I recently did some water expansion shots (no fabric) with a couple of factory defensive loads out of my 4" 624. They were the Hornady Custom .44 Special (180 gr. XTP) and the Winchester Super-X Silvertip (200 gr. JHP- current nickle plated copper jacket, not the older aluminum jacket). I know that water is not the best medium, but usually if bullets expand very well in water you can get decent expansion in gelatin + other.
Both loads were disappointing. The XTP just started to deform the nose, probably indicating that the XTP bullet is more intended for .44 Mag velocities than .44 Special velocities. I wish it was loaded by Hornady as a .44 special +P- it would probably be perfect. The Silvertip was even more disappointing, considering it is a custom bullet for that specific load and has a huge cavity. The projectiles showed even less deformation that the XTPs.
I am still looking for that ultimate .44 Special factory load for two-legged urban defense. Next to be tested will be the 165 gr. Corbon, with other possibilities including Federal's 200 gr. LHP, Speer/Blazer's 200 gr. Gold-Dot, and perhaps the Buffalo Bore 180 gr. JHP.
Just food for thought.