The New York Post comments on the military’s XM25, a new 25mm grenade launcher that will launch smart grenades. I have no doubt this is a neat, albeit expensive toy, but I think the hype is a bit nauseating. Let’s take a look at the Post’s coverage:
The XM25 Counter Defilade Target Engagement System is a rifle that can fire through doors and walls, leaving the enemy no place to hide, FoxNews.com said.
That’s funny, I’m pretty sure my shotgun loaded with 00 buck has no trouble with doors and walls either. In fact, I’d bet my Glock will shoot through doors and walls too.
It has a range of roughly 2,300 feet making it possible to fire at targets well past the range of the rifles that most soldiers carry today.
The designated marksman’s M14 will reach out that far, and I’d hate to think of how much recoil this has if it can lob a 25mm grenade an entire kilometer. Actual spec says it’ll launch 500m to a point, and 1000 m for an area burst. I’m skeptical it’s practical range is actually that far. If it is, I’d hate to be the soldier who has to shoot something that thumps that bad all day.
My guess is the Army is selling this to taxpayers as the greatest thing since sliced bread so they don’t balk at the 35,000 dollar price tag for each unit. If it’s really as good as they say it is, It’s worth it. But I’m skeptical. The grenade uses the number of rotations to estimate distance. I would think that could be altered by atmospheric variability. Some folks around here are pretty good with ballistics. What do you think about using number of rotations for a distance measurement? What would be the variability, assuming you knew the rifling twist? It could be it’s actually a pretty good proxy for distance.
I have to admit, the biggest thing that makes me skeptical is that it’s built by H&K :)
I would be shocked to learn that these rifles lacked a high altitude setting.
This is far from new.
But while a PIA way to do it I think revolutions would work fine, I can’t see atmospherics effecting rotation, but could effect speed. I can’t see where this would be a bad way, just like I said a PIA, means batteries, a sensor, etc. Time is easier to do, but could be affected by other factors.
The number of rotations is a factor of twist over time. Distance will vary due to muzzle exit velocity. Most ballistic programs use the BC of the projectile and current Baro pressure and temp to approximate friction losses due to air density, but this can be standardized for a known load (hence, BDC reticles on scopes). It isn’t as difficult as you would guess at first blush. Alternatively, the gunners could just bring their iPhone or iTouch out with them…as they say: “There is an App for that”
Yeah, I remember this. An ex-marine told me about this when I used to work with him at a temp job. Said it was and I quote a “chunk of shit”. Not for the reasons you specify but he said that the feilds test results are exaggerated and the pricetag is simply not worth it.
If you were a real operator, it would work for you no matter what the altitude was.
You suck, and we hate you,
(Signed)
H&K Marketing Department
http://larrycorreia.wordpress.com/2007/10/09/hk-because-you-suck-and-we-hate-you/
Actually the fuze is quite reliable and boatloads more accurate than mechanical time fuzes of a generation ago. Counting turns is easier than making a clock accurate enough to place the projectile within 5 meters or so.
This technology should prove quite useful. Biggest drawback I see is just when this gets fielded, we will still have smoothbore tank guns. I’d much prefer a 50 meter bursting area over 5.
Wikipedia has the effective ranges as 500 m point, 1000 m area – which I find more believable.
The South Koreans are issuing a similar 20mm launcher connected to a rifle – a concept the U.S. Army gave up on – with the Daewoo K11.
I hope we are issuing these new grenadiers flechette rounds so the have some method of personal protection.
“I hope we are issuing these new grenadiers flechette rounds so the have some method of personal protection.”
The training rounds are slugs, so they’ll at least have a deer-slug option. They won’t be using the XM25 as a their only weapon anyway though. Current fielding strategy is an arms room concept so they’ll pack it in addition to other stuff when they think they need it. The XM25 guy will also carry an M4, but he probably won’t need a M203/320.
Oh and the reason these things are so expensive is that they’re all one-off prototypes at this point. They might be out of a single digit production number of articles now, but it’d be close.
“The XM25 guy will also carry an M4”
I thought they were dedicated to just that weapon. It’s 14 lbs and I bet a load of grenades gets heavy fast when you are humping mountains and wearing body armor.
“I thought they were dedicated to just that weapon. It’s 14 lbs and I bet a load of grenades gets heavy fast when you are humping mountains and wearing body armor.”
I’ve never seen anyone suggest that. And yes it will be heavy but so is a 203 or 320 with a load of 40mm grenades. If they think it will be too heavy, then they won’t take it. Again, it’s not a standard issue item they have to carry. It’s something the unit can take when they think they’ll need the equivalent to short ranged artillery.
What’s wrong with smoothbore tank guns? Rotation disrupts the jet of a shaped charge and is obviously not a good idea for a fin stabilized dart. Back when we fielded the first generation M1 tank with the old 105mm rifled canon we had to put slip rings around the rounds (which may have predated the M1, I’m going off my memory of the fantastic book _King of the Killing Zone_, which is highly recommended for engineers and the like in general, as it tells all about how the tank was designed and developed, the trade off process (which included an archetypal Chrysler car executive who insisted it look good … often to the benefit of what really counted), etc. etc. Also debunks all the initial unfounded propaganda about it.).
I also suspect rifling is not good for the newish beehive round (i.e. using it as a shotgun).
They can also get higher velocity with the smoothbore main guns. And I think you’re right, when the first started using the fin-stabilized discarding-sabot penetrators, they put in the ‘slip’ fittings as rotation caused problems with them; thus smoothbore guns.
The early model M-1 Abrams had the same M68 105mm rifled cannon as the previous M-60 Pattons, which was a made in America copy of the British L7 tank gun. The M1A1 upgraded to the M256 120mm smoothbore in the mid-to-late ’80s, IIRC. Until the very latest model Challenger 2s, the Brits stuck with a rifled 120mm for their current tanks.