OK I thought long on this......
Now that Plissken has his revolver, which he is a deadeye with (Moreso than Riggs is with his beretta), I'd say the gunfight goes down 5/10 for each fighter. What enables Riggs to stalemate Plissken IMO is the rapid fire of the MP5. Yes,Plissken has his silenced MAC10 (I am guessing that was a MAC10), but from what I remember, w edidn't get to see him use it that much. Nor did we get to see Snake use the core burner that much in EFLA. Snake's main strength is quick draw.
H2H........Snake, 7/10. Even though we see Riggs in more H2H battles, you gotta bow down to Snake taking that giant guy in the boxing ring in EFNY.