I guess I don't understand the purpose? Why would anyone be cycling live rounds just to cycle live rounds? Buy or make dummy rounds.
The design of the AR is a floating firing pin. As soon as you close the bolt on a live round you get a dimple b/c the pin has come forward and tapped it, however it lacks the energy needed to detonate the firing pin. Once the hammer strikes the firing pin is when the proper amount of energy is transferred to cause it to fire. The a slam fire can occur is if the firing pin is physically stuck in the protruding position and the mass of the carrier coming home gives plenty of energy. The hammer could also follow the carrier down which could also cause the gun to fire, but again... all these are major malfunctions.
If you have to go to all the trouble of taking the assembly apart to place your block in place, and then put it back together when you want to shoot; why not just take the firing pin out, do what you need to do, and then put it backin ? You can insert a BCG minus firing pin and do all the test cycling you need to do without issue.
The design of the AR is a floating firing pin. As soon as you close the bolt on a live round you get a dimple b/c the pin has come forward and tapped it, however it lacks the energy needed to detonate the firing pin. Once the hammer strikes the firing pin is when the proper amount of energy is transferred to cause it to fire. The a slam fire can occur is if the firing pin is physically stuck in the protruding position and the mass of the carrier coming home gives plenty of energy. The hammer could also follow the carrier down which could also cause the gun to fire, but again... all these are major malfunctions.
If you have to go to all the trouble of taking the assembly apart to place your block in place, and then put it back together when you want to shoot; why not just take the firing pin out, do what you need to do, and then put it backin ? You can insert a BCG minus firing pin and do all the test cycling you need to do without issue.