[Parts] PD Trade-in Colt Bolt Carrier (No bolt and firing pin) - $35 + $5 FRS

There is absolutely zero functional difference between full and semi bolt carriers used in an AR-15. Neither is "better" or "worse" and many struggle to correctly differentiate the two unless they were side by side and labeled. Still, upon hearing "MIL Spec, Full Auto" assumptions are made that it must be somehow better. It's not, it makes absolutely no difference except perhaps as a marketing tactic.

The Only difference between a full auto and semi auto bcg is the location of the cut on the lower lug at the rear of the bolt carrier. The cuts function is to trip the auto sear, and the location of the cut ensures the timing of when the auto sear is tripped. Moving the lug cut on a full auto carrier any further than +/- 0.0005" creates an out of spec and now semi-auto carrier. For sales purposes the cut is generally shifted rearward 1/3" or more. In either case most people can't even correctly identify the difference unless the lower lug cut is moved back significantly, or removed completely.

Given two otherwise identical carriers, one with the rear lug cut in the correct place to trigger an auto sear, and the other cut further to the rear, there might be a weight difference of a few grams simply because more material is removed from the semi auto carrier.

In reality, the weight difference is negligible due to the wide range of materials, design, and coating combinations offered by manufacturers to the civilian market.

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