The problem with novice trappers using jump traps is that they are somewhat of a directional trap. Directional in that the one single underspring rises high and has a tendency to throw an animal's foot upward unless the trap is positioned correctly, causing toe holds or complete misses. Jumps were invented and advertised as a trap for den entrances, so under those conditions one would know the exact approach of the animal so they could position the trap so that the rising spring would not be in the direct approach of the animal. When using them at sets other than trails sets or den entrances, one must have the experience to correctly anticipate the animal's approach and use correct guiding to ensure they enter the set from that direction. I have used them for years at dirt hole sets fox fox, coyote and bobcat without a problem. I always position them in front of the hole with the dog at 9:00 and the underspring at 12:00. The dog is guarded by sand ridges and possibly guide sticks to help prevent the animal from entering the set from the side and stepping on the dog while the trap springs causing a flipping upward of the foot causing toe catches. I guard the spring side with a little pile of dirt right in front of the hole. Blake & Lamb also made a #4 double underspring jump trap which I preferred as the double undersprings don't rise up so high when the trap jaws are closing. Oberto added a dogless assembly to this B & L trap and was my favorite coyote/bobcat trap. I like that they are light weight and set very flat. I never had an animal pull out or destroy these traps. A few big lungeing cats and coyote sprung a few of them somewaht out of shape but they would still continue to work anyway. I hope I have made sense here as this is a difficult subject to explain in words. In fact, i'm getting confused myself, LOL! Ace