An armed group stole an estimated 7 million rounds of ammunition being transported through central Mexico last week, but the manufacturer says that most are small-caliber bullets that will likely be useless to cartels.

The gunmen robbed the trucks carrying the ammunition, which was bound for the United States, on June 9, intercepting the route in the municipality of San Luis de la Paz, according to local reports. The drivers and security personnel were not harmed during the robbery, and the trucks were later found with the trailers emptied.

Last Friday, a representative for the company said in a statement that almost all of the bullets stolen, about 98.5%, were .22 caliber, which are mostly used for target practice and for hunting very small game. These bullets do not match the type of guns that members of Mexican drug cartels typically use, which tend to be high-caliber rifles such as the AK-47 or the AR-15, or they use 9 mm firearms, according to The Associated Press.

"These will be of no use to them, given that they don’t use these weapons," said security analyst Juan Ibarrola, a spokesman for Tecnos Industries.

The ammunition, which is manufactured in the Mexican city of Cuernavaca, is sold in the U.S. under the brand name Aguila.

According to Insight Crime, some of the ammunition was for high-powered weapons such as the AR-15 or M-16, but it’s unclear what portion. No group in Mexico has claimed responsibility for the crime as of Tuesday.

A previous high-profile case of stolen ammunition in Mexico occurred last July, when about 28,000 bullets vanished from a police force in the town of Silao, though the ammunition was later returned.

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