Hopefully your search/quest for data has been fruitful. I played with Tin Star briefly, but had discouraging Es and Sd. I found this odd as most of the forum scuttlebutt is positive.

I assume that you will be loading a 200 gr cast or swaged bullet. In 44-40 have have had good luck with a LEE 429-200-RF. It comes out a bit heavy for me, but out performs a Lyman 427666 by a country mile.

I don't have a hip gun, only a rifle, a '92, keeping pressures real low is not my first criteria, accuracy and velocity are. My first load, with Unique, around 9.5 gr was real accurate, and below the 1400 fps, the max for CAS, but, the targets at the range I shoot at like a bit less velocity. Reducing the charge of Unique ruined accuracy, so I finally settled on 5.5 gr of Red Dot, low enough in velocity and accurate.

So, that's the long winded way of saying, that the 44-40 is somewhat fussy about the load it likes, but it is potentially a pretty accurate caliber.

My suggestion for Tin Star would be to look at data for Unique, (Tin Star is somewhat like Unique, although not in looks). I would also try a magnum primer as your load will rattle a bit. I assume you have a chronograph, IMO you are lost without one, especially working below book data. I\m by no means an expert, but the load development I've done was enlightening. I ended up with a load of app 4 gr of Universal with a 132 gr cast bullet, at around 780 fps. Es and Sd were very much dependent on the brand of brass and the primer. Below book loads can be funky, I wouldn't go there unless I needed to. CAS loads, with a 750 fps target velocity, are a challenge with light bullets.

In the 44-40, the case is of large capacity, and a 200 gr bullet is light for caliber.

Nitro