JAG came out with their opinion in the '80s that the Sierra was designed for aerodynamic flight, not expansion. To do that, the round was made "backwards" to load the center of gravity where it was needed, and that left the tip open. Likely because swaging it closed accurately over millions of rounds of production was harder and unnecessary. The Sierra design has been used in Olympic shooting since the '50's, too, so it's not like it's been a huge secret.
It's a precision and relatively high cost bullet, tho, and it's not so good in comparison with the steel cored FMJ bullets designed for combat troops. In that scene, you need something that can penetrate. Things like adobe, brick, block, heavy timber construction, sandbags, vehicles, chest harnesses carrying stacks of loaded magazines, and body armor need something tougher to make an effective hit. In that role, you want FMJ, not some easily upset and low penetrating round. In fact, if it goes thru and hits another live target, bonus points!
Most combat casualties are not hit by fire directed at them as the target.
Most combat casualties are not hit by fire directed at them as the target.
That's why the fantasy of the individual marksman being the deciding factor in ground combat and his use of highly precise ammo means nothing. The reality is that a higher number of rounds flying thru the air makes it harder on the opponent. He shoots, moves, and communicates, too, when he's up and running, odds are he runs INTO fire and it may not have been at him at all.
Hence the adoption of the M16 and the worldwide acceptance of the short range full auto assault rifle as standard issue. And why it takes months of basic combat training to improve the odds of survival for new soldiers to raise them to at least 50%.
It's NOT a sunny Saturday afternoon at the range.
No ballistic gel, no wet phone books, no water jugs but the performance on tissue and bone.
