Oliver Sudden,
Any image much over 1000 pixels wide is hard for some to see on the board, so your post can be underappreciated. I shrank a copy for you and hosted it on the board.
Here are several online picture resizing services (no need to mess with a photo editing program for that function anymore):
http://www.resize-photos.com/
https://resizeimage.net/
http://www.picresize.com/
The work looks nice, especially for a quick approach. I am reminded, though, that P.O. Ackley, who had a degree in metallurgy, said he found in his destructive testing that a lot of re-heat-treated Mausers and other rifle receivers tended to have microscopic cracks that made them weaker than they had been, originally. This was despite the conventional wisdom of his day suggesting the re-heat treatment would correct deficiencies in the original heat treatment. It may not matter at shotgun pressures, but firing a proof load still might be prudent.