4700 fps (1,400 m/s) is beyond the typical 20-30mm APDS launch velocity. 1,300 m/s is a  more "typical" velocity. 

Barrel wear with APDS rounds is generally less than with conventional rounds. Discarding-sabot projectiles are lighter and the barrels see less time with the projectiles 'inbore''. The projectiles usually have plastic rotating bands and bore-riding surfaces; reducing frictional and engraving forces. Initial propellant gas temperatures may be higher, but total propellant energy down the tube is about the same - pretty simple thermodynamics when specifications dictate a maximum pressure. 

Very high rate of fire without spreading it out over multiple barrels isn't common with 20-30 mm weapons and might require some active cooling. 

.338 caliber might be problematic beyond its thermodynamics. High rate of fire means high temperatures. 4,700 fps would require an awfully light projectile and/or high pressures. The unit cost of ammunition with such light projectiles (read as poor flight and terminal ballistics)  kind of works against the idea. .50 caliber attempts have not worked well on a cost/benefit basis.