Orrbull48, I had Mike (DTech) build me a slow twist (1/14) upper specifically for shooting the lighter (35-55gr) bullets and it was a tack driver with the 40gr V-Max...They could be pumped to fairly high velocities and still hold together...It also shot the 50gr really well, but I had it built for shooting Prairie Dogs and causing some real acrobatics..so I stuck with the 40gr rounds...