Ah.
Can't say I've heard that brought up before, but hey, I'm not the Discovery Channel.
On the face of it I'm not sure that has more effect than gravity, but.. I suppose it's worth a look. At the ranges shoulder-fired weapons are good to, I'm not sure bullet spin imparts much effect at all, other than the well-known stabilizing effect of rifled projectiles... but you have me curious now.
Edit: brief look reminded me of "spin drift", the high and left thing threw me. Yeah, bullets drift to the right a bit. Works out to a couple clicks of windage at 1000yds. I only ever shot out to about 700.