For rifles which were issued, nearly all had been overhauled and up-to-date at some time. Most certainly are a mish-mash of elements and had been upgraded as expected. Here are some of those elements. The trigger team on the M1 Carbine is in the sound metal housing. There is some https://www.safeheavenfirearms.com/product/ruger-m77-mark-ii-stainless-30/