Alright, spent a while doing some testing for my own benefit. I was attempting to answer 3 questions, but the results could actually help answer several others.
1) How much of a penalty would a person pay, performance wise, running a reduced load in a .44 Mag, i.e., can a lower velocity load still perform like a higher velocity load with a high SD bullet?
2) How much performance can be had from a more packable gun, like a 10mm, in comparison to a .44 Mag?
3) How much difference is there between standard FMJ and hotter loads in the 10mm?
To answer this I shot spruce, otherwise known as AK ballistic gellatin...
Here is the general gist.
.44Mag w/ 300g WFNHCGC @ 1340 penetrated about 13" of spruce.
.44Mag w/ 300g WFNHCGC @ 1010 penetrated about 6 1/2" of spruce.
10mm w/ 200g HCSWC @ 1000 penetrated about 6 1/2" of spruce.
10mm w 180g FMJ @ 1000 penetrated 4 1/2" of spruce.
There were several different rounds, but it ended up being 4 180s, 4 200s, and 4 300s (2 each of 2 speeds), so chrono speeds aren't great averages, just ballpark.
***My thoughts*** IMO, this shows that if you aren't carrying full tilt+ 44 loads with heavy hardcast, you aren't accomplishing anything particularly special with it. If you choose to download the round for followup shots, it may be acceptable to carry another platform without any major performance penalty. I am not particularly concerned with frontal area of the bullet on a brown bear, because a killing shot isn't going to be one that makes it bleed out, so the .029 larger hole shouldn't be particularly significant.
The 200g load has a smaller meplat, which could make some difference in penetration. It was the only one I had, and I figure it makes a best case scenario as long as it doesn't tumble, which it didn't. That being said, I'm not expecting a huge drop in penetration with a slightly larger meplat.
With the significant difference between the 1000 and 1340 FPS penetration on the .44, it makes me think that the Buffalo Bore 220g 10mm, which clocks over 1100 FPS, could easily show penetration 75-80% of the hot loaded .44. Also note, I believe that the 1340 .44 load is over book max, so is there for comparison more so than to show what a .44 is capable of. That being the case, the gap between the hottest Buffalo Bore 10mm and .44 in penetration may not be that large.
So what are your thoughts on the info as presented?