No it is not. I don't remember where or when I copied the plan but if I ever do build another, it'll be this one. The first attached picture shows my daughter shooting my under hammer. She shoot it about three times and declared that the gun was hers from now on. I do miss that under hammer. The second shows my granddaughter shooting the under hammer. The bench is one I made using pipe legs that store under the top and it has three legs so it'll set up on uneven ground.
doggoner