Re: M40a1 build guide
The M40's purchased by the Corp in 66ish were 6 digit non prefix that the later M40A1's were built from. Those that have been damaged, destroyed, lost, worn out or more added according to George at GAP were first C prefix, then some E's and the last are G prefix. No mention of B ever. Also the smooth bolt handles with no checkering were originally intended for the plain jane Model 78 that replaced the 788 for a short time. Cheaper bluing, no checkered knob and a hardwood instead of walnut stock, otherwise the same. Some of the bolts ended up in 700's however as I have seen some at gun shows and for sale on Gunbroker etc.
Also I am near positive that all M40's used standard Remington bottom metal. Not until the M40A1 was the 2pc Winchester used. Some are using a modified ADL stock with pressed checkering however I have never seen one with enough 'meat' in the forend to inlet it for Remington's Varmint contour barrel and look descent. The original M40 stocks were the Varmint Special model less tenite tip/grip cap, checkering and with and oil instead of polyurethane finsih. They were not ADL stocks worked over that I have seen. The later cut checkered ADL stocks DO have a bit wider forend and will leave enough material top side after inletting for a HB. I put my 40XR 22 rimfire is in one and barrel is about .050 larger muzzle diameter (.880) than a Remington Varmint/M40 barrel(.830). Don't know how the newer ADL will look after the cut checkering is all sanded off though. It cannot be steamed like the press checkered model. The one I am referring to slops rearward at the tip instead of being rounded.
All this garble probably only makes things more confusing? Only similarity with M40 vs. the M40A1 was the M40A1's were built initially using recievers from M40's and being 308's!!!! Stock, swivels, barrel contour, floorplate, and eventually the scope and mounts are all different.