Haha Warp... I've punished myself by training with a S&W 442 (.38 special) and a S&W 296 (.44 special). Both always leave a lump on my hand, and after prolonged use can cause some bleeding. These days, I've learned to shoot a few cylinders full and leave it at that. Grip positioning and technique can mitigate the risks of shooting with J and L frame revolvers, but it takes some doing.
The Gp100, on the other hand, is wonderful to shoot. However, I perceive 125 grain full-power rounds to have comparable recoil to the 180 grain loads I am using. Both are stout, yet nothing compared to the lightweight guns. Like most things in life, there are trade-offs. The lightweight J frame enhances comfort of carry and ease of concealment. The sacrifice is recoil, sight acquisition, power, and ammo capacity. The Gp100 and 686 are beautiful, highly engineered, and can shoot loads I wouldn't dare to shoot in a lightweight gun. The trade-off is they are a pain in the butt to conceal and are not very comfortable for prolonged carry. Truth be told, I'm on a Remington 870 kick right now for home defense... but I understand its limitations in regards to concealability!
One of the best things about the .357 caliber selections are their versatility. The S&W 686, for example, has several excellent ammunition choices for carry that will match nearly anyone's defense, target, collecting, or hunting needs. Whether it is light and fast, heavy and fast, heavy and slow, hot, cold, warm, or somewhere in between, what matters most is that the shooter has practiced with their ammunition selection to verify accuracy and reliability.
The original poster specifically asked about 125 gold dots, so here is brassfetcher's gelatin video of that round:
http://www.youtube.com/watch?v=Q7w4M-LNXuQ
On a related note, I must say I agree with Don (USSR), whom posted previously:
When dealing with flesh and bone, it's all about penetration and destruction. If a bullet fails to penetrate, it fails, period, and it doesn't matter what the E=1/2mv^2 number is. Just MHO.
This is my personal sentiment as well. Yet, you'll note the Speer Gold Dot in Brassfetcher's video penetrated through the gelatin block.
Hollowpoints, at times, will not penetrate to the vitals. At other times, they will penetrate completely. The benefits of hollowpoint bullet designs, in my opinion, are outweighed by their unpredictability. #Trooper Mark Coates, RIP.
Firearm safety rule #3 is to know your target and what is behind it. If a hollowpoint fails to expand it will likely behave like a full metal jacket...
Hence the benefit of a hot hardcast wadcutter - it is already expanded to full caliber or near it, it will consistently and reliably penetrate the target, and there are no misconceptions about how the bullet might behave.
For more thoughts on bullet selection, see pages 12-14 of this FBI report.
http://www.firearmstactical.com/pdf/fbi-hwfe.pdf
RE: Ammunition Selection Criteria
At the end of the day, I've found that I am most comfortable with hardcast lead for the time being. However, I am not advocating this for everyone. I hike very often, and I make my selection based on that and the other environments that I choose to legally carry in. So that is what I have been training with, and Buffalo Bore has been getting the nod. I have also carried gold dots, dpx, xtp, golden sabres... and a variety of brands that have performed very well for me and for others.
I encourage the original poster to try a few different loads and test them for reliability, accuracy, recoil, style, theoretical behavior, manufacturer loyalty, or any other criteria they set, and I am glad they have chosen The High Road as a venue for learning and discussion regarding our shared interests in firearms.