Let me ask you fellers : if I remove the choke thats screwed on to the muzzle of my SA-20 Mossberg Turkey Thug , would it then be a cylinder choke and would I then be able to shoot slugs thru it ?
NEVER shoot ANYTHING out of a barrel with choke threads with no choke installed. Doing so will damage the bare threads and probably affect accuracy.
I picked up a skeet choke for The Thug. Was $12 inc. S/H off Gunbroker. They usually run $15-$20. I did this to "save" the vented turkey choke that came with it for when and if I ever use it to hunt turkey. Skeet is one size smaller in dia. than cylinder. Turkey is the tightest there is and not suitable for slugs or steel shot. I think you can go down to IC or Mod. with slugs no problem but you shouldn't go tighter than that.
The SA-20 takes Benelli/Beretta "Mobil" chokes by the way but NOT the "Crio" style... PS: and make sure you are ordering/buying 20ga chokes and not 12ga...