For CAS a plated bullet is not allowed, so a cast, or swaged, lead non gas checked bullet is what is required. Velocities are low. I cast my own and to save time I also buy bullets. The X-Metal bullets are coated, with an coating from a reputable supplier.
http://hi-performancebulletcoatings.com/
I have loaded 125 gr and 147 gr X-Metals bullets in my 38/357 hipguns and rifle. I don't have any issues, haven't noticed any smell, but I only shoot outdoors. I did notice a little bit of what appears to be burnt paint or coating in the barrel. When I say a bit I mean I use a magnifying eye loop to see it. This residue brushes out of the barrel easily, one pass maybe 2.
The 147 is in reality just an oversized 9mm bullet, smooth, no crimp or lube grooves. I shoot it in my '66 lever gun, so I roll crimp it. I seat and crimp in separate steps, no issue, the coating is tough. I bell my cases before seating the bullets, just as I do with cast, with either a LEE powder through or Lyman "M", nothing excessive. I asked X-Metal if I could resize their bullets, they did not recommend it. That being said, I sized and lubed some of the 125 gr bullets and shot them with well beyond CAS loads, and was pleased with the results.
I can see no reason why I wouldn't try them in if I were you. In fact I plan on loading up some in my 9mm Browning Long. I also will be buying more for my CAS guns. My only complaint is that I would like a larger selection, and more calibers. Like some bullets for my 44 Spl/Mag and 44-40 guns.