Not as a bear-specific hunting rifle, but as a general purpose cabin carbine, I wouldn't think that .300 blk being fired semi-auto out of a 20 or 30 rd. mag wouldn't make short work of that grizzly.
It has "similar" ballistics to a .30-30 and the amount of shots you could put in quickly makes alot of sense.
The bear defense question is wrought with guys talking about the quick handling of a lever action and how Griz can cover 40 yards just about as fast as you can recognize he is coming.
Who thinks it's a good choice and what specific .300 blk ammo should be carried?

Shooting anything,  with enough of anything,  will kill it eventually.  The difference is how long it takes to die, and how bad it can fuck you up in that time period.  I'd re - think that.

I don't think you can use such a (caliber) compared to a grizzly the same reasoning as having a 9mm 8 round pistol vs. 15 round pistol for human self defense.

I'd rather have a short double barrel shotgun with slugs or 00 buckshot. In other words something powerful enough to stop it in it's tracks.

Love the 300BLK but it is not for Grizzly's.

There isn't much that would fit in an AR platform that I would take out to Grizzly country. Even some of the bigger rounds like the 458 Socom would worry me against a Grizzly. A slug from a 3 inch shell would be the way to go with a Grizzly. Remember at 600 pounds they can take a lot of damage with their big bones and muscle before going down so you need something large to get the best results.

If I was making an AR-pistol bear gun it would be a 9” .458 SOCOM

I'd want something that would penetrate and crush bones better if bears were any concern. Against humans it would be cool.

I'd probably use a .458 socom AR as someone already said.

A non-expanding 12ga slug would be nice

It’d probably do in a pinch if stoked with 110 grain Barnes TTSX super sonic loads. Would not be ideal of course for grizzly bears, but excels at general cabin use of which duty would be common.

Defensive costal grizzle predatory attack would be a rare encounter. Unless you live where this is going to be a real concern like on a river in Alaska it is probably not worth carrying a dedicated firearm for it.

$150.00  3" chambered 12 gauge pump with Brenneke Black Magic Magnum (12 GA 3") Slugs.  Forget the 300 Blackout for Grizzly Bears, would it kill one, yes, but why take a chance.

Not even close to a 30-30, don't know where you get this.

Maybe because the BO with light bullets has around the same vel as a 170 30-30 bullet.

Anyone would take the 30-30 loaded with 170gr bullets against a griz over a BO. Look up some chart ballistics. I'd rather have the lever gun in 45-70 but you laid down the rules.

This and throw the BO at the bear to distract him while you dump him.

Leave the blk at home. Think, for a moment. The 300 is basically a shortened 5.56. Take that info and load a bullet that takes up a good amount of case space- no fuckin' way. If you shoot him with that- and he finds out about it- you're gonna be the big chunks in bear shit.

You don't know much about ballistics do you?

I mean, I’d use it if it’s what I had on me, but it’s certainly not something I’d pick for the task. I’d want about as much thump as I could, I’d be at the upper limits of an AR-15 frame, 7.62X39 at minimum, but something probably closer to 50 Beowulf, .450, .458 etc. I’d probably feel better with a large frame 30 cal though loaded with fusions or the like, or a shotgun loaded with slugs.

It’s not so much a question of whether a round can/will kill it. Lots of them can do that, eventually. It’s more a question of which round will kill/incapacitate it before it closes that gap, and they can close a gap pretty fast. Anything that can dump lots of firepower quickly and with precision would be nice. There’s a lot of right answers to that, but I’d pack as much caliber as you can accurately place several shots within the span of a couple seconds.

Lol

same as a 30-30. Not even close.

I used my 458 when I was in AK.

Griz needs big bullets to get through the hide/bones.

I was replying to the OP. Not you.

Certainly not the ideal Grizz gun or load but with properly loaded ammo, it should work. Heavy 170 or heavier hunting bullets loaded hot. I have wondered what velocity the 300 could push a 180-200gr .308 hunting bullet. We know it's good for subs, but what about pushing a typical subsonic load super. Could we get 1500fps out of a 180 or 200gr bullet? The bullet would not expand or perform like it would out of a 308 but should give plenty of penetration.

I bet it would beat the 10MM loads and many people feel a good, heavy, full power 10MM would be enough.

Personally, I would look at maybe a .308 AR pistol with a 12" barrel loaded with proper 180gr loads. (or my Benelli M1 loaded with slugs)

Sure a 308 would better. That isn't what he asked, he asked about a choice between the 2. And now your going for a 308, Ok I'll grab a 12 gauge slug gun.
Then we can just drop this. if the dude can't figure it out let him go with his gopher gun.

So by his options! A 300BO or a lever action 30-30, the choice is plain to anyone with a half a brain which gun to grab.

The BO is a powder puff gun. I can get 130gr speers going close to 2700 in my marlin 30-30 if you want to compare light for caliber bullets in the same gun.
The BO will do the 130's@ 2000 fps if your lucky. They have no powder space for fast loads with heavy bullets, what you got is a pistol AR, that's it.

The BO isn't going to come close to that or any other bullet if you went up in weight. Hornady's 160gr with case full of Leverevolution powder will do 2350fps I 30-30

Yes you can beat Hornadys loads. What is the BO going to do with that bullet 1300 fps 1400 maybe. Pistol loads have more ft lbs of energy. I'd have 170gr Nosler
partitions loaded with Leverevolution given his choices. I wouldn't be to worried going out and about either.

Your 30-30 is truly the powder puff gun compared to my XXX.

There are plenty of guns that shoot much faster and harder than either the 300BLK or the 30-30. Which doesn't make either of them powder puffs.

What can be said is that neither of them are good choices for a gun in Grizzly territory.

There are advantages to both guns as in the lower weights the 300BLK gets close to the same power as the 30-30 and as the distances increase the better bullets and their Cd that come with the 300BLK tend to narrow the power gap even more. Some of the other advantages of the 300BLK is it doesn't need a lever to cycle, can be loaded to 30 rounds, is made from the most common brass on the planet, followed with the third most common bullet, it has expandable subsonic bullets, it uses the most common platform in the U.S. which can take any optic and suppressor with ease, it can be loaded with an additional 30 rounds in a matter of seconds without having to drop or insert each individual round into a tube and it can be made safe without cycling all the ammo in the magazine through the action.

The 300BLK also excels with short barrels something the 30-30 doesn't.

There is much respect for the longevity of the 30-30 but it seems you don't like the 300BLK. Funny thing is I wouldn't worry as I don't think many people cross shop lever action guns with Semi auto AR's or bolt action. So there is no reason to be so defensive of your lovely 30-30 by berating the 300BLK.

Wake me up when your fuckin sermon is over.  Did I hit a nerve preacher?  OP is the one who made the choice, You take your gopher gun and I'll take the 30-30. Never once did I say either one was ideal for Griz, read much? Home schooled? I said I'd take a 12 gauge slug more than once, or a heavy 45-70.

I believe the OP was simply asking if the 300 would work. Not asking if it's equal to 30-30 or 12GA. As the OP noted, having 20 or 30 rounds on tap, fired semiauto, will have a quality of it's own and may make up for the anemic 300 loading.

With proper bullets, I believe it would work. I'm also arguing that the 300 can be loaded with heavy bullets and be superior to the 10MM handgun.

Just seen this, so ah you're saying the BO has the same power as a 30-30 with lightweight bullets?

Not even in the same ballpark junior, like I said 2700 for the 30-30 with 130grs and maybe 2000 with the BO so please stop this nonsense dreamer.

Better shape bullets you say, ok how about the 140gr Hornady flex tip at 2600fps, and your BO chugging them out at 1800-1900 fps. Which one is better?

When you study the ballistics chart as you need too, maybe a light will come on? You have no clue. Like I said OP rules between 2 calibers and guns. see!

I bet you see lots of Alaskan guides carrying AR's in your little dreams. I'd tell you they carry heavy lever action's, but I can't keep on explaining everything to you.

Lets go with this, at least you realize the BO is anemic. Better than carrying a toothpick or a 22 rifle.

But OP did ask about the 30-30 in comparison, saying it was equal to the BO. A 125 gr bullet going 2100 fps does not equal a 170 bullet going the same speed.

Or even worse a 160 flex tip going 2300 fps. So lets bury this anyway.

Your 10mm vs BO might be close, if 44mag or 454 not even.

Your reading comprehension is about as good as your manners.

No where did I say that it was the same power. Just like the 458 socom has a ton more power than your 30-30 with much faster follow up shots, quicker reloads, more rounds and the capability to take on any optic or muzzle brake without modification. Which would make your 30-30 a very wimpy and beyond anemic in comparison. To the point it shouldn't even be considered a carry gun unless you had nothing else.

Because all you can see is power when I listed about 15 things that make the 300BLK a much better carry or defensive rifle than the 30-30. I mean when was the last time you saw any soldier or police man carrying a lever action rifle? The 30-30 is almost completely unsuitable for most defense situations (maybe for some cattle rustlers in the old West) is definitely unsuitable for offense situations and is relegated to hunting non dangerous game such as deer. Which is can do pretty well but once again there are a lot more people out there hunting deer with 300BLK than there are with 30-30 so please lay off the hate.

Also I have pistols that carry more energy than your powder puff wimpy 30-30. Power is all relative, Here are a half dozen guns that fit in an AR frame that make your 30-30 look like a pop gun: 50 beowolf, 458 Socom, 6.5 Grendel, 450 bushmaster, 375 Socom and .500 S&W magnum. They all are much better in just about every aspect when it comes to shooting other than nostalgia. Yes the last one is a pistol round that with only 6 inches of barrel blows away your precious 30-30 when it comes to power. What is sad is that you are putting down the 300BLK because it isn't as powerful as your 30-30 yet so many other guns are much more powerful than your 30-30.

As for the power difference between the 30-30 and the 300BLK. Inside of 200 yards whatever either hits wouldn't know the difference between the two. They are both capable of taking game at those ranges and anyone with half a brain wouldn't touch the 30-30 other than having fun with grandpa in the back yard plinking or hunting some non dangerous game.

GD does not disappoint! Fellas, this is a place for discussion. Conversation, to get varying points of view on a topic we all love. Whoever gets their butts hurt in here can go cuddle with their 3" .12 gauges and their belt fed .45-70's. It's just a question about .300 blk, which I actually am brand new to. To those who contribute real info, thanks. We don't have alot of Griz in Colorado (DOW says none, but theyre seen from time to time). I do have a couple .30-30's, a couple shotguns, etc. This topic is because the .300 blk is a helluva lot of fun and might just be sitting next to me at the campfire this year. It's nothing personal to you ballistics fellas.

If you are going to be sitting by the fire with that rifle just make sure your Will and insurance are up to date for your loved ones. No caliber butthurt, just good advice.

If I was building a bear defense AR, it would be 458socom.

When it comes to bears, hard hitting, heavy projectiles are desirable.  .300bo could work, sure.....but I want to have something that can immobilize them, not just bleed them.  Heavy, hard hitting rounds will do that much better....especially since we aren't talking about a long range shot where you have time to let the bear get out of it's rage-fit after being hit.

I have and love the 300 blackout.

Using a 300 blackout for grizzly is like using a picture hanging hammer to drive framing nails, it can be done but you will have to hit it a lot more.

Nevermind

Say there zippy, you still can't follow the OP question, are you really that stupid? It's between the mouse gun and the 30-30. Are you hurt? Have sad feeling's.

Now your talking about cops & Military? lol Where are you going with this, It's between the mouser and a 30-30. you act like I got one gun boy LOL

I have more than 20 rifles and a dozen handguns one is a 454. I do love my 30-30's, have 2 of em. Your taking this in all direction's like a hurt little school boy LOL

Psst, I also have a couple of AR's zipp, did you know a 5.56 rd fired from an AR has more energy than your mouse gun at 200yds? You really are the gift that keeps on giving LOL

30-30 beats your mouser at all range's, remember that's the 2 guns we are talking about. Question for you, can you just try to keep it on topic?
30-30 also has more energy @ 100yds than either the socom or the beowolf by 250ft lbs. Don't fret you dragged them into this, not me junior. keep up.

Try with all your might to remember the OP post- a grizzly, OP's gun in hand- a BO mouser, and he like you don't understand ballistics, thought the mouser had the power of a 30-30, with me so far? So OP asked if mouser was good gun to have in griz country, still with me so far junior? I told him he was wrong about the
mouse gun having same power as 30-30, still there or did I lose you again, I know it's a lot to absorb, but try, your making yourself look like an idiot.

Here, repeat very slow one word at a time- 300 BO VS 30-30, ok pumpkin. LOL This should be the end, right turbo?

I hope 737 outta the sky don't see your post, he be all over you with military, Police,  and nothing to do about nothing in all direction's. The little fella is butthurt bad.

I'd just get a 308 AR, you want power then get it. LOL

Maybe coming from you 737 can understand, so far no luck from me.

Same here, I'm done! >>>>>>>>>>

Finally something everyone agrees on.

We understand how bad you feel that the 300BLK is better in every way except power. It is close enough though that anything shot with either gun will go down just the same. I don't understand why you are so butt hurt that the 300BLK was compared with the 30-30 as it really isn't that far apart in performance especially when you take into account the further you go out with the bullets the better the 300BLK becomes compared to your 30-30.

Also can your 30-30 do expanding subsonics which is a major factor in the 300BLK? that would be no. Can the 30-30 be loaded into a 30 round magazine? That would also be no. Can your 30-30 be put into one of the most common shooting platforms on the planet (I'll give you hint to what platform that is since we are on a website named after it)? No can't do that either. What about quick reloads? Nope still can't do that. In other words the 30-30 while being a fun round to shoot out of a platform that was state of the art in 1860 it meets almost none of the requirements for self defense or what people are looking for today. But you keep plugging away gramps hoping that by knocking the 300BLK someone will want a 30-30 instead since so many people cross shop those two rifles.

Relish in your nostalgia while putting other cartridges down because the 300BLK is continuing to gain popularity while the 30-30 will soon be a foot note in the evolution of the gun.

From line made by the great Curly Bill in Tombstone "Well...Bye"

Not a hunting thread. CoC 6.