Bullet failures. Fifty years ago, I had some too stoutly constructed 150 grain ..270 Bronze Points fail to open and just punched holes in a lung shot deer, despite three being in a softball size group. A fourth shot to the spine in front of the shoulder ended that. Little meat damage.
The only Texas heart shot I ever made was with a .30-06 loaded with 180 interlocks, about twenty years ago. Perfect shot, no entry wound, blew up the pelvis and the bullet, requiring a neck shot to finish him off. BTW, meat damage was minimal. I did a horn display of that escaping mule deer's rack. He tasted good too.
To the .243, I had a Sierra 100 SPBT come apart on a deer shoulder many years ago. A fragment found it's way into the spinal cord. I went to the 100 NP and have never found a reason to change. I use 70 Sierras for coyote and other pests.
It has been my experience that at some time or another, lots of the older bullets failed to perform to expectations. Newer technology has given us a much better product, and it is not limited to any one brand. These days, if the proper bullet is selected, the caliber seems to be on steroids compared to early in my hunting life.
Jack
Interesting to hear you say that. I had a similar experience with early 150 grain .30 caliber Bronze points in a .30-06. When I recovered the deer, it looked like he had been shot with FMJ's. I switched to C&C's and have never looked back. About 20 years ago, I was telling the story to a young guy, and he looked at me like I was insane. It seems that his experience with Bronze points was exactly the opposite. I guess that some time between our experiences, Remington changed the jacket.
I haven't shot many deer with my farm beater .243, but those I have shot were shoulder shots (I have neither the time nor inclination to chase deer) with 100 grain Sierra Pro Hunters. Penetration has been very good with drt's the result.
