A lot of folks say bears are easy to kill, even with small calibers, as long as shot placement is good. BUT....shot placement on a bear is tricky. They look like a black blob, at all angles. Ask a guide, a lot of bears have been shot "behind the shoulder" but are actually hit too far back. Also, the difference between a small bear and a HUGE bear could be 800 pounds. I would rather have enough gun for the biggest bear I could possibly see than have an adequate gun for the smallest.

I am going to Maine for Black Bear next month. I will be using 180 grain 308. I'll let you all know.

Not really. The secret is to come straight up the leg to the lower third of the chest. This shot breaks the shoulder and get the vitals. If the bear isn't broadside the target will be the far shoulder and not the near shoulder but the hold is the same. Bear have smaller lungs than a deer so a shot a couple of inches behind the shoulder will often miss the lungs but if you stick a well made bullet in the shoulder the bear is a goner.

Old saying: "A well hit bear won't go as far as a well hit deer. But a poorly hit bear will go a lot farther than a poorly hit deer." This has been my experience. The number of shots is not as important as where they hit. I've shot a few bears, all with ordinary calibers using ordinary bullets. None of them made it past 30 yds. Shoot a rifle that you know and trust.

I have more than 30 years of experience in guiding and hunting big game in Romania. The best caliber ever for brown bear is 9,3x62 minimum is 230 grains bullets.
To be effective on bear hunting you need a bullet of minimum 220 grains.
Safest kill shot is behind the front leg ( classical double lungs shoot) on the middle of the body height. Not to low, not to high. ( specially in the spring when they have a long hair)

For bear, bullet construction matters more than sheer weight. Your 180gr Accubonds or 200gr Partitions are excellent choices if they shoot accurately in your Tikka. Prioritize a controlled expansion bullet that will penetrate deeply over maximum velocity. A double-lung shot is indeed the preferred aimpoint, just behind the shoulder at the mid-body line. The 300 WSM with proper bullets is more than adequate for black bear.

Your Tikka .300 WSM is an excellent choice for black bear. For bullet selection, the 180gr Accubond is more than adequate if it shoots accurately in your rifle. If you want extra margin, the 200gr Partition is a proven performer. Focus on shot placement over max velocity; a well-constructed bullet in the lungs is decisive. Your aim point analysis is correct – right behind the shoulder for a double-lung shot is ideal. Enjoy your hunt.

Scout hard, watch the wind, carry the right gear, and know your shot. Bears are smart and strong — plan accordingly.

For black bear, the 180gr Partition is an excellent and proven choice. Focus on shot placement over max velocity. A double-lung shot behind the shoulder is ideal. Your wife's 7mm-08 with a good 140-150gr premium bullet is also perfectly adequate with good placement.