Bear country Insurance

[targshooter]

I'd like to see a .375 , .416 or .45-70 semi-auto for hunting or use as a companion rifle in bear infested areas. This would enable a good shot to get multiple hits on target in a charge situation, an ability that could save the shooter's life. Are none of the present auto-loaders durable enough for such a cartridge? The 350 Remington as a basis for a cartridge using a 300 grain .375 or a 400 grain .416 would be good bear insurance, as would the .45-70 in a semi-auto. I would think the gun manufacturers could find a decent market for such a firearm. Any thoughts from any other backwoods adventurers?

[Siskiyou]

I assume you are talking about large bear other then Black Bear?

At one time the Browning BAR came in the .338 Winchester Mag.  I suspect that rapid aimed fire from the Browning BAR would be very effective.  I am not from the spray and pray school of thought.  As I recall in that little war in the 60's, early 70's even the Marine's tooks 20,000 rounds to kill an enemy.  But in many cases the military used spary and pray tactics.  

Siskiyou

[targshooter]

Hi recoilpad and Siskiyou;
Yes, I was thinking of those individuals who must contemplate being chewed on by the big bears. I was unaware that the AR-15 large bores were so powerful. I am not a fan of the M-16/AR-15 firearms, but as this is not a combat situation and the firearm will be used only in situations where it can be maintained properly, I am curious. Are the uppers  expensive? Any other gunsmithing work needed other than to remove the old upper and drop this baby in? Are there any problems getting or reloading ammo? How have the firearms held up after extended use? Any such data available? Interesting, any additional information?  
Regards