...done it. With 10 pumps, in .22 cal with 14.3 pellets, it was producing in the 630fps range. Many issues have to be addressed...
The hole to secure the valve needs to have a screw shouldered, or a steel ring to prevent movement (the hole is bigger than the 1377 hole).
The rear of the tube needs to be trimmed down and the front; this allows the use of the 2289 barrel band/front plug for the front, and for the rear the 1377 plug.
Other than that, the valve holes do line up, i.e. securing hole and transfer hole. You will need a breech with the forward securing screw location too, as the tube has an odd slot.
It is indeed possible to do. I was going to build a rifle using the 2260 trigge pack and stock, etc., but used the parts to build two different guns (modded a 392 and built a custom pistol). Had the unit up and going, fired several rounds out of it, then gutted it.
"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."