Well sometimes the agricultural approach is all that's needed. If you want a more recent parallel, torqueing up of barrels on SA80 was always, "wazz it round till the expensive Torque wrench goes 'click', and if the barrel gas block isn't vertical then graunch it round until it is".Probably!
I asked a WW2 armourer how they fixed No1/4 receivers where the bolt head was jumping the rail. Was it gauged and then cast?
"No. We put an axe head in the mag slot and hit it with a lump hammer. That bent the rail back into contact."
And, what happens if you twist the receiver during rebarrelling? Was it gauged and then cast, etc?
"No, you just put a bar through the receiver and twist it back the other way."
Sadly, the chap passed away before I could complete my gunsmithing apprenticeship....