower, but I'm clueless as far as the upper. I'm a poor college student so I want this to be an economy build except for the barrel, trigger and optic. In my very limited knowledge these 3 things should be the only spots I really need to splurge to get a good shooting gun, right?
I don't plan to have this complete till late next summer so I'm in no rush. If I go slow I can do things right, catch stuff on sale and save as much $$ as possible. My number one question is about the barrel. I'm thinking 20", but is a 24" gonna be worth the extra price? Like I said I'm poor so is building the upper the most economically sounds option, or should I get a completed upper? If I get a professionally done completed upper would that be more accurate?
So what barrels or uppers should I start looking for? Any other advice, things I've clearly got wrong or haven't thought about? I'm doing a lot of reading but I still don't pretend to know much at all so any advice is appreciated.