Last September, I get a guy (29 Yrs Old) in the shop wanting me to order him either a 7MM or 300 Ultra Mag because he wanted a gun that would "flatten whitetails on the spot". I don't recall what exactly he had been using, but I think it was an old 30-40 or 303. Anyway, he wanted my thoughts on the 7mm or 300 ultra. I told him rather honestly that I'd been hunting deer for round about 30 years and I've killed a bunch and that in most cases a deer will run 30-75 yards even with good hits. I've seen them drop in their tracks sure, but realistically they will go a little ways. So, we got to talking about what gun probably had the "best" knockdown power. Again, just my opinion, but I told him my dad used a 350 Remington Mag back in the 70's and 80's that I could remember dropped a bunch in their tracks. I told him if I was going to buy a rifle solely for "knockdown power" on whitetails, I'd go with a 350 or 35 Whelen with 200 or 225 grain bullets. I told him rather than buying a new ultra, I'd sell him a used Whelen at a decent price and give it a try. Well, he didn't buy the Whelen, but ordered in a new Remington 673 in 350 Remington Mag. The guy came in yesterday and was telling me what a great gun the 673 was and how it totally "flattened" two nice bucks this past season. I told him I was happy and glad to be of help, but that got me thinking about knockdown power.... if it really exists. I've used a 700 BDL in 30-06 for years and see no reason to change.... I don't mind walking the extra few yards to pick up my deer! I've seen deer shot with pretty much everything through the years and would say my vote for knockdown punch only would be the 350 Remington or 35 Whelen (taking into consideration recoil, cost, etc.). What do you all think?