None of these bullets ever expanded on the birds. Used wing shots on all. Got lots of feathers and probably dead birds, but couldn't find them. Also used a 400 gr. lead .45-70. He got away.
I think why the 260 gr. HP .454 works is the HP with the velocity of the round creates enough tissue shock to disrupt the spinal column. Exits and internal damage are 1- 1 1/2".
Got a Swift 265 gr. HP (BIG cavity as compared to Speer) mixed up in my loads and used it once. Massive damage, 20% of breast gone, 2 1/2" exit. This is NOT a turkey bullet, but is great on deer.
Oh, the .357 shot was 5 yards!! Called him right in and was camoed good. 158 gr. Sierra JHC. Bye,bye, birdie!