Sendero, you can't get too much trigger time.
We owe it to the animals we hunt to be able to put them down as quickly, cleanly and efficiently as possible.
Shooting performance is a perishable skill. Meaning that it diminishes very quickly without practice.
I don't care if you or someone else is a currently active or ex SEAL, Delta, Force Recon, or Scout/Sniper, you have to keep shooting to stay on top of your game.
Typically, shooting "MOA" is the accuracy standard. Meaning 1" group @ 100 yards, 2" group @ 200 yards, etc. I always like to shoot a 5 shot group to get my results. Others prefer a 3 shot group.
If you want to shoot out to 300 yards, then you might want to think about shooting at least a 3 shot group 3" or less at 300 yards. And I like to shoot at the range like I'm going to shoot out in the bush. Usually off my Harris Ultra Light, backpack, etc. You won't have the luxury of having a nice bench to hunker down on when it's time to shoot.
Know your rifle/caliber!!!!! Check ballistic charts, get all your dope on your scope figured out. If you use a rangefinder, take it with you when you shoot. Try it out in fog too. Some RF read in fog and some don't.
300 yards is not a huge distance. But, and 35 mph wind going left to right of you can move that bullet a lot. Good luck!!!