It takes more pressure to push a heavier projectile, therefore all else being equal, more kick with a heavier projectile at the same speed. A 150 grain bullet... from any caliber, though there are ballistic coefficients to deal with that I don't understand, will require approximately the same pressure to push the respectively same weight bullet the same speed and the felt recoil will be about the same, regardless of caliber. What makes the felt recoil different is the particular firearm's weight and design and the pressure/weight ratio of the various rounds. For the immense variety of round choices, the 30.06 is hard to beat.
As his first deer rifle, I presented my son with a well used Winchester Model 94 chambered for the .30-30 and equipped with a William receiver sight. He was (is) delighted. I handload, so the first loads he used were assembled with light (110 gr. RN) bullets, but he quickly transitioned to 150 and 170-grain bullets. A Marlin 1894 in .44 Mag is another good choice in dense brush and, if you handload, you can provide him with affordable light loads for plinking and practice. Your son is a fortunate lad. Best wishes to both of you.
Again I want to thank everyone for giving me their in put. After a lot of thought I narrowed it down to a 7MM 08 and a .270 and decided that what ever gun felt best would be the choice between the two. I looked at Browning, Savage, Ruger, Weatherby, Remington and Tikka (Christine said I had too ) The Tikka felt the best and that bolt action is the smoothest I ever felt and since they only had it in .270 that is what I choose for Justin. Here is a picture of the gun it is a Tikka T3 Lite in .270
Awesomeness! I told you they were nice. Look into getting one of these too. http://www.amazon.com/Limbsaver-100...20&sr=8-1&keywords=limbsaver+recoil+pad+tikka
Dude...there isn't any difference between the kick of a .308 and a .270....they kick equally alike, no difference.
Started with a youth model 7mm-08 when I was maybe 9, grandfather bought me a browning A-bolt in 7mm-08 when I was 12-13 and it's still the rifle I hunt with today, (just turned 25) I've killed 7-8 bucks over 200lbs in Saskatchewan with that caliber shooting a couple different 140g rounds. My dad and grandfather who have always shot .270 and or .300 short/ultra mag, have now switched over and we all shoot the 7-08, we've had a couple customs built that weigh about 4.5 lbs with scope without ammunition on savage actions, not a long distance gun but you can it carry like a BB gun all day! When I upgrade it will be the new X-Bolt in 7mm-08 on a synthetic stock, for under $500 I don't know how there can be a better option out there!
I have had a 270, my Dad had a 270, and the kick in factory rounds is stout. For a child, it is to much. The 7-08 and 25-06 are much better. Reloading changes the picture. You can get the load in the sweet spot then.