"I'm essentially trying to get at a product that would already have huge aftermarket support (even before it's invented ) coupled with a compact non-SBR package. For what PCCs are (defensive ones anyway), they should be SBRs, but that's such a hassle even if it is legal (which it isn't in my state). In which case I present my designs as bullpups to shorten the over all system, to bring an out of the box legal defensive PCC."
I'm glad someone here knows what PCCs are good for. Too many people think they compete with M4s directly, when in reality it is that the M4 is a radically different tool that has been pressed into the role SMGs used to have, and both have their merits and shortcomings.
Looking at the drawing, it appears like a very doable setup. I'm guessing the action would be a simple blowback, but with a bolt that uses Glock extractors, firing pins, and ejectors. Those are your three wear components that will need replacing right there, so utilizing them will make maintenance very simple and cheap. Keep in mind that an unlocked bolt will need to be quite a bit heavier than the Glock slide, check our Orionshammer.com for some weight estimates for various cartridges (most are on the heavy side, though).
For the trigger system, you may find the Glock striker is not the best solution. I say this simply because the trigger group is shifted very far back from the grip, so you would have to run pushrods not only from the trigger, but from the safety as well --bad juju for trigger quality. Instead, I'd use another off-the-shelf FCG like an AR or AK group, and use a tension cable to run it so you have better pull, while still using common components.
Mag well is easy enough to fabricate, the mag release might need some thought to get a solution amenable to a bullpup layout. The receiver will basically be a tube, I'd make it square simply so you can make the bolt a bit shorter while retaining the necessary weight for operation in the corners.
Ejection is definitely something you'll want to think long and hard about. I think bottom ejection in bullpups is the way to go, simply because it can be done as violently as a side-eject using a fixed-blade ejector without irritating the shooter (much). The bolt travel will increase (which helps with recoil) so the round can eject just behind the magazine well out the bottom. If you run into length issues with the bolt and buffer spring, consider using a telescoping bolt --that will get you as short as you need to be
Very cool concept, I like to see people looking into new ideas. Too many folks who only think in terms of what's on the shelves and spoon-fed to them out there. Just an FYI if you wish to pursue this further, numerous Glock-magazine blowback guns have been constructed by members on WeaponsGuild, though most of them are forward-magazine varieties as I recall. Huge wealth of information there, but they
will expect you to reciprocate by working towards completion of the project and documenting your progress. Small price to pay, IMO.
"why wouldn't you just design the parts that work best?"
Because internet commandos who think you need a store of a dozen extractors to keep the gun running through the Apocalypse and the New Age will claim the gun can't be trusted without widely available replacement parts. In my experience, this is mostly done to further the hegemony of existing platforms --
their platforms-- and is a much smaller issue than what people make of it. Lots of folks won't buy VZ58's because they don't take AK mags, even though the guns are fundamentally different from each other. A blowback carbine is fundamentally different from a Glock, but if a number of small wear-prone parts like firing pins and extractors are already available in abundance, that's one less phony claim that can be leveled against it.
I'm sure they'd just fall back on the old saw "but my AR (again, justifying something they already own that's utterly unrelated
) can do everything that PCC can do, and brighter/louder/more expensive to boot --why not use that instead?" :banghead:
TCB
