Ahab has a good post pointing out the very close resemblance to H&K’s 4.6x30mm round to the .17HMR in terms of ballistics. Since H&K has decided to disrespect the shooting community in the US by refusing to offer civilians versions of most of its product line, it’s hard for me to get excited about the MP7. Actually, I’m very skeptical of most of the PDW concepts I’ve seen out there today. I don’t quite see the point in a round that will penetrate soft body armor, but will likely not stop the attacker beyond that.
The only PDW I could see myself getting is this one. To me, if you want better than a submachine gun penetrating power in a lightweight package, the existing 5.56×45 NATO round is just fine.
Knight Armament’s PDW is pretty cool… I got to fondle one a while back (while getting paid, too!) and was quite impressed. It’s externally quite similar to the AR platform–two pins to connect upper receiver to lower, trigger and hammer pins in the same configuration… but the lower’s just a bit smaller than the AR. It’s a dual (I think I remember that… though it sounds crazy) gas piston design, with an AK bolt. The cartridge is a 6×30 (I think) with a ~60 grain bullet at 2600 fps (maybe 2500?) out of an 8 or 10 (can’t remember, but there’s two lengths… a 6 or 8″ and an 8 or 10″ version)
They claimed the compensator was really effective (and their video showed that compared to an M4… but of course, the M4 has more recoil to begin with… but it still seemed to work well, nonetheless).
I’d never had much of a desire to do the whole SBR thing, but if/when they make a civvie version, I just might have to. And the KA representatives were quite nice to humor me in letting me field strip it and look at all the fiddly bits and talk ballistics with me.
*that “out of an 8 or 10” was supposed to be “out of an 8″ or 10″ barrel”–but I’m sure you figured that out.
One of the things that’s always turned me off to PDWs is the fact that they all take boutique ammunition. I like the idea of one that uses 5.56×45. The big drawback there is the 5.56×45 NATO is a rifle cartridge, so a lot of energy in the powder will be blown out as flash and noise, which is a waste, and a drawback. That would make full-auto controllability an issue, certainly, but for civilians that won’t really matter.
But 5.56×45 NATO means I can practice with it without spending an arm and a leg for a boutique round that costs more than a dollar per trigger pull. The FN and KA PDWs look pretty cool, but I couldn’t afford to shoot them.
I also think the PS90, or any other PDW for that matter, is pointless if you don’t do the NFA thing to get the SBR version. Otherwise it’s just another rifle.