John, according to Remington, their Copper Solid Sabot Slugs should only be shot using a rifled barrel or rifled choke. One of those through a fully rifled 870 took care of a biggish wild boar.
On the other hand, I have in front of me a box of "SAGA Bala Expansiva" (http://www.saga.es/angles/home.html) that are specially made for use in smooth bores with any type of choke. I have tried them and they are very accurate and have fantastic penetration. According to the manufacturers they also work very well with rifling.
JC(AL)
