I have a couple Stevens 44 1/2 actions in which I'd like to install a set of CPA double set triggers.  I have never did this type of work before.  Would this project be doable with a stock 44 1/2 action?  That is, an action with standard triggers.  If so, what modifications beyond installing the triggers themselves will need to be done?  Obviously I need some education here.  Many thanks in advance.

Basically you will need the trigger set, lever and maybe a hammer fly.

Drill and files for tools.

If you use a CPA lever the top hole for the link will need to be drilled out to the correct size.

Stevens seems to have shipped the 44 1/2 with the fly installed, whether it had single or double triggers. So there’s is a good chance it is there, unless someone lost it, or almost worse, installed it backwards. A cut away drawing will be very helpful.

The trigger assembly will need to be fit. If it is too wide, very common, you have a choice of fitting the trigger to the action, or action to the trigger. Best to fit the trigger if you ever want to use the original again and for collector value.

Most likely the front through bolt will not line up, elongate the holes in the trigger assembly.

The front of the lower tang, that holds the triggers, will probably be too long. If so, it will interfere with the link reaching bottom, full throw of the lever. This will be the most work. Be careful of shortening the front of the lower tang, there is a screw there.

The CPA lower tang is much different than the original Stevens. The front is a channel and the vertical portion is thicker. Therefore the inside width is narrowed. This again prevents the link from reaching bottom and the lever from traveling to full throw. You might get lucky and have enough throw to load cartridges and extract, but not likely.

Again you need to modify the tang or the link. There is a set screw for a spring that can also interfere. You can remove some material from the radius of the link, but removing too much will keep the hammer from moving back far enough to set at half cock.
The other option is too narrow the portion of the link that will pass between the groove in the tang.

A straight tang generally fits well enough in the stock. Again it’s a choice of having a poor fit and modifying the stock so the original trigger no longer fits.

A pistol grip and a curved lower tang will probably need the tang bent to fit the stock. Again you might get lucky, but don’t plan on it.

The fit of the lower tang into the action is critical to have correct. If it’s too tight, the clamping pressure can be enough the prevent the set trigger to go into the full lock position. This allows the hammer to slip and cause a discharge.

Continued

If you're missing the fly, CPA has them in stock for $7.00.