The cannon has a quite a history. It is really small. Compared to what comes to mind when cannon is mentioned. The bore is approximately 1 1/4".
As told in the vid. The cannon was "spiked" and later reactivated or "unspiked"
When told to "Come and Take It", the Mexican Army had arrived and the cannon fired upon them. Due to enlarging the flash hole, during the reactivation, the cannon belched almost as much fire and smoke out the top as was out the front. But, it was enough to convince the Army they didn't want to confront a cannon.
A "gunsmith" headed to California told the partisans that he could repair the cannon. He wrote oyears later, in a book, how he had examined the damage done by the spike and then bearing unsoiled. He repaired that damage and made a bushing to reestablish the proper flash. Detailed drawings were put in the book.
When the call came in for reinforcements at the Alamo, a new carriage was made and the cannon mounted. The group of volunteers proceed down the King's Highway to San Antonio.
In their haste to build the carriage, the wheels were inadequately greased. At a creek crossing, the wheel bearing screaming, seized. A hole was dug in the side of the creek bed and the cannon buried. The volunteers marched in to the Alamo.
Jump forward to 1919.
A torrential had fallen and water roared down the creek. A mail carrier, on his route, comes to the creek crossing and sees something sticking out of the mud bank. He goes to investigate and finds the barrel. The wooden carriage long since rotted away.
He digs it out. Thinks it is cool. Puts it in his mail car ( Model T, most likely ) and continues his route.
The barrel changed hands, a couple times and around 1936 ended up in possession of a 12 yo boy. A Dr had seen the cannon and wanted it for a display. He made the boy several offers, finally getting to one the 12 yo could not refuse.
The Dr was examining his "new toy" and discovered the bushing and repair. Having read "gunsmith's book, he began to get excited.
He loaded up and went to Univ of Texas, History Dept and asked them to examine. He gave no provenance or hinted to his beliefs.
The UT examined, cleaned, X-rays, and documented. The asked the Dr for what he knew about where the cannon found.
Finally, issuing their findings.
The metalurgy and style was period correct. The bushing and repair was identical to the drawings and description in 'smith's book. The location of where the cannon was found. They were convinced that this IS the Come and Take It cannon.
The Dr had a replica carriage built and asked the Gonzalez Museum if they would like to display the cannon.
"This is the story is the truth, I have been told, by a friend that grew up in Gonzalez and his Father was friend to the Dr. Other versions may vary"