[stalkingbear]

To begin with,let me say that asking the "best" cartridge for deer is akin to asking the most beautiful woman or the best cook-there is NO 1 answer qualified for everyone and every shot situation! Now,that having been said,I've killed deer with everything from maglite to .22 pistol to claw hammer (finishing off road injured/roadkill) all the way up to .458 win mag (buddy wanted me to shoot his pet .45/70 level loaded on deer to test performance) and 1979 peterbilt. Also,I've been hunting since the late 60s,been gunsmith/custom rifle builder and part time guide,killed too many to count,as many as several per year,as well as watching many other kills 1st hand-both in home state and others. Not tooting my own horn-just background. Naturally I've developed some pretty strong opinions along the way as to what consitutes the perfect size caliber/cartridge for deer in different given shot oppertunties. What I've concluded is every rifle is somewhat of a compermise. By that,you want to have enough bullet weight/diameter/velocity to be able to penetrate deep enough to reach vitals from any reasonable direction/angle at the same time having decent ballistic coefficent and sectional density, while not having excessive recoil resulting from "excessive" weight/velocity/diameter bullet. Yes,I realize there's been thousands of deer,if not millions,cleanly killed with .22 centerfire,243,and ,25 caliber bullets but these smaller sizes depend too much on perfect terminal preformance from bullet and lack a little weight I personally prefer for optimum results accross the board. Also .30 caliber and above is really overkill as firing bullets with good ballistic coefficency with same speed as smaller,slightly lighter bullets WILL produce more recoil than neccesary for deer.
In MY screwy opinion,bullets in the 6.5mm,.270,and 7mm diameter falls in the optimum diameter for deer size critters. Of these,the magnums are more than needed for 98% of normal hunting situations and shot oppertunities so we'll concentrate on the "standard" cartridges. The 6.5mm is VERY underrated in the united states and bullets of that diameter offer excellent ballistic coefficent as well as sectional density. Among factory loaded 6.5 cartridges,the 6.5x55mm,.260 remington,and 6.5x284 represent the best of class for whitetail cartridges in that diameter.
Next step up is the famous .270 championed by Jack Oconner-forever the dean of outdoor writers and introduced in the 20s so it needs no introduction by me.
Now we're getting into my favorite of all time caliber for deer-the 7mm. I'm a HUGE fan of 7mm bullets fired from whatever cartridge you can think of (within reason). The 7mm diameter offers the most advantages of all calibers for deer-enough bullet weight/diameter/ballistic coefficent/trajectory in standard cartridges without producing excessive recoil. Of these are the 7mm08,.284,and the .280. The .284 was the 1st non belted "short magnum" without the name,and almost dead(even tho I still LOVE mine),so it's pretty much out of the race. That leaves the 7mm08 and .280. Either 1 of these will cleanly kill any whitetail EVER to walk the earth,and at any reasonable distance. It's hard for me to choose between the 2 but I lean heavily toward the 7mm08 which is simply necked down .308 as the "perfect" whitetail cartridge,and usually extremely accurate. If you need more firepower than the 7mm08 provides,either you REALLY like recoil,or you're shooting game at long range-to me,that's NOT hunting. The .280 is a natural in 06 length actions,has about 100-150 more fps than the 7mm08,and is a mighty fine cartridge for allround game as it easily accepts any 7mm bullet from 100 gr all the way to 175 gr.
There's NOTHING wrong with .30 caliber cartridges,just that In my opinion they're simply not needed on whitetail size game. The .308,or 7.62x51mm in military jargon,offers capibility for excellent accuracy,more than enough velocity/energy,and is still mild in recoil.
Finally we come to the king of versaitle cartridges in america,the 30-06. This cartridge has been on the job over 100 years in military and sporting chores and is better today than it was when invented back in 1906 (due to improved powders and MUCH better designed bullets). For the man who wants 1 rifle to do it all,the 30-06 is truly the most versaitle cartridge ever used,offering bullets in 110 gr to 220 gr. BUT,in my opinion,it's overkill for whitetails.
The new .338 federal,while being a fine cartridge for elk,but is too big for whitetail only,and in my opinion,still overshadowed by the older .358 winchester-even if it isn't as popular as it should be.
The .35 whelen has much merit for the man that's going to be hunting elk as much as deer,and will drop anything in north america within 300 yards,without much more recoil than the 30-06,but is too much for deer alone.
The various "brush" short range cartridges such as 30-30,.35 remington,.44 magnum,.444 marlin,and 45-70 are great within their intended use but lack velocity/trajectory for use allround. Also,it's been proven MANY times and times agian that ANY cartridge meant to be shoulder fired and within reasonable size/power CANNOT "buck" or plow thru brush,a popular myth. Just because a cartridge offers long range capability,doesn't mean it can't be used at short range-in fact they perform quite well. There yall have MY opinions on just what constitutes the perfect allround whitetail cartridge. Let the battles begin! Neil