In the days when military surplus was a bunch cheaper a common conversion especially in states that didn't allow autoloading rifles for deer hunting, was to block the gas tap on an M1 carbine. This converts the carbine into a straight pull bolt action. Some outfits offered calibers specifically designed for this conversion such as a 30 carbine necked to 224 bullets. I believe it was called a 5.56Spitfire but am not sure. Military carbines are way to expensive for that today but the Universal carbines are fairly cheap and it's an easy conversion. Atering a bolt action to take the much smaller carbine case head is a chore and most often ends in failure.