I have to ask you how you welded the guard on? I have talked with many machinists, tool & die makers, welders, etc. who always state that without knowing the type of steel being welded, they cannot guarantee the results. Guessing what rod or wire to use can cause erosion, splatter, cracks, and holes in the pieces according to some craftsmen I have approached with projects on hundred-year-old+ guns.
I know enough to weld two pieces of steel together using stick welding, but MIG, Flux-Core, and TIG are mysteries to me. I am curious what type of welding you did and what materials you used and how it worked out?