"Weight retention" is a means to an end.
That being full penetration.
It is not the goal but the means to a goal, and that is often forgotten.
There are situations where a bullet breaking up to a large degree is a desirable trait.
Examples can be;
Shooting game in neighborhoods, or areas where many buildings are the norm.
Shooting fur-bearers and not wanting an exit.
Shooting bad guys in a house or in crowded cities.
Shooting varmints where ricochets are to be avoided.
Weight retention for general big game hunting is seldom a bad thing, but if you have a bullet that always gives you an exit and still sheds 60% of it's weight, retaining more weight does nothing more for you. Exits are the goal!
So if your rifle and load goes clear through, the rest of the details are largely unimportant and irrelevant.
I remember a man trying to tell me that a Swift A-Frame was a better bullet for hunting elk in his 375H&H then my Nosler Partition was in my 375H&H, because the Nosler "only" retained 75% of it's weight and his Swift retained 95% of it's weight. But I pointed out the mission was to expand and then exit the elk, not impress it with mathematical formulas. So my 375 with my load gives me exits 100% of the time, at any range I have shot, and at all angles I have shot, and NO elk I have shot has gone more then 20 feet with almost all of them falling instantly or within a body length. So............how could another bullet be "better" then that on elk? I am batting 100%. You can't get better then 100%. In fact my old favorite bullet (can be bough anymore) was the Winchester 270 grain Power Point and it was a cup/core bullet, but I never retained one in any animal I ever shot and they killed like lightning.
Is the A-Frame better for Cape Buffalo? Probably.
So what? We were in Idaho Montana and Wyoming. Not Botswana. Once you have a hole as big around as your bore diameter could make and it goes clear through, no amount of power in tow as it hits the ground behind the elk would make any different.............would it?
I believe the bullets that hold together are more reliable killers as a rule. 50+ years of experience using all kinds of bullets have brought me to that conclusion.
Bullets that break up often kill like an electric shock, until they don't! If you have that happen 10% of the time it can be said that you may have to kill 10-15 with the same load before you see such poor performance a few times, or even one time. So many hunters will stand on a track record of 6-8 kills and think they have the information down pat. Such is not always true. That's where having 50+ years of killing game and seeing game killed in several states and in 5 countries has been valuable to me.
The times they don't work well usually are the result of the bullet breaking up in a way that it either (A.) doesn't penetrate deep enough or (B.) it turns off course radically and doesn't go through at the angle you want it to.
Bullets that ball up and hold together often kill instantly too, but some times they give a slower "shock effect" on game, but again, standing on 50+ years of experience, I will say a good fairly straight hole that goes clear through is always fatal to the animal and those hit with such bullets usually do not go very far at all. Some are hit too far back and the bullets only get one lung or maybe even just the liver, but those animals sill bleed out fast and are easy to follow. Not so with bullets that don't exit.
Just 2 weeks ago I saw an exception. One that is in opposition to the above rule, but it is also the only one I have ever seen that was so opposed to that rule that it surprised me this much . It was a 250 grain 9.3MM Accu-Bond fried from my 9.3X57 Mauser that hit a white tail buck as perfectly as you could hope for, and the exit was the size and shape of a chicken egg dead center in the chest on the off side,yet the deer ran over 200 yards.
So there are always exception to the "rules" but the odds favor the bullets that mushroom, don't blow up, and exit.
I have seen many dozens of game animals run very long distances and have had to track them down many times. Most long tracking jobs I have done for clients were the result of less then perfect marksmanship, but many were also the result of bullets that come apart and don't exit. I have seen the same thing ONCE with a bullet that preformed the way I like,........ that being the 9.3MM I just mentioned above.
I am 62 years old now, have been hunting big game since I was 8 and guiding since I was 14. ONE time I have seen a good hit with a bullet that held up the way I'd prefer go farther then about 70 yard. My best guess as to how many times I have dealt with the same kind of long trails (many times much longer)from game hit with bullet that break up would probably be 50-60 times.
But to recap my 1st point, if a bullet comes apart and still goes clear through in a fairly straight line it doesn't matter if it comes apart (other then spoiling some meat)
As for me I have to stand with the odds because there is no such a thing as a 100% certainty in hunting.
I still use bullets that are "unknowns" to me but because I have the luxury of killing 5-14 head of game every year, I can afford to try some bullets that I have no "track-record" with. I like to know, as opposed to just guessing. I do note however, in most cases when I do that, I keep the magazine loaded with bullets I know will work, so if I need a 2nd shot I have one quickly. So far this year I, my Wife and my friends I have hunted with have killed 4 deer, 12 antelope and we still have 2 more deer to get and 4 elk.
In a nut-shell my description of kills with bullets that hold together enough to always exit is about as follows;
40% "bang-flops.
30% Bang,-Run hard for 3 seconds then stagger for 2 seconds and fall.
30% Bang - stagger for 3-5 seconds and fall.
My description of kills with bullets that break up and don't exit, or those that turn off course 30 degrees of more inside the animal is as follows:
70% Bang-flops.
20% Bang- run hard for 10 to 30 seconds and fall.
10% Bang Run hard for 30 seconds to 5 minutes and lay down.
Shots from both types of bullets can and do result in some game running, but in those cases, the ones that run without an exit are A LOT harder to track (much less of a blood trail) and those that have been shot with bullets that break up, if they run, usually will run much longer distances than those that do have exits.
That is why I have concluded that the rounds that give exits are more reliable killers overall, Not always faster killers, but only 1 in 54 years shot with a bullet that held together and left a good exit was hard to find. 50-60 others that were hard to find, some that ran almost a mile, were the ones shot with bullets that break up. (disregarding gut shot or flesh-wounded game regardless of what they were hit with of course)
