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RCS
08-17-2018, 08:10
Some years I was given a few hundred 163gr US A/P bullets with the black tip, they had been
pulled from cartridges

My question, why do these bullets have a second cannelure ?


44074

Sunray
08-18-2018, 09:12
That's a crimp groove not a cannelure. Most .30 AP was used in aircraft MG's so the crimping was necessary.

RCS
08-18-2018, 06:15
Sunray, it is the second ring or cannelure above the crimping groove - why the second cannelure ?

Tuna
08-19-2018, 09:36
To help hold the penetrator in place within the bullet when it hits a hard target.

togor
08-19-2018, 06:14
Some of the AAPs put them on in WW2, some did not. I have consistently seen those marks on Saint Louis and Frankford Arsenal sourced ammo. Those look like SL to me. The ammo I have from the other AAPs does not show the second cannelure.