They should be safe, but they might not be accurate. The problem with shooting lead is that it might not fit your barrel properly. That can cause the bullet to not spin and stabilize properly. If you do a quick youtube search for a 10mm hardcast video by Hickock45 he demonstrates this with the 230 grain DT WFNGC load in a Glock 20.
I personally handload their 200 grain variant. It works great in my G20 barrel. I personally think it is a better weight for 10mm.
EDIT: Found the video: