T13 , depends on what you call Long Range . If I were just starting out , I would go with a 223 , 223 AI or one of the 20s based on the 223 Case like the TAC 20 or Practical . If Brass Cost is not a concern , maybe a 20 BR or 20 PPC which would also take you out a little further . For Ranges out to roughly 700 or 800 Yards , a 6 MM or 6 AI or 6 Dasher or 6 -284 or a Fast Twist big Case 22 . For 800 to maybe 1200 Yards , one of the big Case 6.5 MMs work well . All these Calibers have wide Bullet choices . For the last two categories , go Heavy and / or install Muzzle Brakes
so you can see your hits ( or misses ) .