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Subject: Ideal Gun Caliber for 21st century
earlm    6/1/2010 9:29:06 PM
If a vessel can have one gun only which caliber is preferable? It seems the guns are used to spray the upperworks of opponents with time or proximity fused ammo rather than to hole the hull. Looking at it that way is it best to have a 155mm for shore work and 57mm for all else. How does a 3 inch compare to the 57mm?
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doggtag       6/2/2010 7:35:38 AM
(sigh) These are the kinds of debates I wish I had more time to take part in....
On the 57mm (Bofors gun license-produced by UDLP BAE)...
It has been sggested that, at 220rpm max rate of fire, the 57mm will put more weight of shell (~ 6pounds) on target than the Italian 76mm (also license-produced by UDLP BAE), whose rate of fire has been suggested between 85rpm for the US mounts (FFG7/Perry class frigates, etc), to 120rpm for the Super Rapide mount (used by other nations, esp. on corvette-sized and other FACs).
Ranges are similar, with the 57mm HCER High Capacity (more HE filler and better fragmentation) Extended Range shells having a maximum range (although accuracy is not mentioned) of ~17km,
and the 76mm gun having a range of ~16km, with an extended range, improved performance ammo reaching 20km ( I can't verify the US uses either extended range rounds...)
Points can go to the 76mm because of the OTO Melara/Breda development of the Davide system DART guided subcaliber projectile,
but back in the late 1980s-mid 1990s, UDLP (prior to BAE acquisition) was working on a guided 60mm projectile for future CIWS consideration....
The latest ATK (Bushmaster guns) developments for C-RAM systems (land-based CIWS) has development focused around a 50mm guided projectile...
So it certainly seems feasible that the technology could/would/should cross over to utilize the now-preferred 57mm gun system.
Query EAPS (Extended Area Protection System), especially over at the DTIC.Mil's website the past few years of armament symposiums, for more info on various guided projectile developments down thru even 40mm caliber (which has actually been proven capable as far back as the mid 1980s, between Ford Aerospace and Vought Aircraft designs, with the idea it would cross over into a subcaliber anti-helicopter round for the Abrams' main gun, possibly).
Sorry I can't provide the links at the moment, but I have lots of them on this stuff.
As for the ideal big deck gun size (127mm, 155mm, or other), there's surely more posters here who can contribute to that debate as well...
(I hope so, at least....)
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perfectgeneral2       7/4/2010 6:55:08 AM
I'd hope that the RN switches to 155mm at some point soon as the through life costs seem to be better for a more widely used munition diameter. The extended range doesn't hurt.
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doggtag       7/7/2010 8:01:38 AM
...But one of the biggest differences in shipborne guns, especially in 155mm caliber,
is that ships prefer fully assembled ammunition (projectile seated into case containing propellant),
whereas land-based artillery more readily use separate loading ammo,
because land-based artillery quite often does not fire to maximum range and an economy is had,
both in propellant costs and barrel life,
when a maximum charge of propellant isn't required.
Ships, especially today with mostly fully automatic ammunition handling,
prefer the complete ammo (projectile + propellant) as that maintains a more consistent, sustainable rate of fire (for various reasons, although argument could be made as to just how high a rate of fire of however-heavy shells do we really need?).
There used to be the argument made for the 155mm AGS system for the USN's DDG1000/Zumwalt class "destroyers" that it could fire standard artillery shells like land-based systems, in addition to uniquely-AGS guided projectiles (LRLAP's), but over time, the complexities involved with being able to handle both the massively long (~5 feet or so) LRLAPs as well as separate-loading typical 155mm artillery shells and charges,
was perhaps seen as a too-complex not-necessary-to-have solution looking for a problem,
and now the AGS is LRLAP-specific.
Questions as to the merits of 155mm ship guns other than the AGS,
the Germans trialled the MONARC system, the turret of the PzH2000 and its 155/52 gun system, in addition to below-decks handling equipment,
and there were British trials with the AS90's 155/39 gun systems mounted within the confines of a 4.5" naval gun turret,
but in both cases,
separate-loading ammunition was still used,
and as these were trials systems only,
there were many components of the land-based equipment that wouldn't stand up to a lengthy lifespan at sea in a high moisture saltwater environment...
As PGM development continues, it's probably going to be seen that 127mm-sized guns are at the maximum desireable size for ships, to have any measurable number of shells available, that are cost-competitive versus just using a large number of guided missiles instead.
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C2       7/7/2010 12:13:24 PM
Does anyone know why the USN doesn't just use a small calibre VLS in place of a gun? If there were a way too stack such a system it could potentially have a greater capacity, range and hitting power than a conventional 155mm, and be more practical than existing low calibre systems.

Say Hellfire(3) weight,dimensions and range + plus booster; lock on after launch with initial telemetry provided via ship to missile link.  
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Hamilcar       7/7/2010 12:36:30 PM

Does anyone know why the USN doesn't just use a small calibre VLS in place of a gun? If there were a way too stack such a system it could potentially have a greater capacity, range and hitting power than a conventional 155mm, and be more practical than existing low calibre systems.

Say Hellfire(3) weight,dimensions and range + plus booster; lock on after launch with initial telemetry provided via ship to missile link.  

1. Flopover.
2. A gun is KISS applied to a slow target.
3. Missiles like Hellfire are EXPENSIVE in cost, maintenance, and volume to the naval target set intended defined.
4. At that range more shots from a 2010 gun-fired 3P prox fuse for less dollars with similar PK.   
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JFKY    Spoil Sport.....(Herald)   7/7/2010 12:59:09 PM
1) there is no "ideal" caliber...for what purpose, AAW, ASuW, Gunfire Support?
2) What about "Metal Storm" as a last ditch CIWS, high rate of fire, in 12.7mm, 20mm, or even 40mm HE?  IS there a technical draw back to Metal Storm, i.e., it doesn't work?  Or a technical draw back in the cassette reload idea?  Or is it such a small caliber weapon that missile ballistic carry thru reneders it pointless?
Just ask'n and throwing it out there...I'm not committed to idea, so there will be no Blue Apple/Wings defense of the idea.
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doggtag    Actually....   7/7/2010 1:22:03 PM

Does anyone know why the USN doesn't just use a small calibre VLS in place of a gun? If there were a way too stack such a system it could potentially have a greater capacity, range and hitting power than a conventional 155mm, and be more practical than existing low calibre systems.

Say Hellfire(3) weight,dimensions and range + plus booster; lock on after launch with initial telemetry provided via ship to missile link. just described the NetFires/NLOS-LS (Non-Line-Of-Sight Launch System)...
But to make a pun off H's post:
1) flop.
Because Netfires, a joint venture between the US Army and US Navy, would've been that Hellfire-sized, "small caliber" VLS system, offering range equal to or better than any 155mm gun system (at least, better in range than any US-operated 155mm gun system, that is.
But it's a flop, because it became too expensive and too underperforming, so the Army bailed on it,
leaving it in the USN's hands to solely fund.
But they've since voiced their concern over costs and performance (or lack thereof, there have been issues of the seeker head not being successful enough in testing),
and NetFires' future looks now like it's relegated to the Davy Jones' locker of promising,
but perhaps overly ambitious and therefor doomed to failure/cancellation,
weapons systems that coulda, woulda, shoulda, mighta,
but  in the end, didn't.
(and do feel free to browse the Wiki links/references at the bottom of the article...)
A close contender, but will still need considerably more money to develop it for ship use (configured into a Surface Warfare Mission Module for the LCS Littoral Combat Ship).
(Further web searches of "IAI Jumper missile" will yield more results...)
There are several ongoing developments underway to add precision guidance systems
to various surface attack rockets (70-160mm diameter),
a cheaper alternative than making shell guidance systems built to handle the stresses of gun-launched projectiles,
but any of these will still require additional money invested to make the launchers and associated fire control electronics suitable for ship use.
There's also the need for proper sensory integration: how/with what do we use to designate/guide the missiles to their targets?
Are they to be fully autonomous?
Is forward laser designation suitable?
Tele-operated (command guided via video cams in the nose?) with encrypted RF data links?
And as was pointed out about a gun generally being able to point in the general direction of its targets:
do we want a VLS missile system that must do the tip-over at its launch boost apex to attack a target?
That might cost precious seconds to align the weapon with the target as it transits from vertical to horizontal flight.
Or do we make a trainable launcher, like a gun turret, that wecan point in the direction of the target, on a suitable elevation, so locking onto the target is quicker?
(do we waste seconds in the VLS tip over, or waste seconds in traversing/elevating a mechanical launcher system?)
There's probably a debate to be had also as to, do VLS missiles waste more propellant in accelerating to flight status than missiles fired mostly horizontally...?
There's pluses and minuses to each system. It probably then depends more on just what a given customer wants, really.

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Juramentado       7/7/2010 4:03:07 PM
Not to bring this Off-Topic, but the retirement of NetFires coincided with both the Naval Operating Concepts and the Marine Corp Operating Concepts recently released. While LCS lives on for the Navy (per the vision of SECDEF Gates), the Marines basically acknowledged that in fighting for contested littoral access, the current shipboard gun systems (127mm at the largest) would have to be supplemented by aviation strike and "robust land attack missile" solutions from subs and other surface combatants (I read that to mean TLAM).
The question is: is the LCS land-attack mission (using an alternative for NLOS) dead? Hopefully the answer is Yes, as there are other contradictions to the platform designed and the currently published CONOPS that fail to reconcile with the stated mission. But that's fodder for other active threads here and the FBO bid opened in June will produce a short-list that will answer that conclusively.
It can't be said often enough - missiles are sometimes too expensive a solution to deliver major fires when a gun round will suffice. There's the question of minimum stand-off ranges, and you can carry more rounds than missiles.
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WarNerd       7/8/2010 6:28:37 AM

The best naval artillery weapon depends on how you weigh the performance in different roles.

Short range anti-missile work favors the smaller weapons with high slew rates (to engage multiple widely spaced targets) and high rates of fire (for multiple hits). Anti-aircraft and longer range anti-missile engagements against maneuvering targets favors the mid size guns with moderate rates of fire and proximity fused munitions. Bombardment roles are mostly indirect fire and require heavy projectiles for penetration of hard targets. In the anti-personnel role most of the weapons have potential. Anti-ship applications in direct fire are somewhere in between depending on the nature of the target.

Here is a sample of a range of potentially available western weapons and some notes.

                        max.      range   Projectile [kg]       ready                    max. salvo [kg] 
                         ROF    [km]    weight charge       rounds   Usage      Proj.    HE
Goalkeeper     4200       3.3 *    0.36    0.12       1190    anti-missile  428    143
Millennium Gun 1000      4 *      0.55    0.12        200     anti-missile  110      23
Mk.110            200       15        2.4     0.45        120       Dual Use    288    54
Otobreda          120       18.4     6.35     1.15         80      Dual Use    508    92
5 Mk.25, Mod.4 20  23.7 / 98   31.1     3.52         20     Bombard    622    70
AGS /VGAS       10    44 / 180  90       11             20     Bombard    900  110


1. Maximum range for all weapons except the Goalkeeper and Millennium Gun is for indirect fire.

2, ?ready rounds? are the amount of ammunition that can be fired without the gun crew reloading the mount.

3. Weights are for the whole projectile and the explosive content of the HE round.

4. The ?total on target? weights are for a 1 minute of continuous firing or the ready ammunition, whichever is less.

5. The 127mm and 155mm guns have 2 ranges. The first is for conventional ammunition, the second for extended range guided projectiles (still in latest iteration of development) with a heavier propellant charge.

Data is from the Navweaps site

Personnel Opinions

Range is also important for a bombardment weapon because modern warships lack effective armor against same class weapons. This means indirect fire, unless you want to chance an artillery duel, which you could easily lose if the opposition includes a MBT. When fired indirectly impact velocities are limited by the freefall velocity in air for the projectiles. The 30mm and 35mm projectiles will probably lack the energy to penetrate most roofs. The 57mm projectile can probably penetrate unreinforced roofs. The 76mm should penetrate most roofs, but not bunke

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doggtag    see, now this is how discussions here should go...    7/8/2010 9:47:12 AM
a lot of good ideas are being thrown about,
good concensuses (concensi?) are being reached,
and no one has resorted to any personal attacks.
WRT what would be a good gun system for surface fire support,
with the advent of NetFires' demise,
and the obviousness that the 155mm AGS will be DDG1000-specific (meaning: very few in number available to support anything anywhere),
and the fact that, as it sits, the LCS is woefully lacking in the surface effectiveness to fit against perceived adversaries in the littorals (fast attack craft, missile corvettes, shored based artillery and anti ship missile batteries, and shore-launched aircraft (helos and fast movers).
Granted, ideally, a single LCS wouldn't be acting alone were we to be squaring off against a competent opponent.
But were the situation that dire, what do we propose?
My suggestion, on the note of LCS armament,
well it's obviously too light a hull to support any known 5inch gun turrets (the US Mk45 is probably among the lightest).
Certainly, with the tech know-how gleaned from gun development projects such as the lightweight M777 mostly-titanium-allloy-construction 155mm howitzer,
and the lightweight M360 120mm gun tube intended for the now-defunct FCS "light tank" Mounted Combat System,
there is certainly potential there to develop a new 127mm gun system for ships that previously just couldn't handle that bulk (and recoil, as well as a suitably-sized magazine useful for any duration of fire support between resupplies).
But there, we're going to see a lot of time needed, both for the new tube design to mature, and for a new compact turret and ammunition system to be developed alongside it.
Plus, the US still is struggling to effectively produce a fieldable, reliable, 5" gun-fired precision guided round.
A suggested solution I've run up before,
could be had in the following:
XM1156 Precision Guidance Kit.
( from Wiki , little more than a stub article, really )
I don't much about any common sizes for projectile fuze wells (in artillery shell noses),
but PGK is being developed to utilize the exact same PGK fuze to fit into both 105 and 155mm projectiles.
The question is, is it compatible as well with a majority of 127mm naval ammunition?]
If so, that should alleviate the difficulties in engaging stationary land targets with the naval guns.
If not, it may be cost prohibitive to design either a new line of naval ammunition compatible with PGK,
or just as costly to redesign PGK to suit 127mm shells (a stand alone design then, separate from the 105/155 compatible system, if need be).
There again, that solves precision fire support for ships mounting 127mm guns.
But what if you just can't?
The LCS most likely won't, and by sheer budgetary luck, if the USN does get all 55-or-so ships it's asked for,
the current 57mm deck gun is woefully lacking in the surface fire support role, even if the gun can boast a respectable 17km range with its HCER ammunition (although I have no figures of the precision of its unguided ammo at that range.
(see here at NavWeaps for specs on the 57mm...)
Odds are good that the LCS could just as well mount the 76mm/62-cal naval gun also, as this gun was light enough for the USN's Pegasus class missile hydrofoils, and even the Italian Navy's 60-some ton Sparviero class hydrofoils...
But, other than the Strales system's guided DART subcaliber ammunition that's intended more for anti air, anti missile, and within-visual-range anti ship at generally flatter trajectories, the 76mm isn't really configured for any decent precision shore bombardment, even though it can shoot to 20km (read down thru this NavWeaps article for info on the 76mm SAPOMER ammunition)....
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