Must the caliber appear on a homemade firearm?
Not that I am aware of. One does not need a serial number on a firearm manufactured for personal use, either, even when selling it. Do you have a source stating whether or not it is necessary?
And checkout the last sentence on page 1 of this:
You may have to cut and paste these into your browser.
None of which address firearms manufactured by an unlicensed, private citizen for personal use.
Actually, the CRS Report is quite specific in that area.
Yes, it is:
By statute, FFLs are required to “identify by means of a serial number engraved or cast on the receiver or frame of the weapon” each firearm manufactured in, or imported into, the United States. Existing regulations establish more detailed requirements for how the serial number must be affixed, including the minimum depth and print size, and require additional information such as the firearm model, caliber or gauge, and the FFL’s name and business location.
Heck, look at your AR lowers, where it often says “caliber: multi”.
In a.nutshell and ime…no.
My AR is not homemade.
Precisely. You have a s/n,but possibly and probably “multi” for caliber on your lower, as you can run any of 7 differently chambered uppers…Home build, you don’t even need the s/n in most states.