Thanks Guy's! Slug was 38 grs. Further modded the mold to cast at 34 grs. No, shooting slugs won't harm a barrel. LOL! I have tested NSA, Air Velocity Sport and D-Rig's and all shoot well.
The .25 is choked, but very little. About a Thou and a half. Simply size to the choke, not the bbl. In truth, a choke is only good for two things. First fixing issues in a bbl. that has bad spots in it. CZ bbl's have no such issue. In fact the Uragan came with a fully lapped and polished bore. Never seen that in any factory gun before!
Secondly, helping with the wild differences in pellet sizes. I don't shoot pellets, so I do remove the choke on most of my guns. The Uragan didn't need the choke to be removed. Woo-Hoo!!!
Most important thing for shooting slugs is to slug the barrel and order or size slugs to fit. It it has a choke, always size to the choke. Not he barrel proper.
Knife