Do you mean they (thinner blades) get dull faster,blade quality aside,when hitting hard tissue?
Joe.
Thin blades will get dull sitting on a shelf in open air add to that taking them out and putting them back into a quiver they loose their edge fast. Most people sharpen their heads at the begining of the season and think thats it they dont need to be re-sharpened during the season because they have not been shot.
The thicker the blade the longer they will hold their edge plus a thick blade will not slide along bone they will smash through it. I have some Broad Heads here that are .043 thick that have been shot into a Jellow Jacket a lot and those heads will still shave hair, unfortunately I cant say the same for thin blades.
btw, i shoot the lighter head for more speed.
Speed is not everything I can shoot in the high 280's with my set up but prefer heavy thick blade broad heads with extreme FOC for better flight stability (specially if there is a cross wind)and penetration. I want the front pulling the arrow not the arrow pushing the front as that is what washes off your momentium which we all know is what gives us the best penetration.