The distance you're shooting is what I would consider max. I have however shot 55 yard with #5 and took a turkey, open field shot. I too had to step on the bird to finish him off. Last year I did I shoot close to the same distance and took another bird. That 1 shot didn't total kill that bird also. All shots 40yrds and closer, 1 shot dead bird. So I guess what I'm saying is, yes I'm happy with Hevi Shot #5.
One time I had a tom come in from behind me while I was aiming in the wrong direction. I had to hold my gun sideways and aim off to the side of the head at 8 feet. Killed the bird with 3 pellets in his head. Only shot I had and the bird had busted me.
The last few years I've been trying to fill 1 tag with my bow and 1 with my gun. So to me its been more of a challenge taking that first bird of the season with a bow vs the 12ga 3 1/2 #5 on the second bird.
Happy hunting.