In my The Truth About The Gen 5 Glock article I wrote about the new Gen 5 barrel. I told a story about a gunfight I got to participate in involving a couple of armed robbers and a team of guys armed with polygonal barreled pistols. The bad guys ended up as large slabs of ballistic gelatin on legs, but the CSI guys were not able to determine whose rounds hit which bad guy due to the inability of the polygonal bores to mark the bullets sufficiently for a match.
I got this from a correspondent who is in the CSI biz:
"I just read your blog post about the new Gen 5 Glocks. Some info on the CSI front.
You are correct that previously, nearly any bullet fired from a Glock would not be identified to a specific pistol. However some time ago Glock started marketing barrels that were designed so the bullets could be matched back to a specific weapon.
The guns that had these barrels were not very common. Glock continued to work on developing barrels that would allow matching of the bullet to the pistol. The technology in the Gen 5 barrels is very similar to what is used on the G42 and G43. Glock referred to these barrels as "Glock Marking Barrels".
I have personally made several IDs (and the forensic firearms field has also made many IDs) to Glocks with this type of barrel. For what its worth I have not seen any Gen 1, 2, 3, or 4 Glocks mark bullets well enough for ID (again this is due to the type of polygonal rifling they used), but the G42 and G43 you can, and I strongly suspect it will be the case with Gen 5 guns, and all Glocks from this point on. Thanks for all you do."
Interesting information and good to know.
Incidentally, those wanting new non-Glock barrels to retro-fit to their Glock 19, 17, 34, and 43 - for any reason, you can find them here -