-- r4
.......Ammo Box Warnings........
380, 32acp, and 22mag For Defensive Use
Ballpark energy from common small handguns:
25acp ...... 70 foot-pounds
22lr ........ 100 _ _ _ _ _ 32acp ....... 140
22mag ...... 160 _ _ _ _ _ 380(9x17) .... 190
9x18mak ..... 215 _ _ _ _ _ 38spl ...... 240
9x19 ....... 330 _ _ _ _ _ _ 357 ...... 480
For defensive use under 200 ftlb, I will only use full-jacket or total-jacket
round-nose ammo. The 380 muzzle energy is in the neighborhood of 200 ft-lb,
and that's not enough for some situations. The 380 gets little respect, but
for practical purposes, within 15 yards, it's the right choice for many folks,
as long as the barrel is at least 3" long. (32acp is often enough, if fmj/tmj,
with a 2.7" barrel, since the narrow diameter and taper result in a stable
bullet with adequate penetration.)(Leo needs 320ftlb so hollow points will work;
PDX1 is FBI choice, but make sure it feeds.)
(Avoid reloads and +P ammo in pocket pistols. The design margins are thin, and
often the feed ramp intrudes too far into the chamber, with risk of case burst.)
Since the goal is to damage several inches of soft tissue, or pierce a skull,
or break a leg bone, a full jacket round-nose is more likely to succeed after
passing through common barriers such as leather, bone, or glass.
Powerful 40sw & 10mm hollow points penetrate saturated phone books only 6.5",
without any barrier. www.rathcoombe.net/sci-tech/ballistics/methods.html#handgun
Barriers for a human target might include leather and sternum or rib.
A common attacking animal might be a dog or a rutting deer.
If I'm shooting a 380, I want fmj round nose to be able to get deep into soft tissues with each shot, since many are misses, particularly for short barrels.
Torso penetration past the ribs must be at least 8"; or 12" below the ribs.
There are various test results available for 380 penetration, but none that
I've found are very useful for deciding whether a gun-ammo combination is
enough for self defense where the bullet might pass through a substantial
barrier first. The recent FBI selection testing caused the PDX1 to be chosen.
(One rig on a "Terminal Ballistics" program had denim over a rack of cattle
ribs, followed by several inches of gel, then a heart suspended in the gel.
They tested rifle ammo, and the single layer of ribs introduced uncertainty.)
Even a full-jacket flat-nose has substantially less penetration into soft
poplar wood than the equivalent round-nose full-jacket ammo (the flat nose
becomes concave, even in wet newsprint, and it's known for causing misfeeds).
I use soft poplar for barrier simulation since my test setup must be small,
safe, and cheap; and must have less than 115 dBcs(sound pressure level)
at 3 ft, which is roughly the sound from a suppressed 380.
A 380 is typically rated 153 dBcs, and a 35 dBcs drop is huge; the sound
pressure is reduced roughly 96 percent, and the "perceived loudness" is
reduced roughly 86 percent. [Basic Acoustics, Hall, 1993, p.23]
(The decibel scales are extremely nonlinear; they are exponential values.)
Someday I might use leather over 1/4" plywood over several inches of
oil-clay or microcrytal-wax. But for now, I'm getting a rough idea
of barrier penetration, and comparison of ammo brands and types.
The rig is mainly 2" steel pipe fittings, with branches through reversing lines
and lawnmower mufflers, with the gun firing through a 2" port just 10" from
the test sample. I was able to achieve a sound level of 108-dbcs at 3 ft in the
worst direction, with acceptable blowback from the port.(all in ventilated area)
The test pieces are 2" dia, 5" long, backed by 1.25" pipe cap made to fit
inside 2" pipe, supported by a 1.25" plug, all supported by a 2" pipe cap.
For 32 acp full-jacket(S&B) fired from my Kel-Tec p32(2.7" barrel), typical
penetration was 2.7" with no yaw/keholing (no bulging or cracks in the wood
allowed). This seems adequate, but mainly it's useful in comparisons.
I did the same with 380 fmj(Fed Eagle) from my hated SW380 (3" barrel).
Typical 380 penetration was 3". The low twist helps penetration, but allows
instability. Using my PK(3.66" barrel), penetration is 2.9" (Fed Eagle fmj).
It was a surprise that the PK was less than from the 3" blowback barrel.
It's likely that the PK's aggressive twist rate(9.5") trades penetration
for stability.
There is no yaw/keyholing from the PK indicated in cardboard up to 50ft.
A point-first hit is very important for penetration, particularly if the
bullet arrives at a slanted target surface.
The P-32 penetration was good; but energy is only 148 ft-lb(S&B ammo).
(Fiocchi fair; Geco not available; Buffalo too hot & only in lead.)
This confirms my conclusion that 32 acp fmj from the p-32 is adequate
for common carry, considering size/weight issues, using S&B fmj. It's a
hassle to carry more than a p-32 daily, unless I'm at some special risk.
I will only use fmj when firing 22mag, 32acp, and 380 for defensive use.
Good penetration and expansion is not assured with expanding, possibly
tumbling, bullets.
(I read that Seecamp has a problem with tumble from its very short barrel.)
http://www.speer-ammo.com/products/lawman_cf.aspx
Speer encased bullet, cleaner primer/powder.
.
