you think so?..i dont know, i think since we are talking single band (even if its a 20mm) it would be unlikely to cause the sort of shaft whip to justify an enclosed track, and with a 6.5 spear the friction could absorb much of the spear's energy...i would tend to think either 6.5 or 7mm spear on a regular track, im just trying to figure out the difference between railgun and open track in the options above, if somebody could help that would be cool
