Here are the Eley specifications, and they are boomers also; pressures are not reported
https://www.eleyhawkltd.com/products/game-cartridges/vip-bismuth

I did not find a U.S. Eley dealer, but Maxam Outdoors owns both Rio and Eley Hawk. Here are the Rio Bismuth loads
http://www.rioammo.com/en/rio_ammo/products/non_lead_cartridges/bismuth