Blue/Black Finish on a Lock?

[Bill-52]

I want to put a dark blue/black finish on a flint lock, which I've never done before (nor on a barrel, for that matter).  I've been planning on using LMF and their rust/scald/card process but thought I should check here first.  Would one of the commercial bluing agents be better?  Or are there even other alternatives I should consider?

This rifle will be shot often, so durability is important.

Many thanks,
Bill

[satwel]

I recently finished a barrel with an old unopened bottle of Wahkon Bay tru brown that I had. I carded and boiled between coats and then a final boil. The barrel ended up with the black color I was hoping for. Should work on a lock as well. I think the boiling is the key. I have not used any other rust brown products so I can't make a comparison. I've always had good results with Wahkon Bay tru brown. I used it on a L&R Classic lock 12 years ago, without boiling - so it's a deep rust brown, and that finish has stood up fine. No wear or thinning evident.

[Acer Saccharum]

Rust blue is VERY durable. Quick blues are NOT.

There is no easy way around it, rust bluing is a lot of work.