As is mentioned in the episode itself, the method by which Dr. Astin and the Lieutentant use to match the bullet to the murder weapon has been dismissed as being scientifically unsound because the chemical composition of its particles can be matched directly to the other bullets in the same series and thus cause confusion as to which weapon is the murder gun. I learned this from the TRUTH IN JUSTICE website.
S 8 : Ep 24
Aired 5/11/83 (49:12)
S 8 : Ep 23
Aired 5/4/83 (49:17)
S 8 : Ep 22
Aired 4/27/83 (49:12)
S 8 : Ep 21
Aired 3/23/83
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