Quote:
Originally Posted by m102404
I'm not sure that your description of things is correct...or that I'd do a better job at describing things. 
Part#66 is critical to the functioning of the system.
When the hammer goes forward it strikes the knocker...the knocker is spring loaded to snap back rearwards, but is held forward. You can observe that by cocking the hammer back just a bit and you'll see that the knocker stays forward (i.e. it would still be holding the knocker valve of the mag down...as gas would be flowing).
If you were to take the trigger mech apart you would note a little bump on the hammer. This bump interfaces with the lower leg of Part #66. The bump bumps the leg and part #66 kicks the knocker out of position and it springs back (retracts back). When it does this...that effectively shuts off the gas from the mag. You can observe that by cocking the hammer back bit by bit until part#66 causes the knocker to flick back into it's reset position.
I did miss in my previous e-mail that it is possible that a sharp corner of aftermarket Part#66's can wear out the nub on the hammer...causing things to fail. You can see if that nub is worn by taking the part #66 out of the trigger mech and by cocking the hammer while the trigger mech is out of the receiver. You should be able to look into the hole on the side and see the condition of the nub. A pre-emptive move would be to round the contact edge of aftermarket CNC'd part #66's...so that it doesn't wear the hammer. All it needs is enough of a bump to kick the knocker out of position.
Compare a stock part #66 with some of the aftermarket CNC steel part#66 and note the rounded corner of the leg. |
Thanks for the reply Tyson, sorry about my poor explanation regarding the function of Part 66. I'll try to choose my words more carefully
So the other day I was just observing the function of Part 66, and watching how it moves as the hammer is cocked and this is what I observed.
When the hammer is pulled back, the nub on the hammer pushes the leg of Part 66, which causes this part to be pushed upwards. When this happens, the knocker is allowed to retract since it is spring loaded and uninhibited by Part 66. This effectively, cuts off the gas flow. Correct?
Now lets take the same scenario but remove Part 66 from the equation. When the hammer is cocked, wouldnt the knocker still retract since it is spring loaded? Wouldnt its retraction still operate without Part 66?
The reason why im asking all these questions is simply this: Sometimes when the hammer is cocked by the BCG, the knocker does not fully retract. I realized that I would have to cock down the hammer with greater force in order for the knocker to completely retract. After some observations, Part 66 is not being pushed high enough for the knocker to fully retract, that is why a greater force to depress/cock the hammer was required. A slight upwards push on Part 66 is all that is needed for the knocker to retract fully. However, I was just reading your description above:
"When the hammer goes forward it strikes the knocker...the knocker is spring loaded to snap back rearwards, but is held forward. You can observe that by cocking the hammer back just a bit and you'll see that the knocker stays forward (i.e. it would still be holding the knocker valve of the mag down...as gas would be flowing)."
and this may perhaps be normal. I was thinking about increasing the height of the nub on the hammer so that it can push Part 66 higher, allowing the knocker to retract more effectively. What do you think?