My fault for not explaining better.
There is not much point in comparing penetration of an animal to penetration rates in regular ballistic gel. In real life #7.5 shot doesn't pentrate 6" of meat. If it did they wouldn't have needed to use BB and #2 shot on geese for the last 100 years.
Regular ballistic gel is good for discovering the comparitive toughness of a bullet but not much use for relating to real world performance on killing game animals. My ballistic testing mixture is from a recipe I came across years ago and I didn't learn it on youtube. In my gel a winchester super-x power point 30-06 180 gr will penetrate approximately 12"-14". A 30-06 180 gr solid will pentrate 20-22". If you have some experience shooting game animals then you would know that compares favourably to results that would be expected in bullet performance on MEAT. And 3/8" spruce plywood is not a bad substitute for hide and hair on a large animal but that does depend somewhat on the animal.
Yaw was not a factor in the 41LC testing but bullet shape certainly was. In lthe lower velocity bullets that we are discussing, a flat nose will penetrate several inches less than a round nose. OTOH Flat point cast bullets create a larger wound channel than RN cast bullets.
I have slaughtered dozens of cattle and I did it all with a brain shot with a .22 solid. My father would have tanned my butt for experimenting with chest shots on beef cattle. It wasn't done.
If that anaemic little bullet had hit a rib square instead of just touching it, then would we expect that 300 ft lbs would have been enough energy to make a clean kill or would the bullet have spent itself breaking the rib and stopped short? At best it's highly questionable. I don't criticize it because i don't know the circumstances but it's not something I'd brag about.
You probably had good penetration on your cow because you were in soft organ tissue. Proof again that shot placement is still the single most important factor in killing anything. I don't think you'd experience that much penetration if you were shooting through solid flesh and muscle.
Some more random data for comparison.
38spl 150 gr RN: 7"
38spl 158gr SWC: 5.5"
.455webley 265 gr RNHB 6"
41 LC 205gr RNHB 6"
41LC 185 gr FNHB 4.5"
41LC 215gr heeled RN 200 gr 7"
..22LR RN 7"
.22LR HP 3.5"
.223 55gr FMJ 10" (tumbled 3 shots out of 4)
9mm Para 147gr FMJ 11"
44spl 250 RN 9"