I thought i had my improved choke in my 500 Mossberg.
I think i changed them out for squirrel hunting last year.
I shot a few rifled slugs through the mod. choke tube. They were win. super x one ounce rifled slugs.

Shotgun season starts Saturday. Could this have hurt my gun or the mod. choke or is it OK.

Also if i use the improve choke tube for slugs for deer i take it i need to go back out a pattern the gun with the improve tube

You can shoot the rifled slugs through a full choke without hurting it. Its designed to be able to deform and the lead will smush out and the lands will fill in thegrooves of the slug before it hurts a barrel or choke. Yourchoke is fine.

http://www.huntingnet.com/forum/tm.aspx?m=3157779
Heres a thread already about this...

Not a problem.

You didn't hurt a thing. Foster type "rifled" slugs were designed to be safely fired thru any choke except perhaps the ultra,super full choke tubes.

thanks guys the guy at the local pro shop told me the same thing