Ah, the old "nature vs. nurture" discussion. While an argument could be made that the material properties of the barrel (material from which it's made, method of rifling (CHF, etc...), and/or material treatment (melonite, etc...)) play a role, it seems that a bigger role is played by the manner in which the barrel is used (big powder charge with a (relatively) small bore, high rate of fire, etc...).
By and large, an argument could be made that "speed kills"; this can be applied to both projectile velocity and rate of fire.