Ballistics — ATF Inconclusive & CBLA
The autopsy bullet jacket fragment is the physical piece tying "a rifle shot killed Charlie Kirk" to the seized Mauser 98. The ATF laboratory report returned INCONCLUSIVE — the central forensic tension in State of Utah v. Tyler Robinson. Tyler Robinson is charged, not convicted.
Fragments recovered
During autopsy, examiners recovered one bullet jacket fragment and four lead fragments. The jacket is .30 caliber class. See Medical — Trial & Autopsy for wound context.
Class vs. individual characteristics:
- Class — shared by a category of ammunition/firearms (rifle not excluded).
- Individual — microscopic marks unique to one weapon (positive match requires these).
ATF report — September 17, 2025
Per the report summarized across site materials:
| Item | Description |
|---|---|
| Fragment | Autopsy Exhibit 6A — deformed jacket |
| Rifle | Seized Exhibit 1 Mauser 98 |
| Conclusion | INCONCLUSIVE — could not identify or exclude as fired from Exhibit 1 |
| Rifling | Consistent with numerous makes and models |
Defense filings in March 2026 cite this as exculpatory, invoking Trombetta/Youngblood preservation doctrines in a seal motion later opposed by major media (gag & sealing). A judge unsealed the ATF report in 2026 per Fox News while the comparison remained inconclusive.
Casing vs. jacket — do not collapse
Court commentary distinguishes:
- Spent casing at scene — reportedly matched the seized Mauser.
- Jacket fragment from body — inconclusive rifle link.
Prosecution also cites DNA on trigger, casing, cartridges, towel, screwdriver per charging narrative. Defense argument is narrower than "nothing matches" — it targets the bullet-to-rifle link needed for the kill-shot theory. See Proof Not Tyler — ATF.
FBI Virtual Comparison Microscopy (VCM)
State reportedly moved the fragment to the FBI lab for VCM — 3D scanning fragment vs. virtual test-fired round. FBI notes describe a fragile fragment with detached pieces in packaging; unfolding may require tools that could add marks.
Defense reportedly requested independent expert presence or videotaping — FBI declined per defense motion reporting (FBI Ballistics).
CBLA commentary
Comparative Bullet Lead Analysis (CBLA) was banned as unreliable FBI practice. Citizen investigators allege CBLA-style reasoning resurfaced in this case — an attributed theory in X threads (Gun & Bullet), not a court finding.
Separately, cartridge casing engravings are described as consistent with a rotary tool / Dremel per defense materials — a manufacturing or alteration question, not proof of tampering established in court.
June 2026 contempt link
Prosecutor media statements calling evidence "ample" despite inconclusive jacket comparison contributed to Christopher Ballard civil contempt per Judge Graf (prosecution team).