One of the cannons in the Alamo collection today is an iron 8-pounder known as the “1842 Rio Grande Gun”. Found near Zapata in the 1870, this gun was donated to the Alamo in 1919. Local lore has long held that this gun was used by the Texans in the Battle of Mier in 1842, but that cannot be factual as the Texas expedition commanded by Alexander Somervell did not bring any artillery to the Rio Grande. This cannon was not used in the Alamo in 1836, nor in the Mier battle of 1842, but still has an interesting story to tell.
Click on the following link to learn more about this cannon.