My Southern rifle had the lock, barrel and all the other steel parts browned. The brown job was fairly good on the barrel but looked hit and miss on the other parts. After asking questions here and doing some researching on the good ole "net" I tried a few different formulas:
1. lemon juice, bleach, vinegar and salt - OK but not very consistant and would rub off easily.
2. Muriatic acid diluted in water - poor result, streaky.
3. Naval jelly - worked GREAT !
I left it on for about 20 minutes and the parts have an almost aged pewter look and finish to them after oiling. This was just about what I was looking for. I will post some pics soon. I like it way better than the brown.
By the way I left the barrel browned, my choice.