Im a bit surprised the Lantac straight pull bolt AR and other similar makes arent getting more traction when the "not an AR" discussions come up. It seems like a very simple conversion and uses nearly all standard AR parts besides the slick side upper and bolt carrier, and I believe a standard one could be converted. The gas port and tube may need to be blocked/removed in some locales, not sure, but neither would be hard to do.
https://www.lannertactical.com/strai...ven-ar15-rifle
GIF showing it in operation.
https://33.media.tumblr.com/5cc18d90...tutso1_500.gif