https://firearmshistory.blogspot.com/
This is a source I use for information on some technical aspects of guns. It is not easy to navigate. You pretty much have to open up every month to see what was posted or use a google search to find what you are looking for.
For example 416 stainless used in gun barrels is martensitic not austenitic steel and typically less durable than Chrome-Molybdenum steel alloy. https://firearmshistory.blogspot.com/2010/06/barrel-making-making-modern-steel.html
Metal Treatments: Browning and Bluing. https://firearmshistory.blogspot.com/2010/08/metal-treatments-browning-and-bluing.html
The formula for the solution used for the Brown Bess musket (taken from General Regulations and Orders for the Army, 1811) is as follows:
Nitric acid - 1/2 ounce
Sweet spirits of wine - 1/2 ounce
Spirits of wine - 1 ounce
Blue vitriol (a.k.a. copper sulphate) - 2 ounces
Tincture of Steel - 1 ounce
You get the picture. Lots of technical trivia.
That's interesting, and I like the recipe for browning solution. I think the ingredient "blue vitriol" is kind of funny though — in sounds like angry, bitter criticism delivered with a lot of profanity and vulgar language! I don't know if I could take 2 ounces of pure blue vitriol! Yikes!
You could if you were a villain. 200 years ago that would have been pronounced Vile Lien with a literal meaning.
Check out the other technical information there. There's lots more.
This looks way more interesting than my other assignments.