Effectiveness of flat-point bullets?

[481]

Weird. The Winchesters FPs had the lowest velocity but greatest penetration. How'd that happen?

Yet I thought the FPs did shake up the gel block more. Am I imagining that?

Flat point bullets penetrate farther because they produce a larger stagnation front that causes radial displacement of the test medium away from the sides of the bullet (also known as super-cavitation) that reduces frictional drag (which arises from contact with the sides of the bullet) leaving only inertial drag components in place and allowing the bullet to travel in a near vaccum. Round nose bullets, having what amounts to a very small meplat, if one exists at all, tend to upset and tumble, or yaw, since no pressure front exists to stabilize the bullet against steering forces (that is, frictional drag) that act along the curved surface of the rounded nose.



This effect results in greater stability (straighter tracking through the target) and deeper penetration due to elimination of frictional drag forces.

 

[sequins]

Thanks for all the informative posts everyone. I carry factory loaded gold dots in my glock, same as local LEO in my area, per the advice of Mr. Ayoob but I always greatly enjoy learning about the performance characteristics of my options.

 

[brewer12345]

I used a big (198 grain) cast bullet with a .19" meplat in 30-06 cruising along at 1900 FPS or so out of the muzzle to take a doe last fall. This was moving faster than a handgun bullet, but I think the principal is similar. The bullet was not hardcast, maybe 12 BHN. The slug went right through the doe in a quartering shot and did not hit any major bones (went through a rib on exit). There was expansion since the exit hole was about half an inch in diameter. The bullet was very effective, but:

- At 9X it wasn't very difficult to make a good shot at 80 yards. Wasn't much heart left and both lungs had damage.
- A lot of energy was not dumped into the doe. The bullet pretty much made a straight line through the boiler room, do not pass go, do not collect $200.

Is a 150 pound mulie doe similar to a person? Probably close enough for government work. A sizable meplat would do some good damage, but it probably comes with more penetration than might be desirable and in a semi auto feeding might be an issue. At typical handgun speeds, a big meplat probably won't give expansion unless it is extremely soft.