ORIGINAL: thenuge15
Go up in your tree stand with all of your hunting clothes on and shoot at your target that you placed 40 yds out. If you can hit it withing a couple inches of where your aiming than you are probably accurate enough. However I would never chance this because a lot can go wrong at 40 yds.
Good answer. But I'll add that you should also use the broadheads you intend to hunt with and if you don't have a rangefinder, then you need to shoot at unknown yardages. Throw in a 4" group + 3-4 yards mis-judged and you have a wounded animal you may never recover.