I know the Topic is Mossberg 500, but I was confirming what Gandilamont stated.

This is from Mossberg


Mossberg

Can I fire slugs through my 835® vent rib, Accu-Mag® choke tube barrel? No, 835 field barrels (those with a ventilated rib) are "overbored", the extra inside diameter may cause the projectile to "wobble" producing unreliable accuracy. A projectile may wedge inside the barrel causing an obstruction. Obstructions of any kind can cause damage to the firearm resulting in personal injury. Dedicated smoothbore or fully rifled slug barrels are available for the Model 835®. Other 835® Accu-Mag® Choke Tube notes: Buckshot and steel-shot loads are not recommended for use with an Extra Full Turkey tube installed.