A topic that seems to fascinate many of gun enthusiasts what gun is suitable for defense against four legged predators such as any of the big cats or great Bears.Traditional wisdom usually recommends a long gun such as a 12 Gauge loaded with heavy slugs or perhaps a Rifle chambered in .300 Win Mag or greater.Handguns choice recommendations usually start at .44 Mag go up from there.These are good choices for many circumstances,but remember the goal is defense rather than Hunting & the two must be distinguished.A Hunter's goal is ideally to take the animal with one clean kill shot although a follow up or two as well as a finishing shot is common compare that with defense where you are not stalking your prey,but rather they bring the fight to you and is often sudden and unexpected.If you are a hiker or camper,then a long gun such as a rifle is simply too heavy and burdensome to carry and in the defense realm can often be to slow to bring into play as you will likely be carry it with a sling slung over your shoulder.In such circumstances a sidearm at the hip is much more accessible and likely to be brought into action fast enough to be effective.The revolver is often recommended because they are chambered for more powerful cartridges than autoloaders and if you are fighting at muzzle contact distances,they can pressed against the flesh and fired whereas a autoloader with foul the slide and jam in such circumstances.
Grizzly Bears move extremely fast for such a large animal and can run up to 35 mph.Cougars and other big cats can spring on from an ambush position along a hiking or jogging trail in the blink of an eye.With the quickness and unexpected attack potential by these animals in such that they can be on top of you in split second,the argument for the revolver being able to be fired more effectively from a close quarter position seems valid.Why do so many of these same advocates then recommend a log gun for Predator defense?If there simply is so little time that the fight will invariably end up in contact range with the beast on top of you,then how possibly would you be able to bring a long gun into play? For that reason I say the long gun is a relatively poor choice for realistic defense against a surprise large predator attack.
I'm a big advocate for hammerless snubnose revolver for close quarter grappling situations as they are the hardest gun to disarm from their rightful owner and will fire at contact distances as well as being able to actually be fired from a jacket pocket with jamming.They make great choices for CCW for Civilians and back up guns,but their limited capacity and indifferent accuracy at distance make then a poor choice as a primary arm for Military or Police who must voluntarily engage offensively with large numbers of enemy personnel and often at a distance.That's very different than Civilian self-defense,just as Hunting a Large Predator differs from simply Defending against just as Humans attackers differ from Animal attackers.For example....If a Human Being is attacking/mugging/raping you & you draw a gun on them,they will invariably try to disarm you of that weapon.In contrast a animal will make no such attempt since they have no clue what a gun is or what it does,so in that respect,the advantages of the revolver may be somewhat mitigated or at least diminished somewhat. It is often sighted that every stat about Bear attacks demonstrate that the attack happens unexpectedly at those aforementioned muzzle contact distances.Of course they do since otherwise if contact were not made,there would simply be no attack.You never hear about the times when a Bear attacked or approached and was shot or otherwise scared off since most people are only concerned about the sensationalism of a real Bear mauling.
So,down to specific recommendations.I don't feel a long gun is real practical or even a necessity,but if I was to personally carry one, I would likely choose a short lightweight pumpaction12 Gauge stoked with slugs although a 00 Buckshot to the face of a Bear would likely do the trick.I wouldn't want a Rifle.A Bolt Action is to slow for follow ups, a lever action I find awkward. A pump action Rem Rifle in .30-06 or .308 might be OK or even a semi-auto in 7.62 x 51 NATO/.308 Winchester might be acceptable.I wouldn't want a rifle,but that's what I'd pick if I had to pick and remember that we're talking Defense against all comers,NOT Hunting.
In handguns,a Glock 20 in 10mm is certainly a viable choice.It holds 15 rounds standard and 20 with the Arredondo mag extensions.There is also a 6" Factory barrel that will help the 10mm round reach it's full potential.Some will argue that the 10mm is too light for the great Bears,but I don't personally feel that way.The Denmark/Greenland Special Forces carry G20's specially for Polar Bear Defense.Shot placement is extremely critical against large predators. Just about anything could be considered marginal in terms of stopping power against large Bears,so just like against 2 legged predators,you have to do your part in the sense you must stay calm and make accurate hits.There have countless examples of Grizzlies taking multiple hits from 12 Gauges as well as Magnum Rifles and .44 Magnums.It is therefore imperative that you have to make your shot counts.The Glock will be lighter to carry,carry more rounds,be quicker to get the shots off & control and follow up with than any large Revolver Caliber Hand Cannon.The Head & Face should be your target getting off as many accurate shots as you can.Ammunition choices are some of the heavier & hotter offerings from Cor-Bon,Double Tap & Buffalo Boar.The frequently recommended suggestion of shooting the Bear in the shoulder to halt the Bears forward progress and "roll him"seems misguided & unrealistic in my opinion.The Glock 20 is very versatile covering a wide range of possible encounters whether the threat has two of four legs and even makes a decent hunting handgun.Close quarter/Contact distance shooting is it's greatest liability.
A .44 Magnum in a modest Barrel length would also be a good choice.The Nightguard 329 in .44 mag or the 329 PD are both lightweight guns to carry,but are a beast to shoot,but we're talking defense not Hunting or Target practice.The all Stainless Steel 629 with say a 4" Barrel is a common recommendation albeit heavy for long trips and it only holds 6 rounds. A .357 Mag can often get the job done,but 6-8 rounds at best and it's performance doesn't match up with the 10mm.A light .357 Magnum(such as 340 M&P) in the pocket as a backup though would be a very good idea and doesn't add much weight at all..44 Mag is only a consideration if dealing with the large Bears or very large Cats.357 Mag is just fine for Cougars or Mountain Lions and probably Black Bears although 10mm is better and the most versatile.If your set on a Revolver, I would recommend the .357 Magnum over the .44 Magnum if the .44 is really too much for you to control and you are able to get follow up shots off much faster and more accurately with the .357. Or you might choose to carry two guns having the best of both worlds available depending on how much weight you can or are willing to carry.
Awareness will probably be your greatest defense,so pay attention to your surrounding when in Bear or Big Cat country.And remember that movement is you friend to create the proper angle & distance to get the shots off you need.
Besides a suitable handgun,I'd also carry a large canister of Bear/Pepper Spray that would likely be effective against Big cats as well and would be my first line of defense although I'd also have my sidearm already drawn and at the ready.
If your heading into Bear or Big Cat country,do a lot of research and by no means take what I've written down here as some guarantee to keep you safe because there is no such thing when it comes to large predator defense.