158 SWC with gas checks velocity

I have with 160 grain SWC plain base. Thru a 6"barrel. 1 head, 2 heart lung. Both under 40 yds.
Close enough for either a head shot or to for sure, heart shot.
The heart lung shot I have done twice. Will not "drop" a deer in spot. But will provide a good humane kill. As long as you leave it alone for a bit, then track it. Get the adrenaline going and it becomes way less humane. Plus it taints the meat.
As I found out on my second 357 heart lung kill. Better to let them go lay down, bleed out. Then go track them.
 
If you want to use the 358429 I can't think of a single reason not to. No matter how fast you push it compared to the 358156 it's going to penetrate more. I would expect through and through at anything above 900fps or so. Of course I'd almost expect the same from the 156 at close range.
 
I have 2 pretty accurate 50 yards loads with cast bullets. According to the Lyman manual they should be 900 to 1000 fps. 6 inch barrel. Is this enough for 40 to 50 yards deer hunting. The hotter loads are less accurate. Thanks johnny
How much less accurate?