Mad Scientist, I don't think GI Joe had a 20-lb sniper rifle in mind.
GI Joe, you would be surprised by how pleasant it is to shoot and carry a well-balanced hunting rifle chambered for a large "African" cartridge.
I too am a rather slim-built guy, own several rifles (try 50+!) and have wanted to dabble with large calibers: the "bug" bit me after reading John "Pondoro" Taylor's African Rifles and Cartridges.
My first experience was a Ruger #1 in .416Rigby. The fact that I absolutely loved it is evidenced by my handle here on TFL. However, I soon found out that killing Texas whitetails with it was a bit "much", and that rifle is now sitting pretty much unutilized in my closet.
But my infection for large "African" rounds remained. So, I equipped myself with a .375H&H, and I noticed that the recoil, trajectory and meat damage it inflicts is not that different from a run-of-the-mill 300 Win or 7 Mag. What's different is how very dead it kills and how much it penetrates.
With a factory 270-grain load, you can duplicate exactly the trajectory of a 180-grainer from a 30-06. With handloads you can beat that. But what energy it imparts to the game when it hits! Try and see if you don't believe me!
Now, let's go back to recoil. If your 375 weighs around 9lbs "fully dressed", you will not suffer from gun-headache or a sore shoulder. I'll stake my reputation on this right now, here on TFL! The .375 H&H is an old cartridge, a far cry from the modern Weatherbys or (worse) the Rem Ultra Mags. It was intended for low pressures, and it does not use that much powder.
Let me tell you two stories. One involves a .375, the other a 30-06.
In the first instance, I was sighting in one of my .375H&H for a Montana hunt (whitetail, mulie and perhaps elk); I fired around 35 rounds from the bench and never even started flinching. I did not use a syssy bag or any other "cushioning", yet I did not develop any type of bruise. The inherent accuracy of the 375 soon satisfied me that the rifle was zeroed. On the field, I killed three nice animals without ever noticing the recoil. The meat from one of them (a nice, juicy doe) is still in my freezer, as prime and blood-free as I have ever seen. And, as food for thought, consider that in the case of this doe we never saw the entry-hole until we totally dissected the carcass!
In the second instance, I had to sight in a batch of .30-06 rifles for a group hunt. They were lighter rifles, weighing only about 7lbs. The day after, a pale hue of purple was distinctly showing on my right shoulder. A day later, a California pig fell to my 30-06. The 165-grainer had taken out both lungs, the top of the heart, and a rib. While breaking the rib, the shot created secondary fragments that literally shattered the meat all around. My backstraps were necessarily shorter and the meat was kind of bloody - I ended up chucking it.
Moral: the more I shoot and hunt, the more I love the .375H&H and am convinced that it is one of the best candidates for best all-around North American caliber.
Life takes me all around the country, and game can be very diverse - from a distant pronghorn to a close moose (and every possible variation on the deer theme in between). If a .375H&H is in my hands, I feel confident - ALWAYS. Period.
Am I alone or crazy in thinking that? Than so is one of the most respected hunters and writers of our time, one gentleman by the name of Craig Boddington. I rest my case.