Enhanced but small image that Ted posted, from
https://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=638769

[Linked Image from photos.smugmug.com]

I'm sure a Parker expert knows when Parker Bros. went from brazing

[Linked Image from photos.smugmug.com]

To silver soldering?
https://www.shotgunworld.com/threads/parker-28ga-vh-value.570016/

I don't know if anyone has sent the remains of one of these guns to Dewey Vicknair, or if he would be willing to provide an opinion, but he no doubt could explain the failure

BTW: another alleged cracked frame Flues wink

[Linked Image from photos.smugmug.com]