Did deaths in 2020 caused by foreign objects placed in the rectum surpass total deaths from "AR" (Armalite Rifle) fire in the last five years? No, that claim cannot be supported with available data: As of April 16, 2021, there is no publicly available database of the number of deaths caused by people having foreign objects in their rectum, nor is there data establishing how many people were killed by the assault-style rifles colloquially referred to as "AR" rifles, which was short for the original U.S. manufacturer: Armalite Rifles.
In 2020, there were 287 cases of people dying - by putting foreign objects in their anus. This is more people in single year than people who have been killed by ARs in the last 5 years.
This is what the post looked like on Facebook at the time of writing:
(Source: Facebook screenshot taken on Fri Apr 16 19:58:34 2021 UTC)
Lead Stories reached out to Dr. Robert W. Beart, M.D., a board-certified colorectal surgeon and author of a scientific article about the management of foreign bodies in the colorectal region. In an email asking if Dr. Beart knew of any publicly available databases or achives where Lead Stories could find the total number of deaths caused by having a foreign objects in the rectum, he responded, "I am not aware of a database."
According to the FBI statistics for murder by rifle during 2015-2019, the total number of people killed was 1,573. "Rifle" is the statistical category that includes 'AR' and other assault-style rifles. Lead Stories efforts to reach the FBI for 2020 data were unsuccessful.