http://www.waffeninfo.net/verschluss/bild/tiltblockani.gif Well, I suppose it's only supposed to be a tilting bolt action cycle of operations, but I can't for the life of me think of another tilting bolt design with a piston attached to the bolt carrier. Animations make these sorts of things much easier to visualize.
That was fascinating to watch. Like genesis through simplicity. Kind of a thing of the past. Do you have an animation of a tilting bolt design without a piston attached to the bolt carrier?
I found this: YouTube - SKS Firing Animation‏ But it's not very good since it's too wide to make much out and the bolt isn't actually shown to tilt.
Thanks, that was good enough. For some dumb reason I was trying to visualize the action with no piston at all even though that obviously wasn't what you meant to imply. I now see your point. Why attach the piston if it isn't necessary. Just a matter of engineering preference I suppose like some MP-40s with floating firing pins and some with fixed ones.
On the K43 the piston is not attached to the carrier, which allows the top of the receiver to be open when the bolt is retracted so the rifle can be reloaded with stripper clips. That's one good reason, I suppose, although the Garand has a piston attached to the carrier that gets around this by running the bolt carrier along the side of the receiver rather than on top of it. Other possible pros and cons include that having the piston attached to the carrier (I believe it's pinned on in the STG, similar to an AK) means fewer loose parts to lose in the field while performing maintenance, while keeping the piston separate means that it doesn't move as much as the carrier and thus the rifle's center of gravity shifts less during firing which renders it more controllable (although it's a decidedly second order effect). I don't think it makes that much difference one way or another.