The geometry of the hammer spring and the bolt carrier can sometimes conflict. If the BCG does not have enough momentum (due to light loads), the bolt speed slows down just enough for the hammer to follow the bolt forward rather than locking back on the sear. Additionally, factory AR triggers vary wildly in quality; the generic mil-spec trigger included is often rough.

The BP-12 utilizes a standard AR-15 trigger group, which is a major selling point for those who want a crisp, aftermarket trigger. However, integration is not always seamless.

Bullpup triggers are almost universally worse than standard rifle triggers due to the long linkage bars required to connect the trigger to the sear. The BP-12 is no exception—but it has unique problems.

For the average shooter expecting a "buy it, load it, shoot it" experience, the BP-12 is a nightmare. It fails with cheap birdshot (the most common practice ammo). It requires specialized disassembly tools and knowledge. The magazine springs fail. The trigger is terrible. The customer service is reportedly slow to respond.