[lepton]

Assuming that it was an AK-47 actually being discussed here. $600 would be an incredible deal.

[Farmer Dean]

Local dealer has them for 679.00 new.600 would seem about right for a good used one.I actually bought a new one in 2014 for 629.00 plus tax.

[angryoldfatman]

I had heard it was an SKS, which actually makes $600 sensible, even overpriced.

It turns out I was wrong. According to a gun-enthusiast site, it was a Saiga AK-74.

http://www.ammoland.com/2016/07/rifle-used-dallas-ambush-common-sks-not-assault-rifle-assault-weapon/#axzz4EF15QE2n