The Truth About Guns has been investigating the Bushmaster ACR recall. As you know, a small number of examples were going fully auto. According to Bushmaster customer service, the rifle’s firing pin was the problem. “It was too heavy for certain types of ammo where the primer stood proud,” the agent told us. “We’re putting in a lighter pin and a stronger spring at no charge to the customer. Our current turnaround is two weeks.” So, the question is this: why didn’t Bushmaster test the ACR with all types of ammo before they sold the gun? The answer may be simple enough . . .
The ACR was a military-spec weapon first, a civilian gun second. In the Cerberus era, where cost cutting is king, what’s the bet they skipped that ammo testing part of the process? And here’s something else we noticed . . .
Check out the image of the firing pin above and this one from the manual [click here to download the pdf, page 29].
Notice that these firing pins have a little “shelf” at the top. Presumably, that would stop the pin from releasing forwards after firing, preventing the gun from going full auto, no matter what the ammo.
An ACR owner tells me their pin (from a gun well along the production run) was shelfless. (If anyone has an image, please send it to firstname.lastname@example.org). What happened? Why the change? What type of pin does the military spec ACR use, and when did it use it?
More to the point, I’d like to see some proof that a lighter firing pin—rather than a return to the original design—is the answer to this problem.