With a little bit of luck, you don't even need special frame blocks, barrel blocks, or a vise to replace that M28 barrel.
1. Remove the cylinder and crane.
2. Drive the barrel pin out.
3. Use a couple layers of duct tape to protect the barrel lug finish.
4. Using a hard plastic-tipped hammer, rap on the LEFT side of the barrel underlug to loosen and remove the barrel. It is held in with no more than about a dozen ft-lbs torque. A couple of solid raps while holding the frame in your palm should do it.
5. Use a bore brush to clean the threads and frame areas.
6. Lightly lubricate the threads of the replacement barrel and thread into place.
7. Rap on the RIGHT side of the underlug to tighten the barrel. Check to make sure the front sight is indexed vertical.
8. Reinstall the barrel pin.
9. Reinstall the cylinder and crane and cycle the action.
If you are really lucky, the barrel-to-cylinder gap will be around 0.005" to 0.010", and within S&W specifications.
If you are a little lucky, the gap will be too small and need to be filed a bit.
If you are not that lucky, the b-c gap will be too big and the barrel will have to be turned on a lathe to make it fit.
