A Rottweiler is a big, tough dog. If he ran off and dropped in 30 feet, that's not bad ammo performance. It's when he ignores the hit and starts chewing on your leg is when you should re-think your ammo choice.
The only published ammo street performance data is the work of Marshall and Sanow. It's a bit dated (2001) but still gives good guidelines. Listed is the .357 load followed by the % of one-shot-stops:
Federal 125 gr. JHP 96%
Remington 125 gr. JHP 96%
Speer/CCI 125 gr. JHP 93%
Federal 110 gr. JHP 89%
Remington 110 gr. JHP 89%
Winchester 125 gr. JHP 87%
Federal 158 gr. Hydra-Shok 87%
Winchester 145 gr. Silvertip 87%
Federal 158 gr. Nyclad HP 83%
Remington 125 gr. JHP (Med. Vel.) 83%
Remington 158 gr. JHP 82%
Winchester 158 gr. LSWC 79%
You will note that the lighter, high-velocity bullets have been the best stoppers (on people,) with the heavy bullets not doing as well.
All things being equal, such as bullet expansion characteristics, a heavier bullet will penetrate more deeply. Whether your 15 gr. heavier bullet would significantly do so is highly debatable. Go with one of the several 158 gr. .357 loads if you want substantially greater penetration.
Whether your 140 gr. Sierra JHP at 1300 ft/s would give you a couple of inches more penetration with plenty of expansion, nobody can say for sure. You, or somebody, would have to test the two loads against each other in ballistic gelatin under controlled conditions. (Which is by no means a quick, easy and inexpensive task.)
The only published ammo street performance data is the work of Marshall and Sanow. It's a bit dated (2001) but still gives good guidelines. Listed is the .357 load followed by the % of one-shot-stops:
Federal 125 gr. JHP 96%
Remington 125 gr. JHP 96%
Speer/CCI 125 gr. JHP 93%
Federal 110 gr. JHP 89%
Remington 110 gr. JHP 89%
Winchester 125 gr. JHP 87%
Federal 158 gr. Hydra-Shok 87%
Winchester 145 gr. Silvertip 87%
Federal 158 gr. Nyclad HP 83%
Remington 125 gr. JHP (Med. Vel.) 83%
Remington 158 gr. JHP 82%
Winchester 158 gr. LSWC 79%
You will note that the lighter, high-velocity bullets have been the best stoppers (on people,) with the heavy bullets not doing as well.