I agree with 2-p that there is little reason to use a plain low carbon steel alloy (like 1018 - 99.82% iron and 0.18% carbon and th th th th that all, folks, nuttin' else in there) for a modern gun action. There are modern alloys that are better and can still be case hardened. If, however, you are a traditionalist, you can use 1018 with confidence. The case hardened low carbon steel receiver has withstood the test of time for sporting arms.

DDA