Shooting a 500-600 lb bear with a 140-150 gr bullet is putting yourself at unnecessary risk. Yeah, guys shoot em with bows too. But if they're not in a tree stand, they're nuts. Wait a minute! This guy is coming up here to hunt bears. So he probably will be "hunting" them in a tree stand with a bucket of bait out front (very thrilling). Go ahead then. Shoot em with a .22 if you want. But I'm staying up in the stand while you walk around by yourself in the thick Ontario undergrowth trying to find the bear you hit with a marginal gun.

With a heavier bonded or solid(barnes type) bullet i think you're fine. The heaviest Blackie i've seen was shot in Pa. with a .30/30 at 300 yds. While larger diameter than the .270, (.308" vs .277") we all know the .30/30 lacks velocity and terminal(kinetic) energy at that range. The bear however was not swayed by this. The 600# bruin barely fit in a pick-up bed. The .30/30 is a very popular bear cartridge especially amongst old timers and northeastern hunters. The .270 with a good bullet would be much more effective, seems to me anyway.

A bruin was hit by a semitruck about 65 miles north of my home (NW Ontario) a few years back. It tipped the scales at about 760 lbs. An 800 lb blackie was reportedly shot near Dryden. I personally saw one at the dump in Armstrong that MUST have easily gone over 600 lbs. I've seen dead ones at 550 and this guy dwarfed those. Regular size bears are hard enough to kill. Sorry, but I wouldn't feel very confident looking down the sights at one of the new generation black bears with a .270.

Use the .270 and 150 grain premium bullet like the Swift A-frame or a Barnes X bullet. Enjoy your hunt.

Crap. You're right. I can dream, can't I? Bear Claw for bear. But yeah the TBBC 140 grain is where it's at if you're trying to go big with a .270. I think it's a better idea than a 150 with lesser bullets. That 140 grain A-frame fits too.

A lot of people think the big bullet makes up for things, but a faster better bullet will perform more effectively. OK well a 150 grain .277 TSX is like a freaking javelin and probably can't be beat, but at this point you just need to gun up. If you're needing 150 grain or larger bullets, take a rifle meant to shoot them.

I'd use mine on one. Shot placement is more important than gun size.

I know a guy who killed his first black bear with a 270 i beleive he was hunting in Manitoba (SP?) the shot was close it was under 50 yards.

Honestly I think the best factory round here would be Remington with 140 grain TBBC.

I have to say that if you're wondering, worrying, and agonizing whether the round is powerful enough to be SURE, it isn't.

I would think about bears as if my life depended on it, and with them, it might be.

A 270 WSM will definitely do the job but be prepared to make at least one follow up shot. I killed a 760 lb black bear in Hyde County NC last November with a 270 WSM and posted the pic somewhere on this website. He was 156 yards away. The first shot hit him right behind the shoulder and would have killed him but he just stood there. I kept firing until he rolled and stopped moving. It took six rounds to drop him where he stood. If you are going to shoot at bruins that large, a semiauto is good. I used a Benelli R1.

To add to my last answer...

I think ammo is a little tougher to locate except at actual sporting good stores. You may not find it in every gas station and hardware you walk into. Something to consider if you're an hour from home and have forgotten your bullets.

A 270 will be fine for black bear. Go with a heavy bullet.

ur just fine dude. it will take it down just fine. you will have fun shooting them too. im going there to some friends and i hopefully can fill a black bear tag while im up there. have fun!

@claycooper: he's not going to be enjoying his hunt if he's dead. go big.