Will the FCG detonate 5.45×39?

Yes. Typically Russian, the primers on  5.45×39  ammunition are very hard. Our FCGs can have a high-energy hammer fall that exceeds MIL-spec by as much as 35% and is very capable of detonating/igniting 5.45 x 39 ammunition without breaking a sweat. To achieve this best-in-class high energy hammer fall, use the Blue toggle springs, which also produces low trigger pull weights in the range of 2-1/2 to 2-3/4 lbs.

For some, understanding how an extra pair of springs can simultaneously achieve very low trigger weights and still produce the highest energy AR hammer fall in the industry is mind bending. But, that’s precisely what the HIPERTOUCH® 24 family of FCGs for the AR rifle does. It’s kinda like a compound bow. Hammer cocking force is very high at the beginning, then it drops off as the hammer is fully cocked, just the opposite behavior of every other AR hammer. When the hammer is fully cocked, the force is lowest, therefore the pressure on the sear is lowest, therefore the pull friction is lowest, which the shooter feels as lower weight. That’s it.