Considering it's a Uberti and the first year of production to hit the market had loose arbor to frame fit..... guessing it'll need a going through first.
Well, that spring is a nice thought, wish it was about a 50 thousands shim, or better, a fitted arbor. Yes, the wedge can be lightly tapped in far enough to cam the barrel upward so that the cylinder is prevented from rotating.
And yep, its a Uberti and the arbor is loose in the frame. It both wiggles and rotates. Not a good deal, since the arbor also retains the recoil plate and firing pin assembly.
Finally, cocking the gun, and the mainspring is long enough it binds on the underside of the hammer just before full cock. It can be forced so the hammer notch and sear engage but such interference fit is not optimal.
Just for giggles. An original Lightning 38 grip strap just about fits. Dimensionally the 100ish year old grip strap is a perfect fit at the back of the frame and persactly the same width as the trigger guard. I think i can work with that!
Wolff reduced power mainspring drops the pull weight about 3 ounces to right under 2 lbs pull. A bit of fitting was required on length and width at the roller tip. Note the Uberti spring has been thinned, at the factory, on a belt sander....i wouldn't hold out much hopes for its longevity.
Also note the upper left rear frame ear, just above the grip screw hole. From the factory, a coil spring and plunger to operate the cylinder hand. Nicely done Uberti!
Just a little trimming of the Uberti Brass trigger guard where it meets the bottom of the back strap and a tiny tweek of the bend of the 1877 Lightning 38 back-strap.......and just like that, Birds Head grip frame. I still have to bring the uberti trigger guard width down to a match for the colt backstrap, as the back strap is 10 or 20 thousands thinner than the uberti guard. And, I'll need to adjust the lower screw hole or screw head, just a touch so the grip screw can be run all the way in.
Not a bad fit for parts that are 100 years and oceans apart.