Le Pistolero wrote:One thing on the chart that I don't entirely understand is the "Pin Block."
I guess that's a safety feature on the firing pin........is it a critical feature?
Ya, it's a safety ... the firing-pin/striker moves along the bore axis ... the firing-pin-block safety moves 90° to that axis, to either block the firing-pin/striker's movement, or allow it!
Typically, the trigger is the means by which it's activated/deactivated ... at rest, the firing-pin/striker is blocked!
This is what's also known as a "
drop safety" ... if the gun were dropped ... depending on a great many thing ... the mass of the firing-pin/striker could be such that a chambered round could be fired!
On 1911's w/o such a safety, a titanium firing-pin is sometimes used ... at which, it lacks sufficient mass, to fire ... in such a situation!
... or ... don't drop the gun!

ETA: basically most any semi-auto pistol ... including more than a few 1911's ... manufactured since around the 1980's (
if not before) ... have this type of safety! ... and offer no comparable models, without it!