Actually, harvesting a bou with a bow is alot easier than a whitetail, just be prepared to hike.
They're not nearly as spooky as a whitetail, just wear good camo and be prepared to hike miles, and then hike some more.
The bou's up in AK were easy to stalk if you're trained on Michigan deer.
I'm sure you are researching everything you can read on these critters...maybe I can tell you some things you may not be able to read anywhere.
Couple tips,
Caribou will walk faster than you can get across the terrain at your quickest pace. If you're gonna ambush'em, pick a spot well ahead of their travel route, and look for funnels.
I know this will sound funny, but we used to hunt the north slope, just north of the Brooks range every August for bou's in the bowhunting only section of the Tundra(5 miles either side of the Dalton) and we used to get the attention of caribou miles away by waving big white flags. I guess it simulated moving caribou and you would be amazed at how many herds we "decoyed" in.
Also, if you're bowhuntin, 40-50yd shots are possible, it's hard to get close when there's no cover. Arrow penetration was nuthin like a moose, and a quick flat trajectory with a 24" in. arrow around 70# worked well.
I don't gun hunt, and talking rifle calibers is like japanese to me, I'm sorry I can't help you there. I used to know some guys up there that would ride their 4 wheelers across the tundra and glass caribou from their bikes. When they spotted a herd, they would ride within range, pull out their rifles and tripods, pick the bulls they wanted, count to three and fire simultaneously. These guys were superb shots and routinely popped bulls at 5 and 600 yds. The racks they scored were tremendous. These guys were serious shots, and serious bou hunters, and they taught me a ton.
If your still hunting through willows, spruce, or other cover, keep your ears peeled. Caribou have tendons between their toes, and when they walk, their hooves snap together and make a clicking sound. One time, as I crouched behind some black spruce waitin on a good bull, I had probably 100 bous walk by at 15 yds....it sounded like a parade of people walking with tap shoes on. Wasn't a decent enough bull in the whole herd though, so I never let an arrow go on that trip, but I heard them coming before I ever saw them.
Another tip is to get good optics. Most people look for bou's too close...you need to reach out with your optics and try to spot herds 4 and 5 miles out. Up there you should be able to see forever, and the bou's will look like ants on the tundra. If the ground cover is thick enough to hide a bedded bou, try to spot antlers sticking out of the brush, alot of times this will be all you can see.
My final tip is this: Most young bulls look ALOT like cows, they all have antlers. Unlike a whitetail, the ***** sheath of a bull caribou is quite obvious under the belly of a bull. Too many caribou are passed up, or misidentified and wrongly shot because hunters have a hard time identifying sex. If it's a bull, it WILL have an evident sheath....locate that part of the anatomy before you shoot.
Hope some of this junk helps ya out!
Let us know when you are leaving, so we can wish you luck!!
Huntnut