[Hunterj50]

Does anyone have any experience with Trail Boss for 38-55? The Hodgden site lists a max of 7gr for just 911fps. There is also a formula they post on the site that figures starting loads for other cartridges not listed. Using this foumula it indicates a Starting load of 8.7grs and then work up from there.

http://www.imrpowder.com/PDF/Trail-Boss-data.pdf

I really like TB in my 45-70 and was wanting to try it in a 38-55 but looking for a bit more velocity than 900fps. Any thoughts?

 

[80hp]

Trail Boss was designed to be used for low velocity loads by cowboy shooters. They needed a bulky powder that filled the case to prevent double charges, and was not position sensitive. It works great for that purpose. You will not get high velocities with it.
For more velocity, try Unique. There are videos of two guys on Utube shooting long range with .38-55's and Unique.
M.