Seems odd.
http://www.foxnews.com/us/2014/11/12...hem-in-danger/
Nearly one-third of the U.S. Customs and Border Protection's 16,300 M4 carbine rifles were tested by the agency's office of training and development, which determined that more than 2,000 had the potential for malfunction. The rate of nearly 40 percent was "more than we are comfortable with,” said CBP Deputy Chief Ron Vitiello.But in the meantime, Border Patrol agents are dubious about the department's claims, given that the guns' manufacturer, Colt, has not issued a recall. And they are vehemently opposed to "pool guns" -- weapons shared by two or more agents.“All you need to do is pull out the old firing pin and put in the new one and the rifle is ready to go,” he said.
Vitiello said that may be the case, but the work must be done by a specialist.
“It may be easy to replace a firing pin, but these are things that should be done by a professional,” he said.