As far as the bigger is better deal :

I shot a 185lb buck at about 75 yards with a .6mm Rem and dropped him dead in a field....few years ago!! I took a guy hunting and put him in the same stand 2 days later and he killed a 130 lb buck at the same apprx. range with a .300 mag that ran 200 yards or more !!

You can argue about all you want about what is better or not .........but I shot mine right in the shoulder and he shot his back in the liver !! You could not prove to me that the .300 was better at killing that day !!

By conincidence .........same field this year a guy shot a spike that weighed 110 lbs with a 30-06 180 grain bullet that went right through the rib cage and made a small entry and exit............deer ran 100 yards or so before going down and very little blood to trail !!

So I guess I could argue that the .6mm is a better killer !!

But I think it's the shoulder shot that made the difference !!