I have been reading posts in other forums swearing that rifled slugs are not intended for rilfed barrels due to lead deposits left in the rifled barreled due to the rifled slugs.  They went on further to say rifled slugs are intended for smoothbores, and foster style slugs and all other smoothbore slugs were intended for rifled barrels.  If all this is true it is news to me, someone please chime in if ya know.

bmc,
 
What you heard elsewhere is what I have been lead to believe also...
The rifled slug through a smoothbore causes itself to twist with barrel friction. If you have grooves on the slug, & the barrel is rifled, it can cause exessive leading, & can affect accuracy due to the rifleling not  getting a clean cut on the slug.
 
A smooth slug would be the thing to shoot in a rifled shotgun barrel.
 
Correct me if I'm wrong guys...
 
Rockinbbar

First off I should say that I have no experience shooting shotguns with slugs. With that said this is the way I think it works. Rifled barrels are for saboted slugs. The foster and Bernieke(sp?) slugs are for smoothbores. The fosters are undersized and are best used if you have any choke in the barrel you are using. The rifled Bernieke slugs are for smoothbore slug barrels without any choke.
 
The saboted slugs are stabilized and achieve accuracy by being twisted like a rifle bullet.  But both of the smoothbore style slugs don't spin.  Their stability and accuracy comes from their weight forward design.  The hollow base in the case of the Foster and the plastic wad/base on the bernieke are what accomplish this task.

It has always been my understanding that a Sabot Slug is for a rifled barrel.  The rifled slugs are more commonly used through improved cylinder bore barrels.  I have a younger cousin who about gave me a heart attack when he started loading up rifled slugs in his rifled barrel shotgun.  I corrected him and gave him the sabot slugs he needed for his rifled barrel.  An hour later he was standing over his first deer.  The jerk shot a girl.  Ha ha.  I still tease him about shooting a Doe.

Hello everyone,
 
I hunt here in Illinois where we can only use primitive weapons and shotgun slugs to hunt deer.  I have shot slugs through both kinds of barrels.  You are correct in saying the sabot style slug (i.e.- Rem. copper solid, fereral BRI sabot etc.) are intended for fully rifled shotgun barrels or barrels that have a rifled screw in choke.  The rifled slugs (i.e.- Rem. sluggers and such) are meant to be shot through smooth bore barrels.....the rifling on the slug itself causes the projectile to spin as the slug travels through the barrel.   On the sabot side, the plastic sabot actually engages the rifling and causes the whole thing to spin....once the projectile leaves the barrel, the plastic sabot falls away a short distance from the muzzle (same thing as a muzzleloader sabot).  
 
This is not to say you can't shoot rifled slugs through a rifled barrel.....I have a friend who does it.  I'm not sure what kind of accuracy he gets or how bad his barrel is fouled but it can be done.  I personally wouldn't recommend it due to the possible lack of accuracy and effects on the barrel.  Same goes for shooting sabot slugs through a smooth bore barrel.......I have done this myself and the accuracy factor SUCKS!!!!  There is no spin on the bullet at all thus making the weapon about the same as a civil war musket.    Main thing is this:  read the box completely before you buy slugs....most of them say on the box what type of barrel is recommended for that style of bullet!
 
Sorry this was kinda long...i tend to babble!!
 
Good luck,
 
S. Trapp

Thanks for the help guys  -Brendan