That 1972 [0226b] example reminds me a lot of mine with the casting larger than the finished receiver dimensions to allow milling of the surfaces, with the micro gas bubble flaws in the sides of the receiver showing up as well.
Funny, I never considered that one cast, just a huge mystery to me. It was interesting to see that one with my morning coffee as it hangs four guns above my laptop.
That one I got as a barreled receiver only. It now sports 90% parts from one gun....and wears (until I can locate a replacement at NOT today's prices...) the receiver cover from my cast DB, which is currently donning a scope mount that only fits that gun....which is also a hot mess of non original parts. The 0226b is also on my Covid to-do list for headspacing the new bolt.
(That got interrupted by my 'new' Classic that I am about to get elbow deep on decosmolining the stock....pics soon!)Love the photo spread Phosphorus32....I saw that and left the tab open a couple days ago before any responses....pleased to hit refresh today for the discussion.