You are very wrong again. If you receive a shotgun in your state that was manufactured in, let's say, North Haven, CT, and then you lop the barrel off to 12", that gun never leaves your state, and you or your cousin gets stopped with it on the front seat of his International, still in your state, you are in heap big trouble.
There is a law against sawed off shotguns and it has nothing to do with transportation. The case above has little to do about interstate transportation or serial numbers. Now if the shotgun was made and cut off before 1968 you might have some kind of a case.
No Montana does not make quantities of steel, but, ask a judge where a Smith and Wesson was Manufactured and produced and he isn't going to say Pittsburgh.
If I buy a billet of steel from a local supplier and make it into a gun where did I engage in interstate commerce? OK, I got the lathe and mill and tooling off a local Craig's list add.
The reason we have so many lawyers is because they can argue the fine points to the end of time.
For a bunch of 2 Amendment guys there are a lot of people here arguing for the BATF.
I did say I wouldn't make an effort to acquire such a gun. But, I do have a 1917 frame I am going to round butt. Serial number is in the way. My solution is I will cut it loose and and reweld it back in a new location. I could do it in such a manner that it is never completely detached. You could argue that I am altering the manufactures serial number after all what would stop me from trading serial numbers on 2 1917s and how would you prove it. I am not going to lose a minutes sleep over it.
If I was to restamp a serial number on a gun, the serial number would not be altered as it remains the same number, hence the manufactures serial number was never altered or obliterated. The manufactures serial number still remains on the gun. No where does it say the manufactures original stamping of the number, just the number. If I alter the gun in some way do I become one who remanufacture it? Remember the argument about Montana making steel? Did US steel manufacture the gun or did S&W? The steel supplier most likely had a heat number on the billet, is S&W guilty of a felony because they altered or obliterated a serial number on a "gun part"? If I mill out an AR 15 frame did I manufacture it or did the aluminum supplier, How about the place I send it to to have it precipitation hardened. If I drop my gun and put a dent in the serial number is it now a felony to own it. How much obliteration does it take. Does a light polishing for reblue cause this because it partially obliterates the number. Can I restamp or recut the original stampings to redefine them? How much wear can there be on said stampings? Even if I were to file them off I could make them reappear by using something like ferric chloride, so were they "really" gone? Define removed for the court please. Where does it say in the law that the butt number counts, but the one in the yoke cut out doesn't. When I bought my pre model Highway Patrolman at what point was I informed that the number on the butt was the serial number and the one in the yoke cut out wasn't? I have had to correct FFL holders on this issue 3 separate time. I'll bet the majority of present day LEOS don't know that the number in the crane cut on pre model S&Ws is not the serial number. LOL
All this is ripe for legal discussion.
Show me the case law where this kind of stuff has been decided by a judge. Then, remember that a federal judge's decision in say the 9th district is not binding on a judge in another district.
To me this is all just a theoretical discussion. I find it entertaining. My girlfriend says I am very good at it and it is what keeps lots of lawyers and legal researchers employed.
Ex post Facto has little to do with domestic violence. Domestic violence was a crime when it was committed. It was not a made a crime when it was added to the list of those who could not own a gun.
Once again I don't want a gun with a messed up serial number. If I had one I would be very careful with it, but I wouldn't worry about anybody breaking my door down or sending me to prison over it. I might be temped to completely remove messed up number and restamp it and reblue, but not worth my time and I have lots of grinders, polishers, stamps and even a small bluing tank.
I certainly would not announce it on the internet.