7th round stoppage repair

[RDS]

I asked this question on the M14 forum but did not get a complete answer. I have two M1s in the 30,000 serial range. Both were repaired for the 7th round stoppage.
How was the welding done as to not effect the heat treat of the locking lugs? Were the receivers reheat treated after the welding? Were the repairs done at Springfield
Armory or at the depot level. I researched TIG and MIG welding and they did not come into use until the late 1940s so I am surmising they were stick welded. Were the rifles proof tested after the repair. My concern is in firing these rifles.

[RCS]

They have been shooting these rifles that had the guide ribs repaired since mid 1940 without any known problems as a result of the welding. The rifles were only proof tested with the installation of another barrel. It is difficult to find receivers with the low guide ribs (even a few Winchesters had them in early Educational Order production) and these receivers are worth a lot more to the collector. Attempts have been made to remove the area built-up by welding the low guide ribs to look like original low rib receivers - but the small discoloration from the weld is still on the receiver.

About 99% of all the revision 2 receivers have the production high guide ribs

[RDS]

One of my rifles shows a larger than normal heat discoloration by the right lug. That's why I have asked. I have owned other early rifles in the past but none showed as a large heat discoloration mark as this rifle.

[Jersey Devil]

One of my rifles shows a larger than normal heat discoloration by the right lug. That's why I have asked. I have owned other early rifles in the past but none showed as a large heat discoloration mark as this rifle.

Photo showing the affected receiver attached.

[TJT]

I personally wouldn't worry about it and would have no issues shooting it.If it weren't safe it would not have been issued.
Jon