Thats what Madmarco said when I bought it. Luckily I have a ton of 7.62X54R in all configurations. No heavy ball in this baby!
I researched a little more and found that if it is a PSL it will have a triangle with an arrow in it under the receiver. Those are rare if it is and they also sometimes have the third access hole which the BATF considers a machine gun receiver even if its welded shut.
Heres a link for some great info on these beauties. http://www.dragunov.net/romanian_psl.htm