The Incredible Shrinking FBI Round

[Tamara]

You know, the ironic thing is that my original post had little, if anything, to do with the Miami firefight. It was about bullets. Eighteen words out of several hundred made an oblique reference to the shootout.

Four pages of gum-flapping about Miami (which folks, including me, have a truly ghoulish fascination with) later...

[krept]

It started out about contraction and ended up about the main theorized reason for initial expansion.

[OBdoc]

Tamara:

i agree with you. It has always been counterintuitive for me to believe
that a 'faster' projectile to be somehow inferior to a 'slower' projectile
given the same bullet weight and same type of bullet.
I have come to understand from hunting experience
that penetration is very important. If penetration were not so important,
and if the advocates of 'high velocity & low mass' were correct,
then we would shoot dangerous african game with light fast bullets.

Interesting and throwing more of a muddle on the topic in my mind,
is a very interesting essay at the Garrett ammo
company site http://www.garrettcartridges.com/44mag.asp which
addresses some of the physics which seems to be counter to my
previous opinion about bullet speed...

Since wound channel diameter is much more a product of meplat diameter than actual bullet diameter, it is our view that all non-expanding hunting bullets should utilize very broad meplats. Broader meplats result in larger diameter wound channels, which increase the speed of incapacitation. Another benefit of broad meplated bullets is increased penetration depth. This relationship of penetration depth to meplat diameter is quite interesting, and fundamental to proper full-potential bullet design. It is commonly believed that bullets with less meplat diameter, such as truncated cones, offer less resistance to penetration and, therefore, provide deeper penetration. This would be true if terminal stability was not influenced by meplat diameter. However, bullets such as truncated cones with less frontal area, and greater front to back weight disparity, are far less stable upon impact, and, as a consequence, provide less penetration. It is always easier to observe than explain, but clearly as the weight disparity between the front of the bullet and the rear of the bullet increases, there is a tendency for the heavier end to overtake the lighter end upon impact. This takes the form of the rear of the bullet moving forward faster than the front, resulting in yaw which greatly inhibits penetration. Simply stated, the bullet goes sideways. However, when the weight disparity between the front of the bullet and the rear of the bullet is minor, or non-existent, this tendency to yaw is greatly reduced and the bullet penetrates deeper. However, once the issue of front to back weight disparity is corrected, and bullet yaw is substantially eliminated, further increases in meplat diameter result in reduced penetration depth. These facts have led to our choice of .320-inch diameter meplats for our 44 Magnum Hammerheads. Significantly less meplat diameter results in reduced penetration, as does significantly increased meplat diameters.

Bullet hardness is an important factor in bullet strength, but if not properly managed can cause bullets to fracture when their inherent strength is exceeded. Common to machine cast commercial cast bullets is the use of high antimony alloy. This is used as it provides an acceptable rejection rate, as utilized in automatic casting machines. Unfortunately, however, high antimony alloys tend to fracture when stressed beyond their inherent strength, as in point blank impact into the toughest game. I find this to be unacceptable for bullets that might be used against heavy or dangerous game...Our SuperHardCast 44 Magnum Hammerheads are the result of an unusually comprehensive approach to ammo building. By designing our own super efficient weight-forward bullets, we are able to achieve more power per unit of chamber pressure than can be achieved using conventional designs. Our weight-forward Hammerheads are also target-accurate, delivering 1-inch groups at 50-yards from accurate revolvers. Also, our .320-inch meplats offer the best in wound channel diameter, penetration, and quick anchoring of game. Finally, our special alloy, bullet hardening, and careful hand-casting provides completely reliable performance against the heaviest game, where bullet impact stresses are the greatest. Our 44 Magnum Hammerhead Ammo is simply without peer in the realm of big game 44 Magnum hunting loads.

[hjwilner]

I met an agent a couple of years ago that still carries a 3" model 13, loaded with whatever 357 mag ammo is approved (125 Gr, I think)...

His idea, no thought involved, point & shoot....


I guess that works for me..

[Fred Hansen]

:d