What's the Point of an HK MP7 or FN P90?

Discussion in 'NFA Firearms and Accessories' started by Sebastian the Ibis, Nov 12, 2017.

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  1. Sebastian the Ibis
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    Sebastian the Ibis Member

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    One of the latest fads seems to be procuring a smaller PDW that is capable of penetrating body armor better than standard pistol calibers. The HK MP7 and FN P90 seem to be examples 1A and 1B of this fad.

    Steel core pistol ammo accomplishes the same result, and doesn't require a new platform and stocking a new caliber. Is there any real benefit to 5.7x28 or 4.6x30 over steel core 9mm in an UZI, MP5 or any other SMG (or even a pistol)? If there is a benefit, I can't believe it outweighs the logistical benefits of not adding a new caliber to supply chains.

    While I understand that AP pistol ammo is unobtainable for civilians in the United States, but so are full house 5.7x28 and 4.6x30. Moreover, HK and FN are selling these to military and law enforcement who are not subject to these restrictions.
     
  2. Ryanxia

    Ryanxia Member

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    Those platforms mentioned have been around for a long time actually and fill niche roles. The P90 was developed for NATO and meant to replace the 9mm cartridge not the 5.56 and offers an extremely small package with AP capabilities. The ambidextrous bullpup design is the desirable attributes of it (one of the reason I enjoy mine being a lefty). Also being able to have a 50 round standard capacity magazine is a nice bonus for the same small package. But the P90 was developed like 30 years ago, while today you can fit a full power 5.56 or 7.62x39 into almost as small of a package. Having something that fits in your jacket with 50 round magazines remains a nice perk though. Also has a bit more manageable recoil for full auto fire than a rifle round.
     
  3. MachIVshooter
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    MachIVshooter Contributing Member

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    Both offer far better penetration of body armor than any 9mm round. Remember, for armor penetration, velocity is king, and the 5.7 & 4.6 have it all over the 9mm. The smaller cross section also lends to better piercing, and the lighter projectiles mean lower recoil, ergo a more controllable full auto PDW. Futhermore, the smaller, lighter rounds mean more in a magazine and more on one's person.

    I'm not a huge fan of the P90 or MP7, but I'd take them over most subguns, especially where your opponent is likely to be wearing body armor.

    None of them will defeat level IV, of course, but then, neither will 5.56 or 7.62.
     
  4. Danoobie

    Danoobie Member

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    I like my PS90, because the Sheriff took over an hour to arrive, the last time he was called to my neighborhood. You are pretty much on your own, out here.
    The FN PDW system, comprising the 5.7 pistol and the PS90, with no spare mags, has 71 rounds of ammo.
    VS a 9mm pistol-18rounds,+ AR-30 rounds=48 rounds of different ammo. An added plus is the FN PDW is
    a 22 caliber, close defense, much less risk of collateral damage, hundreds of yards away.
    Another real advantage is the system is very compact and light. Obviously not a ground
    pounder's first choice, but great for the tech, or artillery guy, who may have to repel
    a hostile force on their location. I have to respectfully disagree, with personal experience,
    I feel it's well worth the extra trouble of the new caliber to the supply chain. They
    both point reasonably well, (pistol better than the 90) have little recoil, shoot clean,
    and are easy to field strip and maintain.
     
    Last edited: Nov 13, 2017
  5. MachIVshooter
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    MachIVshooter Contributing Member

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    They have far less application in static defense with semi-auto operation, where weight is of little consequence (ARs can be much lighter than a PS90, BTW) and controllability on full auto irrelevant. In semi-auto, you can't get rounds on target any faster with a PS90 than an AR carbine, probably slower due to fixed (crappy) ergonomics and an even worse trigger. If your rate of fire will be similar, the more effective cartridge, both on armor and tissue, is the logical choice.

    Also, the integral sight on the PS90 is garbage, and the design is not conducive to a different one, end up with a (lack of) cheek weld similar to mounting an optic atop the AR carry handle.

    Furthermore, it's pretty silly to argue magazine capacity, since ARs can be equipped with mags from 5 to 100 rounds. Throw a Surefire 100 or Beta-C in the AR, now it beats the PS90 by a factor of 2.

    If you just like it, that's great, but don't kid yourself about it being more effective than a 5.56 carbine. I'll take my 10.5" AR every day and twice on Sunday over a PS-90 for a variety of reasons. And if I wanted a compact bullpup, it'd be the RDB or Tavor.
     
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  6. grampajack

    grampajack AR Junkie

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    As mentioned, both platforms have been around for quite some time. It started in the late 80's when NATO floated a wish list for a new pistol/subgun combo that could penetrate soft body armor. They had this whole list of requirements that were pretty outrageous, which is how we ended up with the P90 and Five Seven. HK then came out with the MP7. NATO determined the 5.7mm was superior, and that the P90 was superior to the MP7, and they were set to be adopted and standardized. The Germans, however, threw a fit, demanding that the MP7 be adopted instead of the P90, which pretty much killed the program.

    It's a shame, too, because the P90 on full auto with solid copper bullets is nothing I would want to be on the receiving end of. I don't think it would ever replace 9mm, but for certain applications it makes a lot of sense. Even the PS90 with a 10'' barrel is a very handle little home defense weapon. It's such a small package and having 50 rounds on board is a great thing for a gun that you're just going to grab and go. Factory 10'' barrels are very difficult to come by, though, and there's only one guy making halfway decent ammo for it.

    Contrary to popular myth, you can actually buy and possess SS190 black tip without breaking any laws. It's a mild steel core just like M855. FN just won't sell it to civilians. Some has leaked out, but it's very pricy. FN's loads actually suck, though. You're looking at 7-10'' of penetration in gel from their LE loads (SS198LF and SS190) because both rounds are based on an aluminum core ~30 grain bullet. The best ammo was developed by a private bullet maker in I'm wanting to say Denmark (don't quote me on that), and a version of those designs is currently being produced by EA here in the US. The SS197 (sporting factory round with blue tip) is actually better than the restricted LE loads, believe it or not. It gets 15-18'' in gel, but it's not armor piercing.
     
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  7. dogtown tom

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    It's not really a fad if no one buys them..........and few LE/military ever did.




    Neither proved more popular than pistol caliber subguns. Agencies that moved away from subguns moved to the AR.
     
  8. dogtown tom

    dogtown tom Member

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    This.
     
  9. Sunray

    Sunray Member

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    HK MP7 and FN P90 are for military and European police. "PDW" is a marketing term just like 'tactical'. Both, in their civilian guise, are just big kid's toys that mayor may not pay for the development. Usually not as only the U.S. allows civilians to own stuff like them.
    "...penetrating body armor..." That'd be strictly a military thing. Only militaries and criminal terrorists use body armour.
    "...real benefit to 5.7x28 or 4.6x30..." Same as 5.56/.223. A troopie can carry a whole lot more of either.
    "...not adding a new caliber to supply chains..." One comes in, another is abandoned.
     
  10. grampajack

    grampajack AR Junkie

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    Actually an increasing number of career criminals are wearing body armor now.
     
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  11. Ryanxia

    Ryanxia Member

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    That would be your Canadian mindset :) A lot of people own body armor, it's a lot safer to throw a vest on and grab your rifle to go clear your house in the middle of the night than to go without it. And like you said, militaries use body armor, so for those who like to be prepared for the extremely unlikely event of defending one's self & community from a military host, AP rounds are a factor in defense planning for a lot of people in the U.S.
     
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  12. bnolsen

    bnolsen Member

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    If the p90 ammo wasn't so damn expensive it would be a great weapon for weight, sheer amount of ammo and recoil control. In videos they look VERY controllable when fired in short bursts. As an SBR it would be a good home defense gun for family use (yes that includes kiddos)....those lame sbr laws...
     
    Last edited: Nov 22, 2017
  13. Ryanxia

    Ryanxia Member

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    SBR is just an extra $200. Sucks but not really a hurdle.
     
  14. jmorris

    jmorris Member

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    I think the point is to make money selling things. Also folks that have one of everything can still have something to buy.

    I have ran a P90 and they are a fun bullet hose, not the first gun I would grab but not the last either.
     
  15. Girodin

    Girodin Member

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    You might have been able to call it a fad 15 or more years ago. Even when the PDW concept was being developed/pushed and there were more users adopting them I don't know that it really ever amounted to a fad, defined as "an intense and widely shared enthusiasm for something, especially one that is short-lived and without basis in the object's qualities; a craze." They were never particularly widely adopted (and arguable were not really meant to be.) Rather, they were a niche weapon designed for a particular role. In terms of evaluating them I think people fail to make the correct comparisons. First I think it requires parsing out what end user we are talking about, mil, LE or private. I think one needs to carefully consider the role it is going to fill and then make the comparison to a pistol, a sub gun and an assault rifle (or the civilian versions of the last two if we are talking civilians in the US).

    Look at what the design was supposed to accomplish. Only one advantage they were seeking was defeating armor. The PDW was supposed to offer an increase in range and accuracy over sub guns as well. I can only really speak from personal experience about the PS90. I've never even handled an MP7 let alone used one enough to have a base of knowledge to allow me to comment intelligently. I'm relying on other information out there from other sources on that one. With that disclaimer I would say the PDW class weapons offer an advantage over sub machine guns in terms of bother accuracy and range. I can get reliable first round hits at much greater distance with a PS90 than I can my Uzi. Even when making a more apples to apples comparison and using a sub gun with a RDS the PS90's exterior ballistics offer an advantage at ranges over 100 yards. Get a target, get a PS90, get a sub gun of your choice and do a walk back challenge. If I were trying to get hits at 200 yds the trajectory of the PS90 offers a notable advantage vis-a-vis a 9x19 subgun. Take a look at some ballistics tables for each round. The PS90 is also a more precise weapon than 9x19 sub guns. I can't speak to the MP7. As to whether an AP 9x19 round would do as well defeating armor, I'd be out of my lane commenting on that one.

    The P90/PS90 SBR is 5.7 lbs and roughly 20" long. The MP7 weighs only 4.2 lbs and is approximately 16.5" with the stock collapsed. The Uzi 7.5 lbs and 18.5 with the stock collapsed. There are many MP5 variants but an A3 weighs 6.8 lbs and is about 22" with the stock collapsed. Even the modern Kriss is 6 lbs and 16" with a folding stock.

    Magazines of roughly the same size as 30-32 round mags for the MP5 and Uzi hold more ammo. 40-50 rounds for the MP7 and P90 respectively. If you are designing something for a user who is unlikely to be carrying many spare magazines that is an advantage. It might be less significant for other roles where the user would be expected to be carrying more magazines.

    For what it is worth, full auto I believe the P90 to be more controllable than an Uzi and some other sub guns I've shot. I'd need to shoot it side by side with the MP5 before I said too much about that but my hypothesis going in would be that the P90 would be more controllable.

    As to supply chain, I'd be out of my lane speaking to LE or Mil users but I wonder how much difference there is sourcing a cartridge of a different chambering versus a completely different cartridge in the same chambering.

    Also as addressed supra in this thread, SS109 can be obtained by civilians in the US, AP 9x19 not so much. Also the SS109 rounds might not be the most desirable depending on use.
     
    Last edited: Nov 27, 2017
  16. Girodin

    Girodin Member

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    I would largely agree with the above. As an owner of a PS90 I would not pick it over an AR for defensive use. Terminal ballistics alone are a night and day difference and very significant factor as far as I am concerned.

    Likelihood of prolonged firefights aside, once can put a 60 round magpul D60 in an AR and a 21 round mag in glock and now you have 81 rounds with no spare mags (assuming no +1s for either). Thus that argument would actually point in favor of the AR. I didn't consider surefire quad mags or 100 rd mags because I don't view them as reliable enough and or practical for HD.

    An AR chambered in 5.56 is also a .22 caliber. With proper load choice it also offers less over penetration risks than pistol caliber cartridges. As compared to the 5.7x28 I don't see one having an advantage that would tip the scales on that consideration.

    I agree the ring sight is less than ideal. My biggest issue with it was that it would wash out. Sticking a RDS on the railed version does put the optic higher than I like, however, there are low mounts available that address that issue.

    I'd agree with this conclusion. This isn't just a theoretical choice for me. I have both. The AR gets the nod. I have no emotional investment in either. I look it simply as what is a better tool for the job. For HD the AR is IMHO objectively better for me. I have shot animals and seen animals shot by each. Anecdotally there seemed to be a pretty noticeable difference in the performance of each. About the only argument I could make for the PS90 would be that it is MUCH less blasty. Many new shooters seems to affected by the noise and blast more than the recoil. Shooting the PS90 is like shooting a 22. I believe a gun one can get hits with confidently is MUCH better than one a person cannot use confidently. That said with a suppressor the otherwise blasty 5.56 SBR is tamed to the point that it too seems to not really affect newer shooters. I can think of worse choices than the PS90, and I'd make the most of it if that was all I had, but I wouldn't pick it over my ARs (and a handful of other weapons) given the choice.

    This is the long and short of it (although we could quibble about 5.56 not really being "full power" out of shorter barrels). Its my belief that this one major reason why the PDW largely hasn't taken over the role of the sub machine gun. The short barreled AR has supplanted it instead and for good reason.
     
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