I have a Browning A-Bolt .300 Mag with Boss and 5x15x50 B&L scope. I have it sighted with Barnes TSX 168gr in front of 74.9gr of Reloader 22. It is sighted dead on at 300yd. What do y'all consider long range. I have been trying to find target knobs to no avail. I checked Stoney Point but...