I'm looking for something in the 158 grain range, with a minimum of 12" penetration, and decent expansion. Most offerings are 125 grains or less.

I plan on carrying Buffalo Bore 158 grain LSWC non-hollowpoint for a hiking round. My chances of needing a handgun are slim, and agressive blackbear encounter even more slim, but I would like the peace of mind. I should just handload a 1000FPS LSWC but I want commercial ammo if I encounter a methhead and defend myself.

For general CCW purposes I have found Hornady Custom 158 Grain XTP, Federal LSWCHP (LuckyGunner tests 21" penetration but minimal expansion), and random Fiocchi. I'd prefer a common OTS ammo but I think I am SOL.

Currently carrying UMC 125 JHP +P because its what I had.

You might want to look at winchester .38 special 158 grain x38spd. It's an old design but it works. It's commonly called the "FBI load".

If I had a .38 special I would probably carry DPX in it http://www.ar15.com/ammo/project/Self_Defense_Ammo_FAQ/DocGKRData/38spl_HorndayFTX_SpeerGDHP_CorbonDPX.htm

The dpx seems pretty consistent and consistency seems to be harder to get in .38 special. it also expands nicely. It is 110gr solid copper but seems to have some of the advantages you would look for with a 158gr bullet regarding consistency.

It was hard for me searching online to find a test for all interesting 158gr loads out of a 4in barrel. There are more tested loads with 2in barrels ... at least it seems so. If anyone has done more testing in a 4in barrel I would also be very interested in the results.

I gave my daughter a box of these for hers.

Just carry your reloads.  I carry handloaded 158gr XTP loaded to about 900fps in my Model 10 Heavy Barrel as my woods carry gun.

If your carrying the lswc for a hiking load , why don't you use the lswc HP for a defense load?

Buffalo Bore has them both. So does Underwood.

If you want a classic load:

FBI load, 158gn LSWCHP. Not sure who makes it now but I'm sure someone does.
Federal Nyclad HP.  Federal does runs of this every so often but it's not always available. Very mild recoiling load.

If you want a more modern load:
XTP, Gold Dot, Gold Dot Short barrel, you name it there's a ton.

Good choice on the outdoors load.

What gun?

S&W 64-5.

The LSWCHPs I've seen don't expand much. I like the SWC, but 900FPS federals penetrate 22" and don't expand

When checking lead HP  for hardness I use my fingernail. If I can dig my nail into it it's soft lead. Should expand  

Underwood  lhp loads are soft   I use them alot.

Buffalo Bore 158gr LSWCHP+P.  Super soft lead with gas check expands GREAT.