Actually guys, WW2 ammunition marking is different from current practices. Here is what I have gathered from various references both online and in books: Black tip - observing (small puff of smoke on impact), Green tip - armor piercing, Blue tip - incendiary, White tip - tracer (short range) and Red tip - tracer (long range).
In addition to the color of the annulus there was often a letter on the head stamp... for example W for AP, O for observing, G for tracer, B for incendiary, etc. The main thing is that standard ball ammo had a purple annulus so if it is any other color then do some research before messing with it.
Hope this helps.
Safety note: Marking practices varied somewhat during the war. For example, at one point armor piercing was indicated by green annulus (color around the primer cap) only. Same goes for some incendiary, observing and tracer rounds. Hence, it is important to use caution when using WW2 vintage ammunition as you might be shooting something you don't intend. I have heard stories of guys using inertia bullet pullers to deactivate surplus ammo and the puller blew up as they thought the bullet was a standard ball round when in fact it was an observing round or incendiary!
Here is a website I found that explains it all: http://enfieldking.tripod.com/enfieldking/id12.html
Last edited by Infanteer on Sun Oct 24, 2010 2:17 pm; edited 2 times in total