@tjnewton. I think we had a PM about this? I am now convinced...
After recreating this problem and spending way way to much time on it, I now understand what RSR and bone steel and others are saying. For a while I thought I did not need the TAB (bolt carrier side plate), and maybe I don't, if I never do rapid fire box drills, or 1-5 drills, etc. ...but if I do want to rapid shoot, and manage the trigger depressed, I better get all my VZ58s "tabbed". So here is my feeble attempt to explain:
The following description is without the
bolt carrier side plate present (a.k.a. "Tabbed" )... And with the safety set to the Fire position...
The toe bone is connected to the foot bone but the ankle bone may be twisted if the leg bone is moving faster than the knee bone, ahhhhh, OR...
If the disconnector in down, while the trigger is either released or all pressed all the way back, the sear is up (or should be up) to catch the striker. In really simple terms: 1)the disconnector and sear are on a see-saw (disconnector is pushed down, sear goes up...disconnector goes up sear goes down.), 2) the raised sear grabs the sprung striker, 3) the trigger enables the sear to drop down.
When the disconnector is engaged (pushed down) by the bolt carrier traveling forward over it, the disconnector position enables the opposing force supplied via the feather spring to act and push/keep the sear up, thus capturing and holding the nose of the striker firmly so it is not able to travel forward with the bolt carrier (a.k.a. da "gremlin"). This cycle happens in an approximate time of much less than 1/60th of a second (using ~800 rpm design cadence of the vz58) and is designed/engineered to work (and
should always work) while the trigger is either released and fully forward, OR if the trigger is fully pressed back and held in place. This is a machine gun that was bastardized to semi-auto function -- like an AK, the trigger should be held back, then released to the reset point IMO.
Semi-auto, Closed bolt, one Feather, is the name of my American Indian friend:
The bolt carrier side plate (or the "tab" as many call it) increases both the amount distance of engaged carrier travel over the disconnector-- and therefore the amount of time -- that the disconnector is pushed down (and the sear is up on the see-saw) during the carrier forward travel, thus guaranteeing that the striker nose is stopped and held securely by the sear.
Why da Gremlin comes out with the trigger at the reset point:
What I believe I have observed: When you press the trigger back and then slowly release it to (but NOT past) the trigger reset point (observed by that audible 'click and tactile feel in the trigger finger) the disconnector is now in a slightly forward position and not completely engaged or in the down position and the opposing force of the feather spring on the sear is still partly but not fully engaged. Because the distance (and thus timing)from the point where the sear and striker nose interact, to the point where the un-tabbed carrier engages the disconnector is now changed, the FCG timing is now vulnerable and the sear may be just low enough at that fraction of a time to miss catching the striker nose which already went past and caught the A train uptown. In other words: ipso facto bark bark woof woof -- you reset the trigger and press but es gibt keine schiessen.
With 4 VZ58 (CSA and OOW) variants while utilizing an un-tabbed carrier (carrier without the bolt carrier side plate present), in any one of them, this phenomenon can easily be demonstrated any time, at will at the work bench.References:
http://cz-usa.com/hammer/wp-content/uploads/2014/04/vz-58-military-manual.pdf (look at this!)
p.11 and p.13,14
My own hours of testing and obsessive observation.
So, that probably cleared it right up for you. (NOT!)
I could make a raw video and attempt to demonstrate this if you think it might be more clear.
