As a result of Irwin-Pedersen being unable to complete its contract, the Saginaw Steering Gear Division of General Motors took over the former's plant in Grand Rapids, Michigan, and continued production beginning in April 1943 using leftover Irwin-Pedersen components along with those from Saginaw. To distinguish receivers manufactured between the two plants, the Grand Rapids produced receiver heels were marked with "S'G'" instead of the standard "SG" used by the main Saginaw, Michigan, plant. This specific receiver falls within the 1st production block, part 'B', (serial numbers 1,798,000 to 1,875,039) produced from July to September 1943, after the 2nd production block (serial numbers 3,212,520 to 3,250,019) was completed in conjunction with the 1st production block, part 'A'. Features unmarked, possible replacement, winged blade front and "S" marked 'L' flip peep rear sights, a "7-43/ordnance bomb" Underwood barrel, unmarked type 1 barrel bad with replacement swivel, "S'G'" blued flat top bolt, "S'G'" type 2 slide, "S'G'" type 3 trigger housing with "M" magazine release, "SW-S'G'" sear, and "S'G'" type 3 hammer. Fitted with an oiled walnut 'high-wood' stock, marked "RSG" in the sling channel and "ordnance bomb/boxed S'G'" cartouche on the right of the butt, topped off with a "RSG" two-rivet handguard and "PM-IP" buttplate, along with a blued "SS" magazine. Includes a web sling, steel oiler, and rubber magazine cover.

Very fine, retaining 85% plus original parkerized finish, with some spotting/freckling showing on the barrel and receiver, brown patina on the blued bolt, minor edge wear, and light cycling wear. The stock is also very fine with a few light handling marks, a glued crack at the 'high-wood' channel, and defined stamps. Mechanically excellent.