As far as firearms defense goes it's like this.....
Handgun--------------------Long gun
The gap between these two points is the variability between portability/power/concealment/speed of deployment. All are affected by things like sitting/standing/sleeping bag/activities going on other than shooting/proficiency/legality/politics/optics/safety etc.
Nobody is gonna argue that when they NEED to stop a determined attacker....particularily a much bigger/stronger/purposeful one that likely has the drop on you, is an experienced hunter killer and has the intent and or disregard of taking your life...regardless of if it walks/talks/snorts has thumbs or paws.....would rather have a long gun with sufficient ballistics/capacity/shootability vs something smaller/less competent for the job.
Handguns are for immediate deployment and or fighting to your long gun...whichever comes 1st.
The reality is....the most important part of using a firearm for defense is HAVING one when you need to.
As Canadians our firearm defense is limited to long guns greater than 26in overall unless one is willing to tip the scales of personal protection vs felony criminal prosecution in favor of one's self. A biter pill in the otherwise spectacular free society we enjoy!
Rant over...gettin' to the point..... Wilderness defence is just that...defence and almost assuredly defence when you are focused on the pursuit of happiness and engaged in activity/both hands busy/unaware/distracted...maybe even asleep. The firearm needs to be present, accessable, quick to deploy, snag free, user friendly, familiar (to the point of muscle memory familiar hopefully) sufficient in power and capacity to get the job done...in that order.
If it ain't there fail. If it ain't accessable fail. If it can't be deployed in time fail. If it snags/hangs up/gets stuck fail. If it is too complicated, slow to manipulate, ya don't remember how it works fail. If it doesn't stop the threat and or requires more rds than it has onboard fail.
A shotgun or centrefire rifle of the right ammo config for the bear threat dings the power/capacity bell. Now we get to the size/length/capacity/accessability/deployment/user friendliness options.
Someone previously mentioned actually doing things while packing the weapon...great point. Try going about the activity you will be doing when the bear presents....what size/weight/length weapon are you REALISTICALLY prepared to tolerate carrying/slinging/packing/ the 99.9~100% of the time you won't need it?
The carry method is as or more important than having it at all and it's effectiveness.
Slung/packed/holstered/sheathed/brackets/concealed etc....
ACTUAL REPLY to the posters question goes here: LOL
DOES the 8.5 in give up velocity...yes. Does it give up too much?...if it means the difference between the gun being present or not then NO. If the bear gets you despite being shot YES.
Will a 14/18/20in barrel make a significant difference in this equation?...ABSOLUTELY wrt how portable/carry friendly and ultimately if it's there when needed. NOT LIKELY wrt to terminal ballistics when using it at the distance/scenario of a bear attack.
I am of the strong opinion that the 8.5in pump shotgun goes too far in compactness/portability by giving up capacity/ballistic performance and introducing the possibility of a hand in front of the muzzle when deploying. These are all significant compromises vs a 12.5~14in version that retains a full mag tube, better ballistics, and is safer/user friendly with the muzzle that extra few inchwes ahead of a fully racked slide/hand position..with a buffer if your hand slips forward.
Another issue is the reality of $$. A lot of people need to keep the expense of this device within reason...the 8.5's...decent ones....are double what a similar quality 12.5~14in can be. This affects whether it will be present.
A 12.5in full conventional stocked shotgun dehorned smooth (NO ninja devices protruding from itself) either slung or packed/holstered etc gets as close to the legal size as possible while remaining shootable and has decent capacity to deliver multiple rds (tap rack bang drill/FTF/multiple attackers/FTS etc).
A similarily sized centrefire rifle fits the bill too...although none of them are as capable of being rendered as smooth/snag proof as a 870...hammers are a ##### in sleeping bags!! LOL
Whew....had alotta coffee this am..and always luv a good bear defence thread