My friends and I made some target stands last time we went out shooting... we made it out of wood and steel hinges... the hinges were leftover steel beams from a construction site that were cut up into smaller pieces, probably like 10" x 10" with a hinge overhang so we could attach it to the wood.
ANYWAY, we brought a bunch of rifles... including some 5.56 rifles, as well as an L1-A1, and an M1A (308)... The steel was about a half inch thick, so we didnt think the rounds would penetrate.
When we were done shooting and wanted to disassemble our rig, we decided to shoot the steel plate with the AR-15 using AP rounds that were supposed to be "the shit". So we shoot it with a single round from about 50 yards, we here the "PING" of the metal, and know we hit it... so we walk down range to see what happened to the steel... Armor piercing my ASS! Made a little dent into the steel just a little bigger than the standard 5.56 rounds.
So we bust out the M1A and fire a single shot at the metal... walk up range and look to see what it did with a standard FMJ round... went through that steel like hot butter! Frigging AMAZING! I couldn't believe how much more punch the .308 round had over the AP 5.56! It was uncanny.
Needless to say, we used the L1-A1 and the M1-A to destory the target as the 5.56 rounds wouldn't do the job.
And thats my semi-unrelated story.