The M2 Bradley can it be armed with a 20mm gun instead of a 25mm gun?

[silkmonkey]

Looking for information on early variants of the M-2 Bradley being equipped with a 20mm gun instead of the final design version with the 25mm chain gun. Also is it possible to equip the Bradley with this gun and the tow missile launcher system? Also does anyone have a picture of the Bradley Warhammer version of this vehicle with the two tube predator missile launchers?

 

[robunos]

Try these on for size...

http://commons.wikimedia.org/wiki/File:XM723_tank.JPEG

http://commons.wikimedia.org/wiki/File:XM723_tank.JPEGhttp://www.army-guide.com/eng/product3254.html

http://www.armyrecognition.com/forum/viewtopic.php?p=1706&sid=7bfe1f453e58a4256d7025c57b281459


cheers,
Robin.

 

[Sea Skimmer]

Bradley never had a 20mm gun. The XM723 did, but it only served as a developmental basis for Bradley after it and the XM800 had been canceled. Bradley was designed with the 25mm Bushmaster and two man turret from the onset; it also had completely different suspension and a whole lot of other changes.

XM723 was tested with two different 20mm guns. The first was a Hispano-Suiza HS.820 designated as M139 in US Army service and firing a 20x139mm cartridge. It’s very powerful as far as 20mm cannon go, and in fact the 25mm Bushmaster isn’t that much more powerful in raw energy terms. However the HS.820 design was meant for aircraft and didn’t do so well in reliability when used on the ground, and 20mm was too small to work with 70s vintage discarding sabot ammunition. Thus the externally powered Bushmaster with higher caliber neatly solved both problems.

The second 20mm tested on it was called XM236, and appears to have been a revised M139, but I am not certain.
Prior to commencing work on Bushmaster, the US Army also looked at the 25mm KDA cannon, and the 20mm RH202 and fit both to improved M113 variants. The 25mm version became the AIFV, which was exported to Turkey, the Netherlands and a few other places.

The Bradley can easily be adapted to different calibers of guns, going down in caliber would be trivial. But for trials it has been fitted with weapons as heavy as the 50mm version of the Bushmaster III.

 

[Pioneer]

I have to ask why you would be looking at a 20mm weapon in the first place Silkmonkey?

When one looks at the fact that the German's soon come to think that the 20mm cannon on their own pioneering Marder was to light and ineffective, I think the 25mm choice by the U.S Army was one of few good decisions they made! (saying this almost every Western Army can not contain their want of larger and heavy caliber weapons on their IFV/MICV!. Thankfully this has been contained to wet dreams and prototypes!)

Another thing I have always seen a strange is the fact that the U.S Army has 25mm for their Bradley's, whilst its Aviation uses 30mm for their AH-64 Apache helicopters!
Wouldn't it be better from an operational and logistic aspect to standardize this caliber one way or the other (probably in favour of the 30mm!)?

 

[Sea Skimmer]

The 30mm Apache gun isn’t a real high velocity design, and used only shaped charge ammo to defeat armor. A 30mm spin compensated shaped charge isn’t too awesome. It would be sucky on a ground vehicle because of those issues. If you introduced new ammo not used by Apache, then you just defeated the point of commonality. Apache cannot use discarding sabot because like any other aircraft, the sabots might be sucked into the engines. That would be very bad.

However someone did design a ground gun to fire Apache ammo. It’s called ASP-30 and can be used with a modified .50cal machine gun mount. Only a few have been built, but it’s available for sale and often seen on an M113 with an open mount. They even claim you can use it from a tripod on the ground, but the recoil and overall weight make this pretty unrealistic except maybe for static anti car bomb duty.

The US Army accepted 25mm for so long while most people went right to 30mm or 35mm because the US Army was willing and able to use a discarding sabot DU round for armor penetration. Most people couldn’t make that work at the time, or else rejected DU completely. However that is no longer felt to be adequate, and the new IFV design in the now canceled Future Combat System was going to have a 30mm Mk44 cannon, same as the Marine EFV.

 

[TomS]

I doubt that the "Bradley Warhammer" actually exists. There are no references to it outside of an uncited sentence in Wikipedia and a very few sites clearly lifting from Wiki.

 

[Sea Skimmer]

I doubt that the "Bradley Warhammer" actually exists. There are no references to it outside of an uncited sentence in Wikipedia and a very few sites clearly lifting from Wiki.

That is not true. You should look into books. Rapid Fire has a color picture of the thing, so I’m going to say it is very much real. The 35mm version of the Bushmaster III is actually in service with a couple nations too, but development of the 50mm ammo for the alternative 50mm caliber barrel was never completed, since the projected threat of new models of heavily armored Soviet IFVs never materialized.

A number of other even heavier 57mm and 60mm automatic cannons have been tested on infantry fighting vehicles and light tanks as well, so its not like a 50mm demonstrator is at all unreasonable. Upgunned demonstrators of armored vehicles are a dime a dozen and its not uncommon for one to appear at one or two arms shows, and then never be seen or heard of again.

 

[RyanC]

When one looks at the fact that the German's soon come to think that the 20mm cannon on their own pioneering Marder was to light and ineffective

Actually, it's important to look at the past experience of the Germans in WWII. They found that 20mm autocannon fire, whether it came from 20mm Flak 38s or from Armored Cars, was very useful in suppressing enemy infantry, and allowing an infantry assault to go forward. This was the major reason a 20mm was picked for Marder I; it would be able to support the infantry assault. As a side bonus, it could also somewhat explode very light skinned vehicles.

 

[Abraham Gubler]

The post war German Army also used 20mm guns as their standard light infantry battalion level direct fire weapon in a towed mount. They developed the Weasel airborne combat vehicle specifically to deploy the weapon for the parachute battalions. The Marder was upgraded from 20mm to 25mm to provide a better armour penetration capability to wash away the BMPs.

As part of the M2A2/M3A2 upgrade of Bradley Fighting Vehicles (BFV) replaced the internal storage of Dragon ATGMs with that of Javelins. On the M2A2 either five TOWs or three TOWs and two Javelins can be carried internally. The upgrade also replaced the storage for 66mm LAWs with 84mm AT4s. I haven’t seen anything in the PM HBCT reports for replacing the TOW 2 launcher with Javelin. It seems unlikely especially since extended range Javelin isn’t in production yet and would result in a significant range loss for the BFV.

A few BFVs have had the M242 25x137mm Bushmaster chain gun replaced with the 30x173mm Bushmaster II and the 35x228mm Bushmaster III chain guns for evaluation purposes.

From 1981 the Combat Vehicle Armament System Technology (CVAST) program replaced a BFV turret with a new cleft turret armed with a ARES 35mm Talon gun. The project’s name was changed to Combat Vehicle Armament Technology (COMVAT) and the 35mm replaced by 30mm and 45mm cased telescoped ammunition (CTA) guns from ARES. The cleft turret was sharply angled and had the TOW launcher fixed in the ready to fire horizontal position.

 

[TomS]

I doubt that the "Bradley Warhammer" actually exists. There are no references to it outside of an uncited sentence in Wikipedia and a very few sites clearly lifting from Wiki.

That is not true. You should look into books. Rapid Fire has a color picture of the thing, so I’m going to say it is very much real.

I've got my copy of Rapid Fire out and I'm not finding any such thing. There's a picture of a Bradley upgunned with a 35mm Bushmaster III, but that isn't what was asked about. The "Warhammer Bradley" mentioned by the OP and Wikipedia is supposed to be an M2A2ODS armed with Javelin (or Predator, according to the OP) anti-tank missiles in lieu of TOW. The picture in Rapid Fire does not show that--the launcher there is still pretty clearly TOW and there's no mention of a new missile.

Edit: fixed hyperlink

 

[silkmonkey]

Hi:

Thanks for all the feed back thus far, reading, I am thinking that maybe for what I need a 30mm gun on a Bradley IFV is what i should be looking for. Also if a long range predator missile is not in production can the Israeli SPIKE-MR or LR be used. I understand these weapons were basically refined upgrades of the TOW-II antitank missile system the use laser designation and tracking to illuminate a target, then when the missile is fired the missile tracks the target, locks on and destroys the target with out commands from the gunner in the Bradley IFV (meaning "Fire and Forget") would this be a better solution to what I am looking for? ???

 

[TomS]

Silkmonkey:

I'm not sure this is necessarily the right forum for what you want. Sounds like you're going a fantasy army sort of thing, which is kinda outside the realm of the Secret Projects forums. Anyway, here are a couple of minor corrections to what you have said here.

Predator is a short-ranged (<600 meters) missile developed for the US Marines; it woudl make a lousy vehicle-lauched missile due to that short range.

Javelin is the longer-ranged fire-and forget missile that replaced Dragon as the main infantry anti-tank weapon in the US military. As Abraham noted, the current versions of Javelin have less range than the current versions of TOW (especially TOW 2B Aero Wireless, which replaces the wire link with a radio signal). There is talk of an extended range Javelin, but it's not available yet. There was also a program to develop a fire-aqnd-forget TOW, but that got cancelled several years ago.

Spike is not really related to TOW, except that the ER version is about the same size and can replace TOW on some vehicles. Spike MR/LR are similar to Javelin in size and range. These missiles are fire-and-forget using imaging infrared seekers, with the option of fiber-optic data-links on some models.

I'm not sure what you're referring to as laser guided, since none of the missiles discussed here use that guidance mode.

 

[DanielStarseer]

Out of curiosity,
does anyone have any decent info (links, etc)
as to what requirements (I'm guessing back in the early 1970s)
led to development and eventual adoption of the now-NATO-Standard 25x137mm ammunition family?

Seems that Oerlikon also used it years ago, too,
in the 25mm KBA cannon (the KBB model using 25x184mm cases instead).

Seeing as the Bushmaster 25mm Chain Gun initially came about as armament for what was to become the Bradley (and then also as armament for USMC LAV-25),
I wonder why the US Army opted for 25mm, when the USAF was going 30x173mm for the A-10's GAU-8 cannon, also an early 1970s development...

More a political decision than actual tactical requirement?
Seems the 30mm would've been the better choice, in hindsight now.

 

[Abraham Gubler]

Oerlikon designed both the 25x137mm (KBA) and 30x173mm (KCA) rounds, the higher velocity 25x184mm (KBB) was for improved anti-aircraft performance. While the adoption of both rounds by the US forces may appear to be duplication in hindsight after the Bushmaster II gun was developed; it took 10-20 years to converge the two roles into one calibre. In the late 60s early 70s the US Army was looking for a way to fit more firepower into a 20mm gun package to defeat up armoured BMPs and USAF was starting from a clean slate for a far more powerful and bigger weapon. Since Oerlikon had been developing superior medium calibre rounds from the 1930s (24mm, 34mm) they were a natural source for anyone looking for good rounds post war.

 

[PG_69]

The Marder was upgraded from 20mm to 25mm to provide a better armour penetration capability to wash away the BMPs.

Outside of some products from GDW, Marder retained its 20mm......

 

[Apophenia]

The Marder was upgraded from 20mm to 25mm to provide a better armour penetration capability to wash away the BMPs.

Outside of some products from GDW, Marder retained its 20mm......

If all Marders retained their RH-202, was the Mauser MK-25 Model E actually produced?

 

[Grey Havoc]

https://apps.dtic.mil/dtic/tr/fulltext/u2/a129796.pdf

Initially, it was the Army's intent to develop a one-man 20mm
gun station MICV and produce it in the summer of 1976. However,
the Secretary of the Army directed a program review based on the
perceived threat for the 80s and beyond. As a result, the
Mechanized Infantry Combat Vehicle Task Force (Larkin Task Force)
was established in August 1976 which conducted a three-month
study to examine the requirements not only for the infantry
fighting vehicle, but also for the cavalry fighting vehicle.

The study recommended a two-man weapon station with both the 25mm
Bushmaster cannon and the TOW anti-tank missile, and that the
vehicle be common to both the infantry and the cavalry. The
recommendation was accepted by the Secretary of the Army in
November 1976. It was initially intended to place into production
the one-man station 20mm MICV until the two-man station
vehicle was ready. However, this approach was abandoned in March
1977 as not cost effective and all effort was directed toward
what is known today as the IFV and CFV. The Army no longer had
to support two fighting vehicle configurations.

Looks like the 'interim' M-2 would have indeed been equipped with the M139 20mm cannon.

 

[Tony Williams]

The second 20mm tested on it was called XM236, and appears to have been a revised M139, but I am not certain.

I can find very little on this, but it does seem to have been an M139 modified to a dual ammo feed (and possibly with other changes - although I think it retained 20 x 139 ammo). Do you have a source of info about it?

 

[jsport]

WARFARE TECHNOLOGY

A blog about the latest advances in military technologies on weapons, turrets, armored vehicles and land systems.

warfaretech.blogspot.com

 

[jsport]

Thank you Nick Drummond
Interesting slide that shows the Super40 upgrade of Northrop Grumman's 30x173 mm Bushmaster II cannon. The Super40 needs three spare parts. The ammo has a 20% uplift in case capacity. Ongoing efforts to improve 40x181 mm ammo make this a low-risk upgrade option.

 

[GSG]

Bradley never had a 20mm gun. The XM723 did, but it only served as a developmental basis for Bradley after it and the XM800 had been canceled. Bradley was designed with the 25mm Bushmaster and two man turret from the onset; it also had completely different suspension and a whole lot of other changes.

XM723 was tested with two different 20mm guns. The first was a Hispano-Suiza HS.820 designated as M139 in US Army service and firing a 20x139mm cartridge. It’s very powerful as far as 20mm cannon go, and in fact the 25mm Bushmaster isn’t that much more powerful in raw energy terms. However the HS.820 design was meant for aircraft and didn’t do so well in reliability when used on the ground, and 20mm was too small to work with 70s vintage discarding sabot ammunition. Thus the externally powered Bushmaster with higher caliber neatly solved both problems.

The second 20mm tested on it was called XM236, and appears to have been a revised M139, but I am not certain.
Prior to commencing work on Bushmaster, the US Army also looked at the 25mm KDA cannon, and the 20mm RH202 and fit both to improved M113 variants. The 25mm version became the AIFV, which was exported to Turkey, the Netherlands and a few other places.

The Bradley can easily be adapted to different calibers of guns, going down in caliber would be trivial. But for trials it has been fitted with weapons as heavy as the 50mm version of the Bushmaster III.

I trained on a m3a3 Bradley and it had a 20mm chain gun. Others were modified and had certain characteristics we needed....but it was absolutely a 20mm. Down-range we also had a m3a3 25mm version with ap and HEDP rounds. Don't reply to people unless you have a full view of what the army had on hand.

 

[isayyo2]

I trained on a m3a3 Bradley and it had a 20mm chain gun. Others were modified and had certain characteristics we needed....but it was absolutely a 20mm. Down-range we also had a m3a3 25mm version with ap and HEDP rounds. Don't reply to people unless you have a full view of what the army had on hand.

Could you point us to the relevant FM or ATP manuals about this 20mm Bradley? Especially pertaining to the conversion of barrel, ammo feed, and fire control system?

 

[GSG]

I trained on a m3a3 Bradley and it had a 20mm chain gun. Others were modified and had certain characteristics we needed....but it was absolutely a 20mm. Down-range we also had a m3a3 25mm version with ap and HEDP rounds. Don't reply to people unless you have a full view of what the army had on hand.

Could you point us to the relevant FM or ATP manuals about this 20mm Bradley? Especially pertaining to the conversion of barrel, ammo feed, and fire control system?

I was being a bit harsh, so I'll tell what I can. Although you give the Army too much credit by thinking they gave us field manuals on everything we used even as 19D

Different barrel in appearance, different motor, slightly different feed system. The manual controls/push buttons were all the same as the standard 25mm. The electronics and other bits and pieces were classified when I trained on them over a decade ago, and for all I know still are, so you'll have to dig on that for yourself.

Odd thing is everything was 100% brand new when we got it, so maybe it was a trial run as I never used or saw one again.

I do have to say those 20mm rounds fucked up armor plating better than the 25mm, by far, and pretty sure it had a different explosive payload than class B, RDX, or PETN based on what we saw.

 

[isayyo2]

Odd thing is everything was 100% brand new when we got it, so maybe it was a trial run as I never used or saw one again.

Thanks mate, I’ll leave that mystery for another day lol

Do you have any opinion on all the M3’s being converted into regular M2A3/4’s? Seems like the CFV was too cramped and they wanted more 19D’s in the Cav Troops.

 

[TomS]

I'd be very curious indeed to know when this training took place. Because as far as I can tell, no such thing as a 20mm Chain Gun was ever adopted by anyone. I can't even find reports of one being tested. Hughes started development of the Chain Gun in 1972 with the intent if making it fire 20mm ammo but the actual test guns fired 30mm WECOM (and later 30mmx113 in the M230). After that, no mention of 20mm chain gun anywhere until 2021 when NG announced the Sky Viper proposal for future helicopters.

 

[markfward]

I trained on a m3a3 Bradley and it had a 20mm chain gun. Others were modified and had certain characteristics we needed....but it was absolutely a 20mm. Down-range we also had a m3a3 25mm version with ap and HEDP rounds. Don't reply to people unless you have a full view of what the army had on hand.

Could you point us to the relevant FM or ATP manuals about this 20mm Bradley? Especially pertaining to the conversion of barrel, ammo feed, and fire control system?

I was being a bit harsh, so I'll tell what I can. Although you give the Army too much credit by thinking they gave us field manuals on everything we used even as 19D

Different barrel in appearance, different motor, slightly different feed system. The manual controls/push buttons were all the same as the standard 25mm. The electronics and other bits and pieces were classified when I trained on them over a decade ago, and for all I know still are, so you'll have to dig on that for yourself.

Odd thing is everything was 100% brand new when we got it, so maybe it was a trial run as I never used or saw one again.

I do have to say those 20mm rounds fucked up armor plating better than the 25mm, by far, and pretty sure it had a different explosive payload than class B, RDX, or PETN based on what we saw.

Are you sure you don't mean 30mm Bushmaster cannon?

 

[Foo Fighter]

If it was a 20mm, could they have been trialing a DU round? Might explain the reported results. A bit small though imo. Stuff does sometimes happen though.

 

[TomS]

If it was a 20mm, could they have been trialing a DU round? Might explain the reported results. A bit small though imo. Stuff does sometimes happen though.

Why change calibers for that, considering that the M919 25mm APSD-DU round entered service in 1996 (before the A3 Bradleys)?

 

[drejr]

Are you sure you don't mean 30mm Bushmaster cannon?

Fitted to a Bradley a decade ago, different barrel in appearance, apparently more powerful...

 

[BB1984]

The Marder was upgraded from 20mm to 25mm to provide a better armour penetration capability to wash away the BMPs.

Outside of some products from GDW, Marder retained its 20mm......

My recollection is that the Germans trialed the 25mm upgrade but then they got 20mm APDS working and that was judged both 'good enough' and far easier/cheaper than going to 25mm.

The 20mm ammunition upgrade was from the DM43 APCR, which had a great deal of trouble with the BMP-2 frontal armor, to the DM65 APDS which restored penetration out to 1000m or more.

 

[BB1984]

Seeing as the Bushmaster 25mm Chain Gun initially came about as armament for what was to become the Bradley (and then also as armament for USMC LAV-25),
I wonder why the US Army opted for 25mm, when the USAF was going 30x173mm for the A-10's GAU-8 cannon, also an early 1970s development...

More a political decision than actual tactical requirement?
Seems the 30mm would've been the better choice, in hindsight now.

Going to 30x173 means a bigger gun, especially relevant as it uses more internal turret space, and bigger ammunition, which means fewer rounds available, so there are trade-offs. You can stow 60-70% more 25mm ammunition in the same space as 30x173. More rounds means more engagements so, as long as the 25mm is 'good enough', it's a superior solution to the 30mm, or at least that's how the thinking goes. There's always the argument that too big a gun is much better problem to have than too small a gun, but the US Army doesn't think that way (see the M1 coming into service with a 105mm gun).

Also recall that the 25mm was an up-gun, for future-proofing, from the 20mm in service on, for instance, the Marder and AMX-10. The US did go heavier than the prevailing standard at the time.

Finally, during the Bradley development period the USAF was looking at moving from 20mm to the 25mm GAU-7/A for the F-15, and Mauser developed the BK-27, so there was some convergence on 25-27mm as an optimal caliber in preference to existing 30mm loadings.

 

[Nik]

With US moving towards 'deprecation' of DU tank rounds, will loss of the lighter DU type force a re-think in the 20~~30 mm zone ??

 

[TomS]

With US moving towards 'deprecation' of DU tank rounds, will loss of the lighter DU type force a re-think in the 20~~30 mm zone ??

The US is already shifting to at least 30mm (Stryker Dragoon/MCWS)

US Army chooses winner to build its new Stryker gun system

The Army has chosen who will build its Medium Caliber Weapon System for the Stryker combat vehicle.

www.defensenews.com

The current thinking is that the next-gen AFV may go up to as much as 50mm (basically a straight-sided Supershot-style upgrade to 35mm).

New 50mm Bushmaster Chain Gun at AUSA - Overt Defense

Northrup-Grumman has unveiled the XM913 50mm Bushmaster at this year’s AUSA (Association of the United States Army) trade show and conference

www.overtdefense.com

 

[Colonial-Marine]

With US moving towards 'deprecation' of DU tank rounds, will loss of the lighter DU type force a re-think in the 20~~30 mm zone ??

Is this a definite thing? Sounds like another politically motivated decision. Sure DU isn't good for your health but neither the effects of any heavy metals you'd use for the job like tungsten. For all the blame DU ammunition gets for Gulf War syndrome is there any proof it was caused by DU exposure versus dozens of other things it could have been ranging from breathing in fumes from burning oil wells to experimental drugs supposed to protect from exposure to chemical weapons? Or actual exposure to chemical weapons, destroyed or otherwise, the Iraqis had?

Regarding different chain gun calibers I think a variant of the Bushmaster in the higher power 25mm used by the Oerlikon KBB would have been pretty impressive. I've heard the caliber quoted as 25x173mm, 25x180mm, 25x181mm, and 25x184mm but I've no idea which is correct. Muzzle velocity must be very high.

 

[TomS]

Regarding different chain gun calibers I think a variant of the Bushmaster in the higher power 25mm used by the Oerlikon KBB would have been pretty impressive. I've heard the caliber quoted as 25x173mm, 25x180mm, 25x181mm, and 25x184mm but I've no idea which is correct. Muzzle velocity must be very high.

It appears the actual case length varied depending on the nature of projectile, so anything from 174mm to 184mm was possible with different loads. I've seen MVs as high as 1400 m/s quoted for the APDS round, which isn't much faster than 25x137 (which is around 1370 m/s). It is a heavier slug, though, so about 12% more muzzle energy (147 kJ vs 131 kJ).

Sources: Rapid Fire (by Tony Williams) and https://forum.cartridgecollectors.org/t/25x181kbb-apds-t-now-sectioned/10922/2

 

[Nik]

Uranium turning up in blood samples and aquifers ??

 

[Foo Fighter]

There are several links other than DU or whatever else comes up in this months conspiracy schmiracy magazine. In the UK, there had been a deliberate policy of removing stocks of Chemical and bacteriological pre and post exposure treatment systems. They also ran down stocks of standard vaccines and this was done to remove maintenance costs to the MOD.

This process concluded in the middle of 1990.

Cue Op Granby or the Shield/Storm twins the UK MOD realised they would need to ramp up for a full treatment program. In my last regular service spell I ran full hearing and vaccination programs for several units attached to my regiment so I know how this SHOULD be run. Not in Op Granby. We were denied access to batch numbers and expiry, vaccinated far in excess of the regimes accepted in used by anyone out there, including our own.

It was found that out of the vaccines we were given all but one were found to unfit for use and one (The Anthrax vaccine) was found to have chemical base elements that were illegal for use anywhere in the world. It has been suggested that there is no such thing as Gulf War Syndrome purely because the symptoms are so varied but, ALL of the symptoms track to the human immune system, this also makes it a syndrome.

In all of my efforts to find a base cause, the vaccination program comes closest, I cannot say what happened elsewhere in the TOO but I would suggest that there is a similar causation. Add the points I have already made to NAPS and BAPS pre treatment agents and the on off use of anti malarials, many of which have questionable efficacy which has been reported and you get a syndrome that effects people now decades after the event. Something that is common though is the lack of treatment for those with this debilitating problem because civilian health systems just do not know, or care, what they need to do. This I also know from personal experience.

If you ask the Saudi and Kuwaiti governments about the contamination they will tell you the most common was in fact hydrogen cyanide and there were papers about this but I think you will have to find them yourself, too much to do here.

 

[Tony Williams]

Regarding different chain gun calibers I think a variant of the Bushmaster in the higher power 25mm used by the Oerlikon KBB would have been pretty impressive. I've heard the caliber quoted as 25x173mm, 25x180mm, 25x181mm, and 25x184mm but I've no idea which is correct. Muzzle velocity must be very high.

It appears the actual case length varied depending on the nature of projectile, so anything from 174mm to 184mm was possible with different loads. I've seen MVs as high as 1400 m/s quoted for the APDS round, which isn't much faster than 25x137 (which is around 1370 m/s). It is a heavier slug, though, so about 12% more muzzle energy (147 kJ vs 131 kJ).

Sources: Rapid Fire (by Tony Williams) and https://forum.cartridgecollectors.org/t/25x181kbb-apds-t-now-sectioned/10922/2

This is the entry for the 25mm KBB ammunition in my new book, Autocannon: a History of Automatic Cannon and their Ammunition, which will get published sometime this summer..... I hope.

25 × 173/181 OERLIKON KBB
The 25 × 137’s big brother, developed from 1966, uses a lengthened version of the same case in two versions with different neck lengths: 181mm with Anti-Missile Discarding Sabot (AMDS) and other discarding sabot rounds, and 173mm for full-calibre TP-T and HE loadings (see photo below). To compli- cate matters further, this round was for a long time commonly referred to as the 25 × 184; at least one example with this case length is known, so it may have been tried in development.



Although the KBD rotary cannon was developed to fire it, the only service use is in the Oerlikon KBB single-chamber
gun, which itself has only been used in a naval CIWS which was purchased only by Turkey. Although it remains in service, it is being gradually replaced and it seems unlikely to enjoy a long future. The ammunition is no longer advertised.
Overall round length is 288mm and weight is 620g. Combat loadings are:

• HEI SD: 230g hardened steel shell with ballistic cap, contains 20g Hexal plus incendiary mix; base fuze with self-destruct function; MV 1,160m/s.
• APDS-T: 190g projectile with 14.5mm diameter, 156g tungsten alloy penetrator in a plastic/light alloy sabot; MV 1,285m/s; penetrates 34mm/60°/1,000m (also AMDS without tracer, and FAPDS; same ballistics).

 

[TomS]

Regarding different chain gun calibers I think a variant of the Bushmaster in the higher power 25mm used by the Oerlikon KBB would have been pretty impressive. I've heard the caliber quoted as 25x173mm, 25x180mm, 25x181mm, and 25x184mm but I've no idea which is correct. Muzzle velocity must be very high.

It appears the actual case length varied depending on the nature of projectile, so anything from 174mm to 184mm was possible with different loads. I've seen MVs as high as 1400 m/s quoted for the APDS round, which isn't much faster than 25x137 (which is around 1370 m/s). It is a heavier slug, though, so about 12% more muzzle energy (147 kJ vs 131 kJ).

Sources: Rapid Fire (by Tony Williams) and https://forum.cartridgecollectors.org/t/25x181kbb-apds-t-now-sectioned/10922/2

This is the entry for the 25mm KBB ammunition in my new book, Autocannon: a History of Automatic Cannon and their Ammunition, which will get published sometime this summer..... I hope.

25 × 173/181 OERLIKON KBB
The 25 × 137’s big brother, developed from 1966, uses a lengthened version of the same case in two versions with different neck lengths: 181mm with Anti-Missile Discarding Sabot (AMDS) and other discarding sabot rounds, and 173mm for full-calibre TP-T and HE loadings (see photo below). To compli- cate matters further, this round was for a long time commonly referred to as the 25 × 184; at least one example with this case length is known, so it may have been tried in development.

View attachment 675837

Although the KBD rotary cannon was developed to fire it, the only service use is in the Oerlikon KBB single-chamber
gun, which itself has only been used in a naval CIWS which was purchased only by Turkey. Although it remains in service, it is being gradually replaced and it seems unlikely to enjoy a long future. The ammunition is no longer advertised.
Overall round length is 288mm and weight is 620g. Combat loadings are:

• HEI SD: 230g hardened steel shell with ballistic cap, contains 20g Hexal plus incendiary mix; base fuze with self-destruct function; MV 1,160m/s.
• APDS-T: 190g projectile with 14.5mm diameter, 156g tungsten alloy penetrator in a plastic/light alloy sabot; MV 1,285m/s; penetrates 34mm/60°/1,000m (also AMDS without tracer, and FAPDS; same ballistics).

I hoped Tony might drop in. Thanks for the elaboration and correction.

Looks like I'm going to have to buy another of your books.

 

[Nik]

Thank you all, very informative.

"anti-malarials"

Uh, yeah. They are truly 'Wild Cards'. One of our quality managers went to far-east on an extended exchange to help 'boot-strap' local subsidiary QA/QC. His anti-malarial meds 'disagreed' with him. He wasn't just physically ill with ghastly dysentery, he had scary psychotic episodes, had to be hastily medevacked. Spent weeks in private UK clinic before his system stabilised...

One of my wife's friends has relatives in Singapore. Although the mega-city is officially malaria-free, given those 'effin anopheles' do not breed there, they may blow over the fence from Malaysia. Are you feeling lucky ?? So, wise visitors dose themselves with anti-malarials, and beware oft-bizarre side-effects. IIRC, there's neither rhyme nor reason to the problems. Some people are okay for for multiple visits, then are hit hard. Others dare not visit again, or are stricken during prophylactic ramp-up prior to travel, must cancel flight...

Tangential, I was aghast at related anti-malarials being touted as efficacious against Covid infection. I'm not surprised some of their loudest proponents often expressed bizarre opinions and, um, fractured reasoning...