Brass you say, yes.yes.
Silicon bronze’s density is 8.53 g/cm3 (0.308 lb/in3).
The density of brass is 8.4 to 8.73 g/cm3 (0.303 to 0.315 lb/cu in).
Refs from the Google machine.
Being virtually the same as silicon bronze, doesn't that make the GP trim kind of heavy?