Details
Frame defects such as cracking occur infrequently to the lightweight Model-50 and the 59.
Cracks in the bolt handle slot are the most recognized, but the magazine tube hole in the lower frame front leaves a thin wall that can split through the serial number (I have one here if anybody doubts the fact).
The action spring tube may come loose from the frame threads at the rear and allow the threads to pull out of the alloy frame, and I have had to renew the threads in the frame to permanently fix that condition.
When the steel tube comes loose from the frame, the aluminum extension is typically tightened to make the buttstock snug again rather than completely disassembling the mechanism to allow a proper tightening of the parts.
A quickie fix comes back to bite every now and then, and this is not a simple repair once a thread shred happens.
The barrel lug may pop off of the Model 59 barrel fiberglass surface every now and then. That is a minor weakness of what was supposed to be the highest strength barrel ever made for a commercial shotgun, at the time.
It was claimed to be able to withstand the 20 gauge shell drop-in with a 12 gauge shell fired after, and not swell the barrel. Care to try that with any other barrel and see the results?
Kirby