Does a UMP-45 have any advantage over a 300 Whisper M4?


July 15, 2009, 10:41 PM
From what I have read the 300 Whisper out-performs all pistol caliber subguns, and it only requires a new upper on an AR (it even uses .223 mags).

Does the H&K UMP-45 have any advantage over a 300 Whisper (other than cheaper and more available ammo)?

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July 15, 2009, 10:59 PM
Not really, although I only have a HK USC which uses the really expensive 10 round mags. I think you can get a .300 Whisper upper for about 1/2 or less of what a USC with UMP conversion will run, that pays for a lot of ammo.

Jeff White
July 15, 2009, 11:54 PM
Pistol caliber submachine guns have been pretty much replaced by short select fire rifles chambered in an intermediate cartridge. The only reason anyone uses a submachine gun anymore is for highly specialized tasks, usually involving suppressing the weapon and keeping it in a very compact package.

July 16, 2009, 06:29 AM
It does appear that most LE Agencies have dumped their MP/UMPs for M4s, and that a SMG is only useful if you could take advantage of all its capabilities (full auto w/ a supressor). Even then a .300 Whisper can do everything a UMP does and more.

I thought a UMP conversion would be a colectors item besides being fun to shoot, but spending $1,600 for a USC + $1,000 for a conversion + $65 for mags seems more that it's worth.

July 16, 2009, 08:45 AM
it would be a lot easier to get ammo for the .45.

July 16, 2009, 09:46 PM
The cheaper .45 ammo is definitely a +, but the 300 Whisper offers more options with different bullet weights and velocities.

Would anyone chose a supressed UMP-45 over a supressed 16" .300 Whisper AR?
(for a SHTF gun).

July 17, 2009, 08:47 AM
depends on how deep I could stack the .300 whisper ammo, and what you mean by SHTF

July 17, 2009, 09:09 AM
SHTF: If you were a lone officer arriving on the scene of an active shooter incident at a school w/ 2 suspects armed with shotguns + pistols, would you rather have:

1) A 16" .300 Whisper AR w/ supressor + 200 grain subsonic JHPs.


2) A UMP-45 w/ supressor + 230 grain JHPs.

(Similar optics on both guns, either Aimpoint or Eotech, similar number of mags).

July 17, 2009, 09:39 AM
I've never held an AR in 300 whisper, but I have used a UMP-40 rather extensively.

The UMP is very small when folded and lightweight. Other than being a bullet hose in very tight quarters, it's meh. I wouldn't use one outdoors.

July 17, 2009, 09:59 AM
Is your PD going to allow you to use reloaded ammunition?
Is your PD going to allow youto use ammunition you supplied yourself?

Is your PD going to pay the premium for the oddball cartidge?
IS your PD's legal counsel going to be happy with you using a non standard, in fact rare, cartridge?

Badger Arms
July 17, 2009, 10:18 AM
When the SHTF, the bad guys might be further than 100 yards and be wearing armor. I'd opt for the skinny bullet instead of the fat bullet any day of the week. But, then again, if you can find ammo for it, why not use what you have got? Run out of 300 Whisper and you're SOL. Run out of 45 and there's likely to be some available somewhere near.

July 17, 2009, 11:34 AM
I agree that the UMP-45 is most effective using burst/full auto with a supressor. Outdoors in semi w/o a supressor you're better off with an AR.

My question is not whether a PD would allow an officer to use a particular round, just which weapon would be more effective.

The nice thing about the 300 Whisper is that you can fire subsonic rounds with a supressor, and still fire 125 grain supersonic rounds if necessary.

A subsonic .223 round would be worthless, while an AR firing supersonic rounds w/ a supressor would still be loud. The 300 Whisper seems to fill a gap between a SMG and an AR. BTW, both sub and supersonic 300 Whisper factory ammo is available on Midway.

Noticing the current trends it appears that the .223 is the end-all for tactical teams. MP-5s and UMPs have gone by the wayside, and the 6.5/6.8 are losing traction due to the ammo crisis and the Army's decision to stay with the 5.56.

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