Hey viscous-Peanut
THe original DOuble Action pistol was the Waltehr PP/PPK pistol
of 1929 - it combined the first shot capabillity of a double action
revolver for the first shot - i.e. the loaded magazine is placed in the
gun - operate the slide back and forward to chamber a round. the
hammer is cocked. Engage the thum safety on the slide and
it is Condition One, that is loaded, Cocked & Locked however if
you thumb the safety off, the hammer falls to a half cock position
and then unlike when the hammer is fully cocked where you would
call it a single action pull because it is just releasing the cocked hammer
it goes to Double Action mode - a longer trigger travel that cocks the hammer fully, for that first shot. subsequent rounds are back to the
shorter travel single action trigger pull.
The first full size service pistol with the same operation as
above was the Walther P-38. The Browning HI-Power of the same
decade has the same Single Action only trigger action as a
1911, once the round is chambered thumb the safety on and
it's Condition One - Cocked and locked, and that's the way it is
carried by some people. I mention the Browning Hi-Power vecause
it hwas the first full size/service pistol to have a high capacity
magazine.
Roll time forward to 1975.
The CZ 75 combined the high cap.; magazine with a grip frame
much like a Browning Hi-Power but it also had a DA/SA trigger action
Double action for the first shot then Single Action for subsequent
shots HOWEVER it has thumb safety which is ONLY a thumb
safety iit simply is on safe or is off safe, ifor the first shot to be Double
Action the user must let the hammer down by operating the trigger
while easing the hammer down with another digit perhaps with the
opposite hand. then the it can be carried with the hammer down and a
double action pull for the first shot, then single action.
Still with me?
THe CZ 75B is a mod. to the original design in that it has a firing pin
block so that if you dropped the gun, the firing pin won't by
inertia flung forward and strike the primer causing the gun to discharge.
This was added in 1993 and most if I am not mistaken further
variants of the design include the firing pin block.
so, a CZ 75 or 75B first shot Double Action or first shot Single Action but
it should have had the thumb safety employed for safe carry then you can
just fire single action, and if you aren't through with the magazine you have the option of putting the thumb safety on, or easing the ahammer down to go back to DA for the first shot.
Variants
CZ 75BD the D suffix means it no longer has a thumb safety, it has been changed in function to be a Decocker. First shot DOuble Action subsequent shots SIngle Action and when you pause to reholster instead of thumbing the safety on, or easing ithe hammer down manually, you operate the Decocker and the hammer goes to half cock OK?
Another Variant,
SP-01 is SINGLE ACTION ONLY
THis means it works like a Browning HI-Power or 1911, it is
Single Action only, load a mag, rack the slide and the
hammer is cocked - put the thumb safety on to holster it
for carry, when drawing to fire it thumb the safety off and
it's SIngle action triggerr pull every shot.
Some shooters with the heavier DA first shot have a different
Point of Impact with the first shot versus the subsequent lighter
and shorter travel Single Action trigger pull. This is why some
makes or models have been modified to Double Action (trigger pull)
Only or a DAO pistol.
I hope that clarifies things - the AMbidextrious safety has nothing to
do with the DA/SA trigger action options.
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