Teeder,
Here's an excerpt from the chapter in Gun Gack II about "Killing Power":
"Eventually it occurred to me the diameter of .338 bullets is only 3/100th of an inch larger than .308 bullets, which ain’t much. After experimenting a little with a Starrett digital micrometer, I found that wrapping a .30 caliber bullet in a single layer of stiff business card resulted in a diameter of just about .338 inch.
It also occurred to me that an expanding bullet’s initial diameter isn’t what kills big game. Instead it’s the 'mushroomed' diameter, which punches a much larger hole. So I opened the over-sized tackle box containing my collection of recovered bullets from half a century of big game hunting, and took out all the .30s and .33s.
The bullets included a pretty comprehensive list: Barnes TSX; Hornady Interlock and Interbond; Norma Oryx; Federal Deep Shok; Nosler AccuBond, Ballistic Tip, E-Tip and Partition; Speer Hot-Cor; Swift A-Frame, and Winchester Fail Safe. I measured the width of each bullet’s mushroom at its widest point, then measured the next-greatest width, averaging the two measurements.
Since there’s only .03 inch difference in unexpanded .30 and .33 bullets, I didn’t expect the average difference in expanded bullets to be much larger, and it wasn’t, turning out to be just about exactly .05 inch. But the .30s averaged larger, not the .33s!
This seemed odd, so I looked closer at the results and discovered the reason: Two kinds of .30 caliber bullets expanded very widely, Hornady Interbonds and Norma Oryxes, all averaging over .7 inch across their mushrooms, while none of the others measured over .668.
None of the .33s were Interbonds or Oryxes, so I eliminated those two bullets from the .30 caliber results, then re-averaged the rest. However, this still came out slightly in favor of the .30s, .631 to .620. Obviously, results might be slightly different for other batches of recovered .30 and .33 caliber bullets, but my results indicate there’s no major difference in their expanded mushrooms."
Can also post a later portion of the chapter, about why I (along with some other experienced hunters) think calibers (not cartridges) larger than .338 up tend to kill quicker.
