RE: anybody had experience with these "varmint" rounds?
About anything will blow a hole in a coyote pelt if you are using a expanding bullets.Barnes are pretty exspensive yot'e fodder.
Go with a full metal jacket bullet.They work great,aslong as you don't hit a bone.
Buck shot works well with in 40 yds,I have used # 4, 3 inch turkey loads on yot'es under 40 yds and kills them dead also.