Bullet Used in Charlie Kirk Killing Doesn't Match Alleged Weapon, Defense Claims

There's a new twist in the case surrounding the assassination of conservative activist Charlie Kirk ... new legal documents claim the bullet used to commit the crime does not match the rifle tied to suspect Tyler Robinson, TMZ has learned.

According to the legal docs obtained by TMZ, Robinson's defense team argues there’s a discrepancy between the ballistic evidence and the weapon prosecutors say is connected to Robinson ... who's facing multiple charges -- including aggravated murder and felony discharge of a firearm causing serious bodily injury -- in Charlie's slaying.

Robinson's attorney claims the Bureau of Alcohol, Tobacco, Firearms and Explosives conducted a summary report which indicates the ATF was “unable to identify the bullet recovered at autopsy to the rifle allegedly tied to Mr. Robinson.”

The motion continues ... "Although the State has not indicated an intent to produce this report at the preliminary hearing, the defense may very well decide to offer the testimony of the ATF firearm analyst as exculpatory evidence."

The defense also says there are multiple categories of forensic evidence that are still incomplete, according to their discovery request -- and until they get the full case files and testing protocols and have their own experts review them, they won’t be able to determine whether that evidence is actually reliable if it ends up in court.

In the docs, Robinson’s defense says it's drowning in evidence -- claiming prosecutors have already handed over around 20,000 files. The haul includes about 61,500 pages, 31 hours of audio, and more than 700 hours of video across 5,000+ clips. Bottom line, the defense says it’ll take at least 60 days just to get through the first pass.

Robinson's lawyers also recently made a push for the trial to be televised, saying ... "Keeping court proceedings as public as possible helps to quell and contradict the tide of misinformation," while secrecy fuels conspiracy theories.

As we previously reported ... Robinson allegedly confessed to his father that he shot and killed Kirk on the Utah Valley University campus on Sept. 10. Robinson's father reportedly told a youth pastor, who happens to work with the U.S. Marshals, and Robinson ultimately surrendered at the Washington County Sheriff's Office, around 10 PM on Sept. 11.