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Para Bellum · February 23, 2009, 03:42 PM

.223 with M193 ammo from a barrel with at least 20".

Excellent round against non-armoured thin opponents like homo sapiens or the like.

When the M16 was first used in Vietnam, it was assumed that the smaller 5.56mm round would make much smaller wounds than the 7.62mm M80 round fired from the M14. Everyone was surprised to learn that M16 wounds were often much more severe. In order to explain this discrepancy, it was theorized that the slow 1:14 barrel twist made the bullet less stable in flesh and caused it to tumble, resulting in the large wounds. In fact, the slow twist only made the bullet less stable in air. Any pointed, lead core bullet has the center of gravity aft of the center of the projectile and will, after a certain distance of penetration, rotate (yaw) 180° and continue base-first. This is where the appearance of "tumbling" came from.

The actual cause of the larger-than-expected wounds was not a result of this yawing of the bullet, but of the velocity of the bullet coupled with the bullet's construction. M193 bullets have a groove or knurl around the middle, called a cannelure. This allows the mouth of the case to be crimped on to the bullet, preventing the bullet from being pushed back into the case during handling and feeding. The cannelure also weakens the integrity of the bullet jacket.

When the bullet struck flesh at a high-enough velocity, the bullet's thin jacket, weakened by the cannelure, could not survive the pressure of moving sideways through the dense flesh. Instead, the bullet would only rotate about 90°, at which point the stresses were too much for the bullet jacket and the bullet would fragment. The results were a wound that was far out of proportion to the size of the bullet. Yet, the twist rate of the barrel and therefore the rotation speed of the bullet, is not a factor in the fragmenting equation.

If the velocity is high enough this breaking up is pretty dramatic and causes equally dramatic wounds. This is because the fragments travel rapidly through the temporarily crushed tissue and tear it. Most tissue is very elastic and will stretch quite far before returning to its normal shape (this is called the temporary crush cavity) but the addition of quickly moving fragments makes permanent the cavity that might otherwise have returned after the impact and therefore creates a much larger wound.

With the right speed (20" barrel) the M193 yaws on impact and breaks apart at the cannelure, fragmenting into the target. Extreme damage:

Or 100 grain Black Hills in calibrated ballistic gelatin. Note the amazingly short neck before
tumbling (1 inch) and the dramatic fragmentation along with almost 13" of penetration:

This is very good and extensive info on the subject:
http://razoreye.net/mirror/ammo-orac...cle_Mirror.htm

and: http://le.atk.com/pdf/223RifleDataBook.pdf

Given the extreme terminal performance (if barrel lenght & bullet fit together), the light recoil and high number of great platforms (AR-15, Mini-14, AUG, FAMAS etc, Rem 7615p ...) my choice would be a .223.

February 23, 2009, 03:42 PM	#17
Para Bellum Senior Member Join Date: January 7, 2005 Location: right there Posts: 1,882	.223 with M193 or 100 grain Black Hills .223 with M193 ammo from a barrel with at least 20". Excellent round against non-armoured thin opponents like homo sapiens or the like. When the M16 was first used in Vietnam, it was assumed that the smaller 5.56mm round would make much smaller wounds than the 7.62mm M80 round fired from the M14. Everyone was surprised to learn that M16 wounds were often much more severe. In order to explain this discrepancy, it was theorized that the slow 1:14 barrel twist made the bullet less stable in flesh and caused it to tumble, resulting in the large wounds. In fact, the slow twist only made the bullet less stable in air. Any pointed, lead core bullet has the center of gravity aft of the center of the projectile and will, after a certain distance of penetration, rotate (yaw) 180° and continue base-first. This is where the appearance of "tumbling" came from. The actual cause of the larger-than-expected wounds was not a result of this yawing of the bullet, but of the velocity of the bullet coupled with the bullet's construction. M193 bullets have a groove or knurl around the middle, called a cannelure. This allows the mouth of the case to be crimped on to the bullet, preventing the bullet from being pushed back into the case during handling and feeding. The cannelure also weakens the integrity of the bullet jacket. When the bullet struck flesh at a high-enough velocity, the bullet's thin jacket, weakened by the cannelure, could not survive the pressure of moving sideways through the dense flesh. Instead, the bullet would only rotate about 90°, at which point the stresses were too much for the bullet jacket and the bullet would fragment. The results were a wound that was far out of proportion to the size of the bullet. Yet, the twist rate of the barrel and therefore the rotation speed of the bullet, is not a factor in the fragmenting equation. If the velocity is high enough this breaking up is pretty dramatic and causes equally dramatic wounds. This is because the fragments travel rapidly through the temporarily crushed tissue and tear it. Most tissue is very elastic and will stretch quite far before returning to its normal shape (this is called the temporary crush cavity) but the addition of quickly moving fragments makes permanent the cavity that might otherwise have returned after the impact and therefore creates a much larger wound. With the right speed (20" barrel) the M193 yaws on impact and breaks apart at the cannelure, fragmenting into the target. Extreme damage: Or 100 grain Black Hills in calibrated ballistic gelatin. Note the amazingly short neck before tumbling (1 inch) and the dramatic fragmentation along with almost 13" of penetration: This is very good and extensive info on the subject: http://razoreye.net/mirror/ammo-orac...cle_Mirror.htm and: http://le.atk.com/pdf/223RifleDataBook.pdf Given the extreme terminal performance (if barrel lenght & bullet fit together), the light recoil and high number of great platforms (AR-15, Mini-14, AUG, FAMAS etc, Rem 7615p ...) my choice would be a .223. __________________ Si vis pacem - para bellum If you want peace - prepare for war Last edited by Para Bellum; February 23, 2009 at 03:50 PM.