[SidPost]

What quality options exist TODAY in an MP-5 in the .40/10mm caliber? I have mixed feelings in the 40S&W versus 10mm caliber because the 10mm firearms seem to be extremely rare and very expensive and the 40&W would be more common with a side arm (P-30) though I have CCW'ed a Glock 20 for years. It appears that a lot of the component parts are the same for both so, long term support seems to be the same for both calibers.

HKParts.net has the Vector 40S&W for ~$2800 and it looks like a parts kit plus Dakota Tactical conversion would be ~$3700. Both look like they would need some conversion parts to go from a pistol to an SBR status. The former sear hosts I have seen seem run over $4K so, I don't see a good option there.

What sort of money would I be looking at and what options do I have with a 10mm MP-5/SBR? Where I travel and shoot is more open and rural so, having the option of more "reach" with a 10mm is attractive but, I'm not sure how much thump I would loose at longer ranges. What would I give up with a 40S&W out of an SBR versus a 10mm at ~100 yards?

 

[bordercop]

MP5-10 also uses two different locking pieces, (or was it rollers) depending on the ammunition load being used (low impuls vs high impulse). I think you'll have a harder time finding the 10mm parts.

In a 4" test barrel, the difference between 200 grain bullets is 1300fps vs 1050fps.
If you're concerned with having range, using the longer barrel rather than the "k" length, shouldn't be a problem with either cartridge.

I'd go with .40 myself, simply for the sake of simplicity. If I was concerned that it didnt' have the reach, I'd look into something with a rifle cartridge before considering the 10mm. That's just me, though. I prefer to stick with more mainstream cartridges.

 

[Chopstix Kid]

The $3700 DT guns are LSC fused magwell conversion. HKParts.net has 20 D54P/40's in queue that will be build on SW flats (I will roll them) with German parts kits. I do not know the price yet as I will have to make one first to see how much work is involved with the SW flat.

The MP5/40 and MP5/10 share 3 different LP's, #24, #25, #26. Bordercop is correct in that the 10 uses primarily only one of them due to the hotter 10mm round while the .40 is more ammo specific. I have seen 10's with the LO-impulse (#24) but those guns typically have had roller marks. In my postie-10, I use a HI-impulse (#25) and it chews through everything I have fed it so far.

 

[bordercop]

I have seen 10's with the LO-impulse (#24) but those guns typically have had roller marks.

FBI used a reduced velocity 10mm round designed just for them, prior to the development of the .40SW round. It was pretty much the basis for the .40SW cartrige's specs. These would have had the low impulse parts, but shouldn't use the full powered 10mm cartridges.

 

[SidPost]

If I was concerned that it didnt' have the reach, I'd look into something with a rifle cartridge before considering the 10mm. That's just me, though. I prefer to stick with more mainstream cartridges.

I've got an SBR AR-15 and M-16 but, I'm looking for something more compact. Putting a 300 AAC Blackout into a backpack is doable but, I really want to get rid of the buffer tube length.

 

[SidPost]

The $3700 DT guns are LSC fused magwell conversion. HKParts.net has 20 D54P/40's in queue that will be build on SW flats (I will roll them) with German parts kits.

What's the difference in the LSC fused magwell versus the SW flat? Does one use the German magwell and the other come prestamped correctly?

 

[bordercop]

I've got an SBR AR-15 and M-16 but, I'm looking for something more compact. Putting a 300 AAC Blackout into a backpack is doable but, I really want to get rid of the buffer tube length.

G36k? Just a thought.

 

[JTinIN]

HK53 .....

 

[jcabbbang]

There are also a few .357 sig MP5's out there. I have one that I purchased from Vector years ago that was a SBR. Was not happy with the internals or the barrel, and immediately replaced the internals with German parts. It is very reliable and fun to shoot. I recently hunted down and purchased a Urbach .357 sig navy barrel. Just got it back from RDTS, where Ralph rebarreled it with an Urbach barrel. RDTS did a great job and was fast on turn around. I like this round real well and it works out great in an MP5. Have a suppresor on order for it.
You might consider something in this round if you can find one. Chris

 

[4C Dragon]

I have them all, but my favorite is a HK MP5K 357 Sig that TPM built recently. It is built from a SP89 and uses standard 9mm mags. He used a Urbach K Navy barrel and a modified 53 recoil spring. TPM does great work, welds are some of the best and his wait time is weeks, not years like another smith mentioned.

 

[scottinthegrove]

After reading this thread, I'm not sure that I understand what the question is. The OP asked specifically:

What quality options exist TODAY in an MP-5 in the .40/10mm caliber?

What sort of money would I be looking at and what options do I have with a 10mm MP-5/SBR? Where I travel and shoot is more open and rural so, having the option of more "reach" with a 10mm is attractive but, I'm not sure how much thump I would loose at loner ranges. What would I give up with a 40S&W out of an SBR versus a 10mm at ~100 yards?

But then went on to other caliber options:

I've got an SBR AR-15 and M-16 but, I'm looking for something more compact. Putting a 300 AAC Blackout into a backpack is doable but, I really want to get rid of the buffer tube length.

To me strictly speaking to .40 S&W vs 10mm, 10mm is so much more a custom build. With that comes custom prices. My understanding is that the only difference between a MP5-40 and MP5-10 is the depth of the chamber and the locking piece. A factory MP5-10 barrel will not be cheap. So price verses performance, I'd think a .40 S&W build would be a heck of a lot less money for a slightly diminished terminal ballistics. Personally if portability is a big concern given the caliber restriction of .40 S&W or 10mm, I'd go with a .40 S&W reverse stretch. That would be a "K" length barrel on a full size receiver. So use of a standard A3 stock would be an option. With a pistol caliber you wouldn't be loosing a lot with the 5.5" barrel compared to the 8.85" barrel of a standard MP5-40.

As far as other caliber options, to me the best would be a PTR 7.62X39 PDW. Much better knock down from the short barrel, and it would be an off the shelf item. CDNN had the pistol version for around $1,000.00. It would not have any 922(R) issues and almost as small as the MP5-40/10.

All of these short barreled options would be fine in bright day light. If you would need the option to shoot in low light, I'd stay away from short rifle caliber carbines. After firing the first round, the fireball of the rifle powder burning outside the barrel would blind you for several seconds. Good luck with your backpack carbine project.

Scott

 

[Clicker]

Here's my 2 cents........it comes down to a couple of things when deciding between a 40S&W and the 10mm.
Do you plan to shoot it often and is ammo cost a concern? If you answer yes to both then the 40S&W clearly wins. If you don't hit the range blasting thru 200 rds every weekend then the cost of 10mm ammo might not be a major factor in the debate.

Do you reload? If so then go 10mm as the cost difference really comes down to brass. While the 40S&W brass is littering the ground at my range you'll never find any 10mm for the taking.

I also cast my bullets so reloading for the 10mm is cheap and rewarding, outside of the brass supply. I take extra steps to control my brass loss at the range.

I'm not a fan of the "K" builds for the 10mm due to velocity losses with the shorter barrel. 1500FPS is easily attained with 180 grain bullets in the FS guns.

The biggest issue I've encountered while planning my 10mm custom build is the availability of HK or good aftermarket barrels - there are none! You could rechamber a 40S&W barrel to 10mm but nobody will extend the flutes. I have a beautiful saw cut HK MP5/40 receiver frontend to graft onto a LSC flat so I'll probably wind up buying a Special Weapons barrel and using it until a better option surfaces. This plan puts my build cost under/near $3000.00, good luck with yours.

 

[SidPost]

After reading this thread, I'm not sure that I understand what the question is. The OP asked specifically:

But then went on to other caliber options:
Scott

My SBR rifle caliber options are ~27 inches long WITHOUT a suppressor. Muzzle blast from NATO spec ammunition from an SBR is horrendous IMHO. In low light it may not be a FLASHBANG but, it's still hard on my ears and eyes WITH protection. If I'm not on a square one-way range for target practice with all my gear, I'm not sure a pair of foam plugs and eyeglasses are adequate protection for my ears and eyes.

A 300 Whisper/Blackout subsonic round might be an opton but, a .40/10mm round's larger diameter is attractive. Getting low flash LE ammo for night shoots is relatively easy. Ballistic compromises from a short barrel are less with a pistol round and supersonic/subsonic rounds are something that can purchased relatively easy. I do reload but, I prefer to spend my time on the range, not at the loading bench.

A true SMG platform or PDW is going to be more compact and easier to tote in a backpack. By backpack, I mean something that looks like a book bag or something for a city park or shopping mall, not a larger bulkier military style or hardcore hiking/camping model. I like Uzi's but, they are heavy and bulky. An MP-5 is just a better platform in the SMG/PDW role based on my experience so pairing one with my pistol seems like a natural and relatively obvious choice.