[delta13soultaker]

This is just food for thought; not anything meant to say with much certainty what any specific bullet/caliber will do.

I read a post where "winter clothing" was mentioned a few times in regards to choosing caliber size, so I looked into it some.

These examples were from gelatin tests, which are not meant to show exactly what a bullet will do to a live attacker, or even predict what effect a bullet will have on a live attacker, and they do not confirm wounding effectiveness of ammunition. The results do give a close idea of the capability of a specific ammo type to penetrate deep enough (under specific variables) to strike vital organs/halt blood flow when placed well. Note that expansion is important, but directly related to how much penetration occurs. Over expansion may = under penetration, regardless of mass x velocity, vice versa etc etc, so penetration is the focus. Some people dismiss these tests. Some don't. There's 40 ways to skin a bobcat, this is just 1.

Why are these results interesting?
Because a .45 ACP 185gr Silvertip outperformed a .380 90gr XTP on bare gelatin, but on denim covered gelatin the .380 XTP fared much better. ((With the .380 maintaining nearly the same expansion while keeping the same mass.))
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.380 ACP Hornady 90gr XTP JHP
Product Number: 9010, Lot Number: 35ND01 015 Test Date: See Remarks
Test Weapon: Beretta 85, 3.8" bbl

Gelatin Calibration: 10.2cm @ 622 fps Gelatin Calibration: 9.3cm @ 602 fps
Shot # Velocity
Inches Expansion Shot # Velocity
Feet/Sec Penetration Penetration Inches Expansion
Bare Gelatin Denim Covered Gelatin
1 993 12.4 .42 1 1013 14.1 .45
2 1024 10.2 .47 2 1024 12.6 .47
3 1015 11.1 .47 3 1039 14.3 .46
4 1018 11.1 .45 4 1024 13.9 .43
5 998 11.3 .44 5 975 18+ NR
Avg. 1010 11.2 .45 Avg. 1015 See Remarks See Remarks
Corrected 10.9 Corrected N/A
Remarks:
Test date: 9/99.
Gelatin calibration corrected to 9.6cm in accordance with: "Figure 5-2, Velocity Variation Correction to Measured BB Penetration Depth." Bullet Penetration, MacPherson, Duncan, Ballistic Publications, El Segundo, CA, 1994, p. 84.

Five shot average penetration depth corrected to 10.9 inches in accordance with: MacPherson, Duncan: "A Simplified Penetration Depth Correction for Data Taken in Non-standard Gelatin." Wound Ballistics Review 2(2); pp. 41-45, 1995.

Bare gelatin. All bullets fragmented. Average recovered bullet weight: 79.8grs.
Remarks:
Test Date: 10/99.
Gelatin calibration corrected to 9.1cm in accordance with: "Figure 5-2, Velocity Variation Correction to Measured BB Penetration Depth." Bullet Penetration, MacPherson, Duncan, Ballistic Publications, El Segundo, CA, 1994, p. 84.

Denim covered. Five shot average penetration depth and expanded diameter cannot be determined because bullet #5 penetrated entire length of 18 inch gelatin block, exited, and was not recovered. All recovered bullets remained intact.
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Note the .380 expanded to around .45 dia in every firing.
The .45 Silvertips (avg 11.5 inches) and the .380 XTP (avg 11.2 inches) both scored MARGINAL on bare gelatin. The .45 Silvertips scored SATISFACTORY on denim covered; the .380 XTP scored highest with an OPTIMAL rating on denim covered gelatin. So the .380 XTP may have more potential for busting through more vitals under different circumstances than some .45 ACP loads. This becomes important in a fight because perfect shots are not plentiful; things like arms and hands get in the way.

Most of this is not new news to lots of people. If there were a point here it's that (aside from shot placement etc etc) bullet design, not just the size of your caliber, plays a big role in the effectiveness of your weapon.

Why are we so quick to say, "Mines a forty-five"? Depending on what's in your .45, a guy with a .380 could be walking around with more firepower....

My .02

Sources from Tactical Firearms Institute.