Mr6pt5: I have friends here in Montana that routinely use the 204 Ruger to harvest Whitetail Deer and Antelope with.
And if you castigated the 204 Ruger as just a Gopher cartridge then you have learned a valuable lesson (one I learned LONG ago!), don't knock something til YOU have tried it!
I personally have used the 204 Ruger cartridge since it was brand new and now have 4 (four) Rifles in this amazing and versatile round!
This cartridge has performed spectacularly for me on all manner of Varmints from Coyotes on down to Ermine!
Also included in my 204's list of cleanly harvested Varmints are Badger, Porcupine, Fox, Rock Chucks, Ground Squirrels, Raccoons, Jack Rabbits, Skunks, flying Varmints and feral cats!
The 204 Ruger cartridge was designed to be a Varmint cartridge and it performs wonderfully there - but it also can be used for other things as well.
Speed kills!
Long live the 204 Ruger.
Hold into the wind
VarmintGuy
P.S.: I have not had a chance to harvest any Turtles as yet with my 204's - I have Hunted them in the past for a couple of ranchers that needed their fish ponds "protected". The 204 should indeed perform well for this task - like 204 Ruger mentions, keeping in mind there should be a high bank or cliff for a back stop!