Sunday, January 17, 2021

The Uniqueness of Bullet Rifling Marks

 All good crime shows a firearms examiner matching a bullet to the gun, because every set of markings is unique.  Maybe not.  I cannot find the full paper but the beginning points out the unique nature of the rifling marks reflects the variations in the rifling tool.  They tested bullets fired from ten consecutive Ruger P-85 barrels.  I am not sure what the results were from having multiple firearms examiners do the checks, but the discussion makes me wonder if this uniqueness might not be as unique as generally assumed.  A barrel rifled last year would be quite different from one rifled today.  What about barrel 15001 vs. 15002 or 15010?


  1. apply "Daubert" standard to it.

  2. add to the fact that a simple pass with a stainless brush can throw some pretty big variances into the mix. Bullets before have significantly different marks from the ones after the brush.

    You can MAYBE tell that the bullet came from a rifle of the same type, but that is about it.

    Firing pin marks and extractor/other case marks are likely more distninctive than rifling.

  3. If one was concerned about rifling being evidence why would one keep the barrel or the gun?

  4. AAANNND "Sidecar" wins the cement bicycle....

    That is the exact thing I have said to a few folks when we discuss such hypotheticals. A chop saw and some battery acid and perhaps a swamp (or better several swamps) makes for an easy way to dispose of an unneeded or unwanted firearm.