The gophers must be about the same size of prairie dog pups which are about 6-8 oz when the come out in the spring. I use a 17 HM2 for shots out to about 80 yards, a 17 HMR for shots for out to about 150 Yds . A few years ago I got a 221 Fireball for shots out to about 225 yards, but this year I have gotten a 17 Fireball rifle with a 6-18 X scope and have made hits out to about 275 yards. I get more shots when I use rifles with a low muzzle blast. With the low recoil I can see the bullet hit them. I have use a 204 Ruger for longer shots. Over the years I have tryed out the 17 Rem, 22 Hornet, 221 Fireball, 223 Rem, 22-250 Rem, 220 Swift, and 243 Win on prairie dogs but now I like the little 17s and the 204 Ruger for small varmints.