There are two HE warheads for US 2.75in 70mm FFAR family, 10pdr M151 and 17pdr M229. My question is: how widespread is the use of "17-pounder"? Does the USA use it? Any other users in the world? does someone know?

I don't think they were even manufactured.

They were most definitely manufactured...and used. We had both available for our gunships in my first campaign.

http://www.vhpamuseum.org/weapons/images/10LBAND17LBERS.jpg

http://www.vhpamuseum.org/weapons/images/Rockets.jpg

"Rockets in storage bunker. It is very easy to distinguish the 10 lbs. from the 17 lbs. warheads. All of these rockets are point detonated high explosive rockets. As the UH-1B/C gunships had a crew chief and a gunner to protect the tail, the helicopters flew at very low levels or NOE (Nap of Earth). The rockets with a proximity fuse for detonation were not effective at these altitudes as they would detonate as soon as they armed unless the helicopter would "pop up" to shoot at a higher angle."-George Quackenbush

AIUI,
greater diameter seems to be necessary for greater penetration (females might argue... ),
thus we have the 7" diameter Hellfire family with its rather beefier 20-28 pound warheads (20pounds in the first models, with a metal-augmented 28pounds in some later variants) for those hefty targets like bunkers and MBTs,
which seems to be the preferred killer for arming an abundance of helicopters and UAVs.

But for general purpose destruction of everything from technicals and sedans to the occasional mud huts, would this larger 70mm warhead be more preferrable over the lesser?
(is it the actual weight/volume of explosive that decides the damage, or does it need to be a larger diameter, rather than longer length, to do more overall destruction?)
Or in this day and age of reduced collateral damage, is the 10-pound warhead family adequate (there's that word again) enough?

There's this interesting link to the Brazilians' AVIBRAS Skyfire 70 series (3.8 & 6kg warheads), suggesting they've developed 70mm rockets, warheads, and motors as an artform, almost.
It was mentioned in another thread that the Canadian CRV-7 family was quite impressive as well (highest velocity 7cm rocket?).

With the interest today in these precision guidance developments, that 70% larger warheads seems still quite useful without the expense and bulk of the Hellfire series, especially if precision kits can adapt to it suitably enough...

I'm thinking poorman's laser-seeking NetFires (designated by small UAVs) with surface-to-surface ranges to 12km, outpacing the 10km as suggested by the Designation-Systems.Net's entry on the Hydra 70 with the US Mk66 motor,
though I anticipate that medium-altitude release from a UAV might offer extended (glide-out or semi-ballistic?) ranges with either, should the need arise...
A nice few charts on Wiki's entry give a good breakdown of which warheads with which fuzes.

Would a pair of 7-tubed 70mm launchers with the 17pound warheads (assuming precision-guided models) actually be a more favorable payload than a triplet of Hellfires?

One of reasons I asked was that I would think the 17pdr or similar "heavy HE" warhead might be useful in various mudhuttistans, given the trouble mud huts are giving to light weapons. Why not even transform say HMMWV AT units to light rocket artillery using these rockets for direct support?

From articles dating as far back as the 1980s, there were discussions of arming LAVs (8x8 Piranhas) with various weapons, one of which included a rather odd layout of 80mm Oerlikon/SURA rocket tubes (they looked like a pair of (semi-circular?) 19-or-so round pods that merged somewhere in the middle and shared several tubes between them, so not exactly a full ~38 were actually there).

In all my digging, the 80mm SURA family seems to be even harder in finding info about than the 68mm SNEBs...

A smart @ss like me would almost say, "let's bring back those T34 Calliopes like Shermans had",... several dozen 4.5" rockets (precision guided, mind you) at the ready would do wonders for your own troops' morale, and scare the bejesus out the adversaries when it shows up and starts shooting...

Some sorta big-honkin-box-launcher on those ATGM Strykers, in place of the twin TOW pod, with a set of reloads in the hull, could effectively carry more ready rounds than the Stryker MGS (105mm gun), with a full set of reloads internally.
Sounds like a winner.

Spent the last 20minutes trying to find pics of said LAV/Piranha with the 80mm rocket pods, but it was a no-go...
Still, even a pair of 19-round 7cm pods, with the 17pound warheads (providing we can precision-equip them) certainly seems like it has potential, at least in theory.
Possibly in a high-angle capable mounting, with a centrally-mounted retectable telescopic mast with long range optics and designator, could be used to fire from all sorts of secure positions, at targets several km away.
Trick is, we have to make the system look more favorable than using SP mortars and light artillery pieces....
A humvee should easily carry a 4-7round launcher with minimal modification (think TOW-armed scouts), but a purpose-designed system could mount a rear turret with numerous pod configurations,
in short, a miniaturized version of Canada's MMEV Multi Mission Effects Vehicle, seen here at Wiki and here at CASR.

By the way it seems Turks have developped a light towed 70mm rocket launcher. Among other toys.

http://s188567700.online.de/CMS/index.php?...0&Itemid=47
And I also recall seeing some ADATS modernisation that allowed for either ADATS tubular containers or replacing of aech of them with a 7-round 70mm pod with PG rockets.

Interesting idea - especially as they now have laser guided 70mm rockets available. I could see many, many uses for these.



-K

Or go navy...

Back in the 1980s Breda manufactured a naval mount with 20 105mm rocket tubes that weighed in at 1.72 tonnes. Yes, fairly heavy, but gives some idea of the capabilitities. Was mainly intended for smoke / chaff / decoys, but could also fire HE out to 12km. I have also a photo in a book of a mounting on a Lupo class, with 10 105mm and 32 51mm rocket tubes, the 51mm being for assault purposes only. The 32 51mm tubes taking up the equivalent space as the 10 105mm tubes.

These mounts are of course not armoured

Interesting note from TM 43-0001-30 (Aircraft Rockets) which can be Googled:

When firing rockets with the M229 warhead and MK66 Motor from the A/MH6 and U/MH60 Aircraft, limit engagement of targets
and ensure line of fire is clear of obstructions at a minimum distance of 450 feet if forward airspeed exceeds 10 knots or 350 feet if forward
airspeed is less than 10 knots.

NOTE

Rocket, HE, 2.75-Inch with warhead M229 and Motor MK66 is airworthiness certified for the A/MH6 and U/MH60 Aircraft only, and will
not be issued to units that do not use these aircraft.