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In the late 60's, I upgraded my newly-aquired ($95) .243 Model 700 Carbine (20" bbl) with the BDL bottom metal.
FWIW, all short-action Model 700's use the same bottom metal & followers, interchangeably for all the chamberings based on the .308 Winchester parent case (.243, .260, 7mm-08, .308, etc).
I bought the BDL trigger guard & floorplate directly from the Remington Parts Dept, then simply cut out the walnut floor of the ADL blind box magazine well from the inside.
There was a little additional inletting/fitting of the bottom metal, especially between the front of the magazine well and forward guard screw.
I used the original follower, mag spring, and guard screws w/o issue.
Long story, short - order the short-action parts for your .243 M700.
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