According to the Bureau of Alcohol, Tobacco, Firearms and Explosives, shows that just over two million AR 15 rifles were produced for domestic use in the United States from 2000 to 2010. Taking these numbers into account, it can be estimated that approximately 200,000 have been sold per year.

The serial number and possibly on the bolt.

325 people killed by rifles in 2012

He did.

The NORINCO CQ5.56.

DPMS doesn't make an AR-15 - AR-15 is a copyright of Colt Firearms, and thus, only they and companies licensed by them to manufacture the rifle can actually call it an AR-15.

As for their AR-pattern rifles, they typically come with a 5.56x45mm chamber, which is also capable of handling the .223 Remington.

CMMG's "bargain bin" rifles.

The typical AR15 fires the same type of bullet as the M16: a .223 caliber (5.56mmx45mm NATO) round.

There are AR-15 rifles that have special barrels made for a variety of popular cartridges, even the little .22LR.

Depends on make and exact model, but prices have increased GREATLY in the past 2 weeks due to a spike in demand- currently about $1500 and up.

In the ounces range.

By the true definition, only one with a selective fire option (full auto or bust fire) would be. By the politicized definition, it would be if it has two or more of the cosmetic features outlined by the BATFE in 1989.

Take your pick... BCM, Daniels Defense, Yankee Hill... pretty much any name with a repute for quality will make a product which meets and exceeds your durability requirements. I tried looking, and I haven't really found anything which tested quad rail systems to the breaking point, but you really can't go wrong with anything from a quality manufacturer.

Yes they make one.

They can be a little more forgiving of less frequent maintenance, but the leading cause of jams with AR pattern rifles is actually from the cheaply made mil-spec magazines, not the action. Also, with a piston system, carrier tilt becomes an issue of concern... they do make carriers and buffers designed to resist carrier tilt, though.

The average shooter probably won't actually gain anything from a gas piston AR vs. a direct impingement rifle, whereas, say, a Navy SEAL would, as they wouldn't be required to open the action and drain out the system after it was submerged before firing it.

Variant of the AR-15 manufactured by Colt. It had a 'slab side' lower and no forward assist.

The M3 is the semi-automatic version of the Ar-15 (M4).