I'm hitting brick wall in my research for Marine uniforms, weapons, and training in the ten years immediately before the Civil War.
Any suggestions would be greatly appreciated.
See if you can find a copy of Rankin's book on Uniforms of the Marines. Its out of print but you can get a used copy through Amazon.com or through inter-library loan. While not perfect, he discusses changes in uniforms, weapons and equipment up through Vietnam. I have a couple of other recommendations that I can provide when I get home this evening.
Up until about 1860, enlisted Marines wore a light blue shell jacket and trousers, with a dark blue round cap. Officers wore a dark blue frock coat and either light blue trousers, if serving with troops, or dark blue trousers if not (generally this meant majors and above, and staff officers at HQMC). New regulations went into effect in late 1859, but like the Army it took several years for the unifroms to get into the seabags, especially for those Marines aboard ship on foreign stations until they could return to the States.
Firearms included the 1842 and 1855 muskets.
Training was pretty much the same as the Army - a lot of drill. Since "Napoleanic" tactics were still pretty much the norm, all they had to know was how to march from one linear formation into another and load and shoot on order. Once aboard ship, Marine detachments might receive some training in manning one of the big guns. It depended on the ship's captain.
US Scout
Bvt Brig Gen, GAF