From experience use the best fitting waisted pellet and not Lanes Cat Slugs as grouping will be abysmal.
I can provide you with a box of said Lanes for you to try if you wish.
As a side note, it was the introduction of waisted pellets that made rifled barrels come into their own, the earlier smooth bodied pellets had to much bearing surface to be any good.
The waisted pellets did not tumble on their way to the target, so were considered the better choice.
HTH 😊