This is an adapter to use a Thompson 1928 bolt in a m1a1. I'm using it in an airsoft aeg to make a dummy replica.

I started with a 1928 bolt by MikeS on GrabCAD. I reworked it using dimensions from a real m1a1 bolt. I moved the charging handle hole to the slot for the blish lock so no modification to the bolt is needed.
https://grabcad.com/library/thompson-1928a1-bolt

Real m1a1 bolt are expensive and hard to find. Stripped 1928 bolts are still available. The slot for the blish lock is almost completely covered by the cocking handle.

I also made a printable m1a1 bolt.
https://www.thingiverse.com/thing:5174461

The airsoft cocking handle knob can be reused.
https://www.thingiverse.com/thing:5172034

The Fusion 360 file is included.