[twntaipan]

What type of rifle...

Any medium caliber rifle round

What type of weapon would the al-Qaeda boys have practiced with in Afganistan? AK-47? Does that qualify as a medium caliber rifle round?

[GOPyouth]

What type of rifle...

A Red Ryder B.B. Gun with a compass in the stock, and this thing which tells time.
I know this isn't a laughing matter, but it's late, and I need a laugh.

[infowarrior]

The AK-47 is chambered for a 7.62mm x 54mm round which definitely falls under that category. However, the AK is an assault rifle designed for high firepower, and not the kind of accuracy seen here. This is not to say that the shhoter isn't using something like a Dragunov sniper rifle, which is chambered for the same ammunition...

the infowarrior

[Brad C.]

The thing is the shooter(s) could be using any old standard hunting rifle and scope set available at any gun shop or swap meet across the US.

The thing that stands out to me is the "1 shot, 1 kill" method, indicating that the shooter has some experience with this type of thing. It is one thing for somebody to flip out and start shooting everyone around them, indicating that the person lost control of himself or the situation. It is something altogether different to have a series of killings at different locations and times, indicating that the shooter is very much in control of the situation.

[FreedomPoster]

What type of weapon would the al-Qaeda boys have practiced with in Afganistan?

The only ones with any accuracy that are commonly in the SovBloc arsenal are the Moisin Nagant and the SVD. But it wouldn't take a good marksman long to train up with any commonly available U.S. hunting rifle.