If you seriously want good quality soft brass gun hardware then take the time to go through the relaxed and personal rituals associated with buying from Reaves Goehring, in Lancaster County (not the town), Pennsylvania. You will learn a great deal about Kentucky rifles in the process, and get a fine product. Mr. Goehring is a gentleman, and a most knowledgeable one.
I will not provide contact or other details, feel it best you get them yourself.
When you buy some metal casting, whether sand or investment, it is very important to choose one of the alloys which that foundry regularly casts. I can assure you from work experience that this is true of large industrial customers as well as home shop guys.
The terms "brass" and "bronze" had, more or less, some meaning in Biblical times. We still use the words but . . . In 2004 the SAE listed over 500 different alloys, whose names include various combinations of the words copper, brass and bronze. The alloying elements used now cover the alphabet from the most ancient, Arsenic, to the newest, Zirconium.
Leave the details to Mr. Goehring.
Or buy from otherwise fine dealers & get something more or less yellow which you can file, sometimes easily, sometimes not. All I can tell you about any of them is please do not heat them to bend them. Almost all brass/bronze castings or sheet/bar have a little lead added. This helps machining - and engraving. If you heat the thing to bend it you may have made tiny puddles of molten lead which run along the grain boundaries & make the stuff crumble when you bend it. Anneal if it helps you. Do all your bending and pounding near room temperature.