i agree with obi , i dont consider it a stage unless the sear are engaged so i think its a single stage .
now about the removal of the trigger spring (circled) in your pic , i been a firm believer for a long time that without the spring (see thread below) , it increases the chances of gremlin due to increase friction and wear .
try this test (only non-rest) , you will find the results interesting .
remove the top cover, striker and bolt , leave the muzzle on the floor , using the top cover pin as a measuring point , lift the back end of the rifle till the top cover pin is 6" off the floor , slide the carrier back and let it slide forward , does it sucessfully slide all the way forward ? now do it at 8 , 10 , 12 & 14 " .
heres my results :
height of pin: rifle A(1) .....rifle B(2)....rifle A (3).... rifle B(4)
6" ...............failed............failed............failed............failed
8" ...............success.........success........failed............failed
10".....................................................failed............failed
12".....................................................success.........failed
14"........................................................................success
note: (1) rifle A with no known gremlin with trigger spring.
(2) rifle B with know gremlin with trigger spring .
(3) rifle A with no known gremlin with trigger spring removed .
(4) rifle B with known gremlin with trigger spring removed .
as you can see from the data , without the trigger spring , the carrier requires more force to get over the sear disconnect (SD) and thats bcos of the increase interference placed on the carrier forward movement by the SD , the trigger spring reduce the rise in the SD . having said that , it doesnt mean that having the trigger spring you wont get the gremlin , all im saying is without it , it will increase the chances of getting the gremlin . well, takes my take on things so i like to leave my trigger springs in.
http://www.canadiangunnutz.com/forum/showthread.php?t=169256