What is the test for admitting or denying evidence of dangerous weapons found in the possession of a defendant?

"Where ... evidence is of very slight (if any) probative value, it's an abuse of discretion to admit it if there's even a modest likelihood of unfair prejudice or a small risk of misleading the jury." United States v. Hitt, 981 F.2d 422, 424 (9th Cir.1992). "Testimony concerning dangerous weapons found in the possession of a 'person charged with a crime, no part of which depends upon the use or ownership of the weapon[s], has consistently been regarded as prejudicial error.' " United States v. Green, 648 F.2d 587, 595 (9th Cir.1981) (per curiam) (quoting United States v. Reid, 410 F.2d 1223, 1226-27 (7th Cir.1969)).