Damian

1 hour ago, Toxn said:

It's funny how the second the Iraqis or Saudis take something into battle its reputation suffers.

 

Part of the reason that so few M1s were lost until recently is that the ones seeing combat were all being operated by the US. US tankers, whatever their faults, don't seem to be in the habit of allowing their enemies to shoot them in the nuts with modern ATGMs.

It takes awful middle eastern conscript armies to truly show all of the weaknesses of a tank design.

I actually watched carefully what were going on over there and I must say that M1's actually proved it's high survivability and crew protection.

Sure watching terrorists propaganda can make your brain melt down, however I seen many M1's in these videos that were hit several times by various weapons used by the terrorists, and even after such beating tanks were still functional.

Actually majority of losses were when vehicles were abandoned due to no reason, and later burned or stuffed with explosives and blown up by the terrorists. Heck even ATGM's, altough the most dangerous besides large IED/SVBIED's, are not always super successfull.

In my opinion, as someone who serve in military reserve, M1 is the only MBT I would agree to go in to battle... besides T-14 but we can safely assume that all 4th generation MBT's will be designed in similiar way.

29 minutes ago, Xlucine said:

The only safety improvements mentioned being better static charge handling and a lubricant to prevent stuck rounds

 

I doubt that a hole in the blast doors is a huge concern - while ammunition develops very high pressures in the chamber, the local pressure developed when burning with such an easy route to atmosphere will be much lower. Any hypothetical hole in the blast door will also be very small, so even with an appreciable pressure difference there won't be very much gas flowing into the crew compartment - I bet the penetrator that made the hole in the blast door will be a bigger issue for the crew.

Perhaps yes. However it seems that there is some improvement and redesign of the entire ammo compartment in M1A2SEPv3, but no details, I guess we gonna need to wait a bit more, maybe entire year for another DOT&E report.

Ammo racks for 120mm ammo was changed at least several times, 1st generation ammo racks hold only 17 rounds, so only 34 rounds in turret bustle in total, later it was changed to 18 rounds per rack so 36 in turret bustle.

There were also some changes to the ammo rack design and blow off panels.

These are original blow off panels for 105mm ammo racks.

These are 1st generation blow off panels for 120mm ammo racks.

These are 2nd generation blow off panels, and here the story starts to be interesting. As far as I know, this was attempt for quick reload mechanism for tanks. And it's the first time where ammo racks were connected with blow off panels. Idea was that for quick reload, using a crane, entire ammo racks can be replaced by pulling them out with a blow off panels. However for some reason it was unsuccessfull and the entire idea was droped but these blow off panels could be seen on some tanks.

These are 3rd generation blow off panels, it seems they are remanufactured 2nd generation blow off panels, with these attachement points removed.

And these are the newest 4th generation blow off panels and ammo racks. I have a theory that perhaps someone revisited the idea of ammo racks being connected with blow off panels, but instead for quick reload function, made this as additional safety meassure so blow off panel can pull off the ammo rack during ammo cook off event. Or perhaps both functions do not exclude eachother.

http://www.wegmannusa.com/mbt-ammo-racks/

Here you can see that blow off panels are flat but have two attachement points.

For comparision these is one of the older ammo rack types but I have no idea which one.

And drawing shows difference between 17 round and 18 round ammo racks.

PS. here is also something about improved ammo racks for USMC tanks. http://www.dtic.mil/ndia/2012mcsc/Shrader.pdf

31 minutes ago, Collimatrix said:

How can we tell that the crew compartment is unharmed from these videos?  Sure, there isn't any fire jetting out from the turret hatches like there would be if a T-72 got hit, but it takes a lot less than that to kill the crew.  A blast overpressure of 3.5 PSI (24 KPA) is sufficient to maim or kill.

The idea that the blow-off panel takes the ammunition rack with it is intriguing, but I don't think it actually works that way.  You can see the blow-off panel flying into the air in this image:

 

 

It might also be possible to stuff the blast doors inside the turret with a lot of loose, hinged pieces of metal sandwiched in between two layers like so:

 

That might work, but I see no evidence that the Abrams' blast doors are anything but solid steel.

There are at least several types of blow off panels and ammo racks used in M1 series, the current newest ones are so called 4th generation. It's possible that older generations didn't had this solution, and not all Saudi tanks were upgraded from basic old M1A2 to newer M1A2S that is besides armor and some other minor stuff, equivalent to M1A2SEPv2.

As for blast doors, it's hard to say for certain what is their construction based only on visual inspection.

Altough I do not understand your remark about presure, what this have to do with M1 if the crew is isolated from the ammo storage?

Ok so now about something older.

Currently the basic carbine is wz.1996 Beryl in various versions.

This is wz.96A a basic variant and my currently issued weapon as a soldier of National Reserve Forces, it's a pretty nice weapon compared to AKMS I had during my basic course, I like it's stock, much better than AKMS stock, new fire mode selector is a good thing, at least for people with right hand being their dominant one.

This is wz.96B, a very rare model, that was designed during our mission in Iraq if I am not mistaken, never actually seen them in person, it was first attempt to integrate Beryl with picatinny rails.

And this is newest wz.96C (also known as wz.2004), it uses new hand guard with integral picatinny rails, new stock with adjustable lenght, interesting thing is that primary picatinny rail is detachable from upper receiver.

http://www.works11.pl/upload/products_img/21/2.jpg

This is wz.96C Mini Beryl, sub carbine version for vehicle crews, and soldiers that need a lighter and more compact weapon.

And this is experimental variant called sometimes wz.96D, it have new iron sights attached to picatinny rails, primary rail is now integral part of upper receiver, also it have new magazine well that can use standard STANAG mags. Upper receiver cover is also now on a hinges.

Beryl M762 for 7,62x39mm ammo, currently purchased by Nigeria.

Comparision of 3 variants of Beryl, from top wz.96C, M545 for 5,45x39mm, M762 for 7,62x39mm.

Also it's worth to watch some more videos from FB.

1 hour ago, Bronezhilet said:

I kinda find it amusing, that this is this notion that the M1 is pixel perfect. It's not a fantastic concept that solved all the great problems with tank and crew survivability... but it's an American vehicle, and that means it must have no weaknesses.

Stop pretending there is nothing wrong with the M1. It has a couple of problems and weaknesses, just like every other tank. This is SH, not "M1 Circlejerk United". If we think something has something worth discussing, we'll discuss it. If it turns out to be a weakness or a strength, we'll talk about how and/or why. But apparently you think we're not allowed that, because apparently it's faultless. We're discussing that it might have faults, but you think that's bullshit because of ...? Apparenlty we are to believe you because you say so and because of muh American superiority. Spoiler: We don't.

 

Oh, in both of those videos the HEAT jet would not intersect the crew compartment, because of the impact angle.

I don't know if you noticed that it was sarcasm, and irony, do not take it so personal.

I never said M1 is perfect, but so far it's the only mass produced tank that have such high crew survivability, and also vehicle survivability properties thanks to compertalization of main gun ammunition.

It's a fact. That's all, and I am certain that engineers working on the project taken all possibilities in to consideration.

As for videos, these are hard evidence, you have something better? Feel free to post it.

8 hours ago, Belesarius said:

I love the look of the MSBS bullpup carbine for some goofy reason.  It's very futuristic looking.

 

It's extremely ergonomic for a bullpup, altough I was trained with classic configuration weapons in the army, and I found it in the first place a bit awkward to handle... training needed I guess.

I kinda find it amusing, that there is this notion to find a weakness in M1's isolated ammo storage. It's fantastic concept that completely solved one of the greatest problems with vehicle and crew survivability... but it's American vehicle, and it must have weakness there.

Here we have two example of a turret bustle hit from the rear by ATGM's, with the ammo cook off event, and still, yet the crew compartment is not compromised.

So yeah, maybe I gonna show here some of the more recent development. Let's start with our latest projects, the MSBS and PR-15.

MSBS (Modułowy System Broni Strzeleckiej - Modular Small Arms System) as it's codename says is program focused on developing new family of modular small arms for military, law enforcement and civilian use.

The first variant is developed for NATO 5.56x45mm cartridge.

What is interesting is that MSBS is based on a single, common upper receiver to which various modules can be attached thus creating several weapons types in both classic and bullpup configuration.

1. From top to bottom in classic configuration.
- Carbine

- Rifle

- Rifle + under barrel granade launcher

- Magazine fed LMG

- Marksman rifle

- Ceremonial rifle

2. From top to bottom in bullpup configuration.
- Carbine

- Rifle

- Rifle + under barrel granade launcher

- Magazine fed LMG

- Marksman rifle

Also MSBS for 7.62x51mm cartridge is being in development, both as marksman rifle to replace the SVD, and also as a battle rifle.

MSBS was also adopted for 7.62x39mm cartridge seen here compared to 5.56x45mm variant.

Also a 12 gauge shotgun variant is considered and seems to be in early development stage.

Worth to mention is that also a 40mm UBGL was redesigned.

Original design was replaced with new, more classic and more compact one.

Also older GPBO-40 and other types of UBGL can be used.



 

Here is episode of Our Army where we can see a great presentation of MSBS ergonomics and functionality. It starts at 3:20.

Few words of my own experience with the rifle, it's a bit heavier than standard wz.96 Beryl rifle I am now issued with as a reservist in the army, however MSBS is extremely ergonomic, in terms of ergonomy it's better than AR15 or G36 I also had chance to get some time with.

Also during last MSPO I talked with one of the FB engineers working on the project and it seems everything is going well, rifle meet and as I was said even exceeded reliability requirements.

MSBS will also receive new magazines despite a fact it can use standard STANAG mags.

A standard 30 round magazine.

10 round magazine.

Special magazine for blanks only for use in ceremonial rifle variant.

Another new weapon designed by Fabryka Broni is new service pistol PR-15 it's general design can be called evolution of MAG-95/98 pistol, also designed by Fabryka Broni, it's fully ambidextreous, and is a really nice pistol, also had it in my hands during last MSPO and it feels good, very ergonomic.

That's all for now.

8 minutes ago, DD000 said:

 

Am I reading this right? This graph seems to state that there's a 120mm KE round introduced in 2003 that penetrates 950mm armour. I assume it's referring to the M829A3, but 950mm is way higher than even the most optimistic penetration estimates for it I've seen. 

There also seems to be a pretty large increase in protection from US 1992 levels to 2002 levels (from 650mm to 850mm). I also assume that this is the upgrade from the M1A2 to the M1A2 SEP, but it's surprising as well. I thought the SEP upgrades were mainly to its electronics, with some upgrades to its armour, but nothing so dramatic. Do you suppose that the CE protection to KE protection ratio has remained constant all this time? If the original M1 had 400mm KE protection and 750mm CE protection, then...

M1A2: 650mm KE, 1219mm CE

M1A2 SEP: 850mm KE, 1594mm CE

It's all some old fantasy estimations, based on god knows what. I would completely ignore this, as it's waste of time to take interest in all these estimations.

3 minutes ago, Scolopax said:

Concerning the Krab, what is the rational for mating two different foreign vehicles together (AS-90 turret and K9 hull), instead of just getting the entirety of one or the other?  Is it a cost thing perhaps?

To understand this situation we need to get back to the 90's. The original concept was, that Poland would purchase a turret and armament system, preferably as a license, and then mate it with domestic chassis, the UPG.

However UPG chassis was a complete failure, primary because it uses subcomponents from T-72M1/PT-91 tanks that are not designed for vehicles weighting way over 50 metric tons, and AHS Krab weights 55 metric tons when based on UPG chassis. And there were also problems with quality of steel used and welding, that lead to micro fractures.

Besides let's be honest, engine, transmission, cooling system, suspension etc. Are obsolete, army simply didn't liked UPG chassis.

But we got it right with the turret that was fully functional and meet or exceeded requirements. It would be then waste to purchase a complete new system, so decision was made to discard UPG chassis and purchase a better foreign chassis, choice was the South Korean K9 chassis.

Now the army is extremely happy with AHS Krab based on K9 chassis, it actually not only meet but exceeded all requirements.

Now about some good stuff, heavy armor.

T-72M1, we have around 350 these tanks in total, with around 159 in active service. No upgrades are planned for them, and are meant to be replaced as soon as it will be possible.

PT-91 "Twardy", Poland have around 232 of these in active service. Improvements over standard T-72M1 include, new 850HP diesel S-12U, new explosive reactive armor ERAWA-1 and ERAWA-2 (I will post separate informations about them later), fire control system Drawa or it's improved variant Radew, improved TPD-K1 day sight and also thermal sight, there are two variants of thermal sights, older Israeli made TES, and new Polish 2nd gen FLIR KLW-1 "Asteria". Vehicle is also equipped with self defense system SSP-1 Obra-3 which includes both laser warning receivers, and new smoke dischargers Tellur mounted on the both sides of turret. Other major improvements were only included in export variants PT-91Ex, PT-91M and PT-91P. There was also a technology demonstrator called PT-16 that is a proposal for T-72M1 and PT-91 tanks upgrade, however the proposal contains two solutions for turret, either rebuild + addon armor for existing turret, which was presented on the technology demonstrator, and second, probably new welded low profile turret based on the UMPG Anders design.

PT-16 technology demonstrator.

Poland purchased from Germany 142 Leopard 2A4 tanks, currently upgrade codenamed Leopard 2PL is developed by Rhinemetall and polish industry.

Leopard 2PL technology dekonstrator.

Besides Leopard 2A4's, also 105 Leopard 2A5's are in service.

BWP-1 as BMP-1 is called here, we still have around 1268 of these antiques in service, tough replacement for them is currently in development, codename "Borsuk". It is still uncertain if "Borsuk" will be based on domestically designed chassis, or on foreign one purchased via license, both options are currently considered, also issue with amphibious capabilities are debated, initially there was requirement for new IFV to be amphibious, but after intelligence reports from Ukraine, now it's considered that perhaps heavier armor is a better choice.
 
Also new IFV "Borsuk" will be equipped with unmanned turret ZSSW-30. Armed with 30mm ATK Mk44, 7,62mm coax, and Spike ATGM's. Same turret is also intended as upgrade for Rosomak wheeled IFV.

Early concept model of IFV "Borsuk".

Now about Rosomak, this is the basic Rosomak M1 variant which is literally just wheeled IFV, equipped with manned turret Hitfist-30P armed with 30mm Mk44 and 7,62mm coax, there is also planned upgrade for these turrets to equip them with Spike ATGM's launchers.

Here is also IFV variant with unmanned turret ZSSW-30 prototype on the firing range.
 
There were many more specialized variants of Rosomak developed. For example fire support variant with 105mm gun or 120mm gun, yet these are not ordered by Polish Army, tough 120mm variant might be eventually ordered.

Rosomak/Wilk armed with 120mm gun.

Rosomak-M with upgraded Hitfist-30P turret, as well as new addon armor acting also as buoyancy elements improving vehicles amphibious capabilities.

Experimental Rosomak-XP with improved suspension and armor protection + some minor improvements.

Rosomak WRT, you can consider it as ARV variant of Rosomak family.

Rosomak WEM.
 
Of course there are many more variants in development.
 
Another interesting R&D program was UMPG Anders for modular tracked platform.

Single technology demonstrator was build and later to prove it's modularity reconfigured in to several variants, these were.

Light tank with 120mm gun in low profile manned turret.

Light tank with 105mm gun in CT-CV turret.

IFV variant with Hitfist-30P turret.

IFV with unmanned Hitfist-OWS turret.

Unmanned autonomous tank destroyer with Spike ATGM's in AMUR weapons module.

Improved IFV variant with new version of Hitfist-30P turret with Spike ATGM launchers.
 

It's an older video but worth to watch.

I will describe situation with our heavy armor a bit later, but now also very important topic, artillery.
 
Let's start with new 155mm self propelled howitzers. There are two projects, wheeled and tracked, let's start with the later one.
 
155mm AHS Krab is a tracked self propelled howitzer based on modified british AS90/52 turret and south korean K9 chassis, initially desire was to use domestically designed and produced UPG chassis, but because it was based on T-72 tank components that were designed for vehicle weighting below 50 metric tons, and Krab weighted 55 metric tons, it's performance was rather poor. Also quality of that chassis didn't meet army requirements so decision was made to use foreign chassis in the end. Only 8 AHS Krab vehicles on older UPG chassis were made, and are currently used for crews training.

This is old Krab on UPG chassis.

And this is new Krab on K9 chassis.

Currently AHS Krab passed all factory and state trails and is mass produced at the moment with first units being inducted in to service. Hulls are now made in South Korea, but production of these hulls will be moved to Poland. The good thing is we purchased full license, which means we can also modify these hulls design and use for other applications, as well as reexport them. Also if Norway or other European countries would purchase South Korean K9 Thunder, it's possible that these would have made hulls in Poland, and Poland would become service center for them.
 
AHS Krab will replace 122mm AHS 2S1 Gvozdika and partially 152mm AHS Dana.

Here you can watch production capabilities of the HSW factory.

Another project, directly to replace AHS Dana is AHS Kryl.

AHS Kryl is designed as lightweight and very mobile system to supplement heavier AHS Krab. While Krab is intended to support heavy formations like Armored and Armored Cavalry Brigades, Kryl will support mainly medium formations builded around family of wheeled combat vehicles Rosomak. Kryl uses Israeli ATMOS 2000 howitzer based on new model of Jelcz truck.
 
To supplement these, there is also developed universal turret module with 120mm mortar Rak with autoloader, there will be two variants, wheeled SMK 120 Rak-K, and tracked SMG 120 Rak-G. Right now there are performed final preparations for starting mass production of SMK 120 Rak-K based on Rosomak chassis.

As I mentioned, turret module is universal, so can be installed on wheeled and tracked platforms, but also on static platforms/fortifications or navy vessels.
 
Now about rocket artillery.
 
The primary MLRS currently used is WR-40 Langusta, which is modrnized BM-21 Grad, wich increased range, crew protection, mobility, communications etc.

There was also project of WR-40 Langusta-2 which had additional missile rack with autoloader for rapid reload.

It was however not purchased yet by Polish Army, it might happen when more WR-40's will be ordered to replace last BM-21's and RM-70's.
 
The last project is WR-300 Homar, right now the prefered offer is polonized US M142 HIMARS system.

This is how it can look more or less, using the same Jelcz truck model as 155mm AHS Kryl.
 
Additional double purpose system are NSM missiles used in Coastal Missile Squadron (currently one in service, second on order), besides capability to attack enemy vessels, it have also secondary mode, that gives it capability to attack and destroy ground targets.

I am certain tough that during development it was taken in to consideration such possibility and it was somehow solved.

One possibility is that the problem might had been solved with ammo racks and blow off panels design, where ammo rack is directly bolted to the blow off panel, and the concept is that in case of ammo cook off, when blow off panel is... well blow off, it takes outside also the entire ammo rack.

Proof of that might be this photo of Saudi Arabian M1A2/M1A2S.

We might assume that due to hit blow off panel was blown off taking out ammo rack, but the process was incomplete because ammo rack was empty and there was no ammo cook off that would create sufficent pressure to blow away entire ammo rack with blow off panel.

2 hours ago, AMX-56 Leclerc said:

 

Hmm, I didn't know that, thanks for the info. IT just seemed too me that the CITV would be obscured by the hatches, GPSE, and RCWS more so than other tanks.

Not really, RCWS have a 360 field of view, CITV as well. Sure all these additional shields can obscure a bit the view for CITV, but these shields can be taken off as they are just additional modules used for COIN operations.

In M1A2SEP, both CITV and CROWS can be used in auto scan mode. This means that CITV in auto scan observes one sector, CROWS in auto scan observes second sector, and third sector is observed by the gunner.

Commander on his displays can simultanouesly observe images from both CROWS and CITV, and CROWS have not worse optics than CITV and gunner primary sight.

I was inside M1A2SEPv2 with CROWS mounted, and honestly, visibility from commander cupola is extremely good, better than in case of Leopard 2A4 or Leopard 2A5 commander cupola.

Besides that, M1A2SEPv3/v4 will receive new low profile CROWS which is lower and smaller.

Merkava Mk1, Mk2 and Mk3 have indeed a magazine on the turret floor.

Here you can see how ammo is stored inside vehicle.

In case of Merkava Mk4, ready magazine is isolated behind armored bulkhead in turret bustle.

As for how ammo is again loaded in to the ready racks, it's simple, if there is time, loader will take one round from storage container at a time, and load it in to the ready rack.

I guess in case of emergency, main gun can be directly reloaded with ammo from storage containers.

The general rule is that flames, gases and other nasty stuff will seak easiest way outside, and this easiest way outside is through blow off panels, and not a tiny hole made by shaped charge jet or KE penetrator.

I think the best would be a small experiment, let's take a small box, made from metal, fill it with something that burns violently, like potassium nitrate, make a small hole in one bulkhead, and cut out two larger holes in roof, maybe cover them with something light, like cardboard to simulate lower weight of blow off panels, and see what happens.

One note tough, I never seen any material showing that when armored blast doors were closed, even with hit from behind, flames get inside crew compartment.

And there are at least two filmed incidents where M1 was hit in the turret rear, and at least on one video we can see that flames did not get inside crew compartment.

55 minutes ago, Toxn said:

I wonder what titanium gets you over steel, beyond weight?

Is there any word on how well aluminium alloys work?

AFAIK Titanium alloy used in armor provides some advantages over steel besides weight. Some materials to read.

http://c.ymcdn.com/sites/www.titanium.org/resource/resmgr/2005_2009_papers/Gooch_Final_2007.pdf
http://c.ymcdn.com/sites/www.titanium.org/resource/resmgr/2010_2014_papers/GoochWilliam_2010_MilitaryGr.pdf

19 hours ago, Collimatrix said:

 

We've had this link in the resources section for a while on TMEPS.  The engine was not "a standard AGT-1500," as the document explains, it had a new high pressure turbine rotor, new high pressure turbine cylinder, new recuperator, new power turbines, a new electronic control unit and a new auxiliary power take off.

Thanks for informations.

12 hours ago, Walter_Sobchak said:

Its funny, I never noticed that bit about the possibility of the transverse mounted AVDS-1790 in an Abrams before.  I know I had asked my dad once about transverse mounting the AVDS and he said Teledyne had asked Allison long ago about designing a transmission for such a mounting and Allison said there wouldn't be enough room for the linkages.  The reality was that Allison didn't want to do it.  For Allison, it was more important that they didn't piss off General Dynamics, who would not have appreciated Allison helping out their competitor, Teledyne Continental. 

I guess here the problem was the fact that US Armed Forces were happy at that time with AGT-1500, as it's reliable engine that meets requirements, and for a long time there was no requirements from DoD, thus there was no coordination, every attempt to find replacement was purely industry initiative. Only recently US Army started seriously look at AGT-1500 replacement, and we gonna see what will happen.

Propulsion systems and suspension

As mentioned before, M1 was designed with different types of engines and transmissions in mind. And indeed various types were tested, besides the standard AGT-1500 gas turbine engine, and tested as a competing design AVCR-1360 diesel engine, various different alternatives were tested.

One of the less known was AGT-1500 TMEPS (Transversly Mounted Engine Propulsion System), it was a standard AGT-1500 just mounted transversly to free up more space in the hull.

Another alternatives were LV-100-5 gas turbine engine and XAP-1000 diesel engine.

LV-100-5 was considered as new common engine for M1's and XM2001 Crusader self propelled howitzer. XAP-1000 was meanwhile tested in CATTB technology demonstrator.

http://www2.l-3com.com/cps/cps/1500_hp.htm

Another rare alternative would be to use 1500HP version of the well known and extremely reliable AVDS-1790 diesel engine, two configurations were proposed, one with standard mounted engine, and second with transversly mounted engine.
 

Finally we have a GDLS proposal to use the compact MTU MT883 diesel engine in 1650HP version.
 

As another alternative, a new BAE hybrid diesel-electric drive for heavy tracked vehicles, also can be potential candidate for AGT-1500 gas turbine replacement.

For the M1 at the moment only two types of transmissions are considered.

The currently used Allison X-1100-3B and Allison 5250MX.

http://www.allisontransmission.com/docs/default-source/defense/11568_atm_sales_sheets_x1100-3b.pdf?sfvrsn=2
http://www.allisontransmission.com/docs/default-source/specification-sheets/11119_atm_5250mx_sales_sheet.pdf?sfvrsn=2

When it comes to suspension systems, again, M1 was designed in mind, with capability to use different types of suspension.

This photo shows us very unique designs solution, of modular attachement points for suspension systems. This means that different types of suspension can be used besides standard torsion bars, it makes also upgrades for suspension easy and cheap as it does not demand expensive and time consuming cutting and welding work on suspension attachement points.

At the moment only alternative considered for torsion bars suspension system is hydropneumatic suspension system.

In the past Gadillac-Gage In-Arm system was tested, at the moment however avaiable is L-3 hyropneumatic suspension system model 3870.

http://www2.l-3com.com/cps/cps/3870_suspension.htm

In general these engine and suspension upgrades can be included in another ECP modernization phases.
 

I stand corrected then. Now the question is, how long is XM360/XM360E1 compared to M256.

Does anyone is aware what are magnification levels of the gunner and commander sights of the Merkava Mk4? Or such trivial thing is considered as OPSEC?

3 minutes ago, Xlucine said:

Welcome to the forum!

 

 

I'd disagree with you here - the breech on the XM360E1 is clearly much larger than the XM360. Given these are meant to be very similar weapons, and a redesign of the breech would invalidate all the testing spoken about in the presentation, I suspect that those images are not to the same scale. A longer barrel would warrant mention in the 'key changes' section, so it's more likely that the barrel lengths are the same

Well it is possible of course, truth to be told we don't know a lot about either XM360 and XM360E1, simply because informations are rather limited.

Firepower

When it comes to M1's main armament, there is a bit of confusion as well. We can see in many sources that it's often said that both 105mm rifled M68/M68A1/M68A2 gun is a license copy of the British 105mm rifled L7 gun, or that 120mm smoothbore M256 gun is a license copy of the German, 120mm smoothbore Rh120.

The M68 series were actually 100% designed in US, and the experimental variant was called T254, it only happens that because of US-British agreements, bith M68 and L7 can fire the same ammo types and have interchangeable barrels. Also US used the bore evacuator of the assymetric design from the L7, while T254 in it's original form had symetrical bore evacuator, that caused some problems when gun was fired at minimum depression.

Informations can be found in Richard P. Hunnicutt Patton - A History Of The American Main Battle Tank Vol.1 and Abrams - A History Of The American Main Battle Tank Vol.2.

The primary characteristic of US gun is the concentric recoil mechanism that allows the gun to be more compact, so it's either easier to fit it in to a smaller gun mantlet or a smaller turret. While many other guns designs use eccentric recoil mechanism that takes a bit more space.

Also the gun breech is different in M68 series and L7 series. We can see it on videos showing interior of the M60A3 and Centurion.

Similiar story with the 120mm smoothbore M256. It's based on the Rheinmetall gun technology, but it's not license copy of the Rh120. Both guns can fire the same ammunition but are not interchangeable, simply Rh120 would not fit the M1A1/M1A2's gun mantlet. Also recoil mechanism is different, breech is slightly different, different are MRS, cradle, thermal shroud and bore evacuator.


This is the M256 in M1A1/M1A2.

And this is Rh120 in Leopard 2.

What is interesting tough, majority of countries using 120mm smoothbore guns, base their design on the M256 not Rh120, probably because M256 offers this compactness.

For example Israeli MG251 and MG253 guns are based on M256. Also South Korean and Turkish 120mm L55 guns seems to be based on M256 (or rather M256E1 that used L55 barrel).

Turkish MKEK 120mm smoothbore L55 gun.

As for source for Israeli guns, my source is this book written by Paweł Przeździecki.



As for M256E1, we have two photos that might actually present this gun, one mounted in M1, that probably served as a test bed, and second mounted in M1A2.




The new gun developed for M1A1/M1A2 is the XM360E1, however it's not certain if it will be used altough US Army showed some interest.


http://www.dtic.mil/ndia/2010armament/WednesdayReunionDavidSmith.pdf

 

It's a further development of the XM360 120mm smoohbore low recoil gun for the XM1202 MCS light tank. And there is some interesting observations we can make from CAD models and official statements. It's definately lighter gun, more compact than the previous generation guns. Also we know that XM360 was able to fire exactly the same ammunition with the same performance as M256, and here interesting bit, as we can see on screenshot, it is said, M360E1 compared to XM360 can fire ammunition with higher impulse and higher chamber pressure. Which means it's more pwoerfull gun than M256 or Rh120 or other comparable 120mm smoothbore guns. And it's kinda similiar to for example what Russians did with their new 2A82-1M 125mm smoothbore gun that can fire rounds at higher chamber pressure than previous generation 125mm smoothbores.

Another things we can note is that XM360E1 is longer without muzzle break than XM360. AFAIK XM360 had a L48 barrel, so this can mean that XM360E1 have L50 barrel, maybe longer, something like that. And another interesting bit about these guns are locking lugs, XM360 and XM360E1 have 6 locking lugs, compared to M256 or Rh120 2 locking lugs. Again suggests that these guns were designed with higher chamber pressure in mind.

We can also note that both XM360 and XM360E1 does not have reactive bore evacuator, so perhaps compressed air is used in both?

But returning for a moment to locking lugs, I found that 6 locking lugs is nothing new, actually it was present in some of the previous development like 120/140mm XM291 smoothbore gun and 155mm XM297E2 gun-howitzer for XM2001 Crusader.


XM291, photo is of bad quality but we can see more than 2 locking lugs.
 

Video of XM2001 compared to M109A6, but we can clearly see breech of the XM297E1 gun-howitzer with the same pattern of 6 locking lugs as in XM360/XM360E1.

So what about the future? As I said earlier and I found digging through various official US Army websites in various documents that, indeed, there are some consideration of replacing M256 with XM360 (or rather XM360E1), but what I also found interesting, they also consider using autoloader for the M1, and here it also starts to be interesting. There were two designs of autoloaders for M1A1 and M1A2. First was developed by General Dynamics and was codenamed FASTDRAW.



 

More about it can be read in ARMOR Magazine issue from 1995 page 18 in PDF reader.

http://www.benning.army.mil/armor/eARMOR/content/issues/1995/MAR_APR/ArmorMarchApril1995web.pdf

In general I recommend to take a look at various issues of ARMOR Magazine -> http://www.benning.army.mil/armor/eA...ackIssues.html

Another type of autoloader was developed by Meggitt Defense, and it's called Compact Autoloader. Unique feature of this autoloader type is a fact that it have two parts, it's automated magazine and the autoloader itself, and automated magazine can used without autoloader, so it would work the way that it automatically move selected round to the ammo port where human loader can take it and load it in to main gun.

https://www.meggittdefense.com/images/stories/pdf/PD_120mmCompactAutoloader.pdf
https://www.meggittdefense.com/images/stories/pdf/PD_120mmAutoloaderMagazineNEW.pdf
 

Some other unique features of US made tank autoloaders like FASTDRAW or Compact Autoloader is that they can both load and unload the main gun, as well as their high ammo capacity compared to other systems.