IIRC Weaver cut the shotgun of slightly longer than the minimum length. The agent then used a cloth tape with a little stretch to get the barrel just under the minimum length.
Weaver was not convicted on the charge.
So BD are you a LEO or one of those who all ways sees the LEOs as in the right. Come to think on it , that would make you a progressive.
With further thought, the agent who measured the barrel is responsible for all the deaths that followed. He should be in prison awaiting execution.