A suppressed .223 is plenty for 75 yards and about like firing a 22lr. You can fit a 56mm scope on an AR style carbine without losing your cheek rest. The only trouble is convincing someone who's used to an /06 to try it.

https://www.aldeer.com/forum/ubbthr...;Board=1&main=265910&type=thread
https://solo300.com/products/gen-ii-solo-300-upper-no-barrel?variant=45373019914389
https://www.shawcustombarrels.com/shop/product/223-wylde-16-portless/666