I see that Cornbread is still intent on fighting the world. It is a shame that these Steyr threads always go downhill from useful discussion to
somebody calling everybody that doesn't agree with him "stupid". There is a lot of good information out there, and there are far more intriguing subjects to talk about then the firing mechanism of the Steyr M-Series pistol.
Personally, I get sucked into these threads because I don't like disinformation being spread about such a fine pistol. If you personally don't feel comfortable with the sear and firing pin catch doing double duty as a firing pin block, then don't carry one or buy one. Nobody is trying to coerce anybody into violating their own conscience about what pistols they feel comfortable with.
I've already explained why I feel the pistol is DAO, but the information falls on deaf ears. It comes down to a difference of opinions on what signifies "single action" and what signifies "double action".
Cornbread feels that a firing pin spring that is completely compressed (or *mostly compressed* as in the case of the Steyr) automatically makes the gun "single action", and that is fine as his interpretation. I agree completely that the FP spring is compressed ~75-80% of the maximum value (though Handy came up with 72% on TFL) in the Steyr. However, Cornbread's definition os "SA" doesn't take into account anything that is going on with the sear.
The Springfield XD is considered "SA" because the FP spring is completely compressed (100%)
and because the firing pin is merely released by the sear. The 1911 works in the same way. There is only *one* axis of movement required to release the firing pin through its fully compressed stroke to strike the primer on the cartridge. Firing pin safeties and the like are engaged either by the trigger or the grip safety and really have nothing to do with the actual
release of the sear.
On the other hand, I consider the Steyr as "DAO" because the sear has *two* distinct directions of movement prior to the FP being released -- one rearward, and the other downward. I agree completely that the movement is minimal -- on the order of 1.0-1.5mm of movement in each direction, but the fact that the exact same dual-directional sear movement is required for each shot.
This is really splitting hairs, though, as the differences between the two mechanisms are subtle. Just because a pistol doesn't have a plunger-type firing pin safety does not necessarily mean that the pistol can (or will) have an AD. As has been stated previously, the sear catch is forced
forward by the tension on the firing pin catch as the slide moves forward -- in the
opposite direction of what is needed for the pistol to fire.
There is no way for the firing pin to independently fall forward and strike the primer -- even if the pistol is dropped on the muzzle -- because the FP is locked in place by the sear catch. The force required to hold the firing pin in place is minimal, and the forces on the sear and firing pin engagement during firing are minimal in comparison to the stresses being placed on other critical areas of the pistol.
The
only way for the FP to inadvertently strike the primer is if either the sear catch (not the sear...the catch only) or the FP catch were to suddenly and catastrophically fail. The design of these catches has been discussed
ad nauseum on The Firing Line, but suffice it to say that the tapered design of the catches places the greatest strength at the base of both catches where shear and bending forces are the greatest. The firing pin itself, if you take it out of the gun and play with it, is ingeniously designed for increased durability and strength.
Lifting the slide from the frame -- which is impossible unless the steel slide rails were broken (at which time you shouldn't be firing it anyway)
would release the firing pin. However, the forward-tapered design of the FP and sear catches would allow the firing pin to slide forward (relaxing the spring) as the slide was lifted to less than 50% tension. This would not be a sufficient tension to detonate a primer.
I feel like a broken record here, but I hope that some of this information will help other people looking into Steyr pistols to realize that the pistol design is quite ingenius and simple. None of this information will ever convince Cornbread, or Jimmy Mac, or Macman10, and other detractors of the pistol that the design is valid. The only person who came close was a guy named "MrAcheson" on The Firing Line who spoke of redundancy of safety features in the gun. Admittedly, the Steyr puts "
all of its eggs in one basket" with the sear/FP catch design, but as an engineer I personally feel that this critical system was designed with a sufficient factor of safety that the likelihood of the failures described above is almost non-existant and would end up being a fluke like a Glock going full-auto (oh wait, that was before the "voluntary upgrade"...
). It is like the wing of an aircraft: If one falls off you are going to be hard-pressed to fly it home, but they are designed with a sufficient factor of safety to prevent them from falling off mid-flight. The same goes for the Steyr.
Cheers.
