A decent amount of FCS info is over at Boeing's site: http://www.boeing.com/defense-space/ic/fcs/bia/flash.html United Defense's (UDLP) website: http://www.uniteddefense.com/ and at General Dynamics (GDLS): http://www.gdls.com/ There is not a ton of info up yet on final variants of the FCS, but many ideas are still being considered. Most likely, the LOS-C (Line of Sight, Cannon) will be a low-recoil 105mm. 120mm could be possible, as the Thunderbolt variant of the M8 Armored Gun System, and the Hagglunds CV90120, have shown a 120mm can be "harnessed" to safely fire from a light tank hull (under 25 tons.) As for armor threats from 2015 onwards, it is a fair assumption that not all threat nations we will face off against with the FCS will be equipped with the latest generation of MBTs mounting the most effective armor and countermeasures technologies. And the KE rounds of 120mm guns are not likely going to see sufficient armor capable of repelling their impact anytime soon (the expiremental British "electric armor" cannot generate the kind of power needed to absorb/deflect a tungsten or DU sabot round impacting at over a mile a second.) Certainly, the gun will be more than a match for anything but an MBT designed from 2010 onwards: the current generation of heavy MBTs: Leo2, Abrams, Challie, LeClerc, T90, etc, would be hard-pressed to shrug off the latest 120mm KE rounds, and flank shots from 105mm sabots will still penetrate them. Even the 90mm APFSDS rounds available for some of the more impressive (French and Belgian) 90mm guns on the market can kill a modern MBT with a flank shot, but it is unlikely we will "step down" to such a "low" caliber main armament until some dramatically new improvements of KE propulsive technologies are available. A feasible railgun and its associated power supply may well be available for an FCS in the 2015-2025 timeframe, and such a weapon, if firing 5-10kg rounds at more than 2 miles a second (over 3200m/sec) could relegate today's armor protection technologies obsolete. For now, bet on 105mm and 120mm weapons. 10-20 years out, we may well have a tank-mounted railgun..

From United Defense http://www.uniteddefense.com/pr/pr_20040913.htm Looks like a 120mm electrothermal cannon for the LOS variant..

Thanks but all of this site havent been updated for quite some time,I think they will go for a light low recoil 120mm gun for block I .the problem with modern armor is not penetrating its armor but it penetrating the FCS's armor , the ETC gun also looks like a more probable candidate for a block II upgrade but its not clear how close it is to being operational , another technology yo be considered is the RAVEN gun which can lower the recoil which is amajor problem on a 19 ton hull

THe article is from Sept. 13th 2004. How much newer information do you want? Theres no mention of the ETC being a "block 2 upgrade." "United Defense Industries, Inc. (NYSE:UDI) achieved an industry first recently when it successfully fired a 120mm Electrothermal Chemical (ETC) gun from a hybrid electric drive combat vehicle." Looks to me like it'll be ready in time for Block 1..

Man! You don't go to a defense contractor site for a week, and they post up all kinds of new stuff. I wasn't aware they could build a pulsed power supply capable of those power levels in a package small enough to fit in their (UDLP's) hybrid test vehicle (their FCS "precursor" systems technologies integrator.) RAVEN gun? I'm unaware of this. Care to elaborate more, ej? The two most effective ways to reduce recoil on such big guns is: 1) increase the recoil length. This allows the gun to "runout" its kinetic energy on a smaller recoil mechanism. As an example, the Rheinmetall Rh 105mm gun family has several variants with differing recoils for differing applications: the Rh105-60 generates a recoil force of 600kN over a 280mm (11inch) recoil stroke. But the Rh105-11 only generates 110kN of recoil, but the recoil stroke is drawn out to 925mm (about 36inches). Few internal hulls have sufficient room to handle 3 feet of gun recoil, so this application would be more ideal for an external overhead installation like on the UDES-19 and Stryker. 2) differing designs of muzzle breaks will compensate/alleviate a certain amount of recoil. Typically, the muzzle break vents propellant gas in a slighty reward or directly sideways direction to lessen the overall "forward push" of the propellant gases (but only after the shell has left the barrel.) In the case of a lighter ordnance and an advanced "pepperpot" muzzle break, the CV90120 and M8 Thunderbolt can mount the 120mm guns on their 22.5 and 20.8 ton hulls. Certainly, improvements in recoil mechanisms and gun weights will allow the heavy-caliber guns to mount on 20-ton class hulls. The 15 ton AMX-13/105 and 16.5 ton AMX-10RC both mount 105mm guns, each with a sufficient recoil mechanism and muzzle break. So certainly putting such heavy guns on light hulls is possible..

thanks doggTag,Im still not sure that they will use an ETC gun in the MCS.here is a link about the RAVEN cannon: http://www.asc2004.com/23rdASC/summaries/c/CP-02.pdf can they ever fit an EM-gun into a 20 ton class hull (including the power source and pulse power system)? It looks like that they could only manage to squeeze it into a 60 ton hull (or a 10000 ton destroyer)

ETC guns are a logical evolutionary step, leading up to full EM rail gun weapons. ETC uses high electrical energy inputs, but nowhere near what would be required for a rail gun. Think of ETC technology as being similar to a giant spark plug, like your car engine uses. And as developments in these power supplies improve efficiencies and power-per-volume ratios, certainly a couple decades from now we could see the early rail guns being tested in AFVs, with a full battlefield system ready 30 years out (if not sooner.) All speculation aside, I'm basing this off the level of power supply (internal combustion engines, battery technology, and electric generators and motors) efficiency improvements we have seen over the last 30 years..

Dont be fooled into believing a decision has been made regarding the choice of gun for the MCS vehicle. Trade studies are ongoing for the weapon selection...same goes for wheeled vs. tracked vehicles. With the recent shift to the right of the FCS program schedule, dont be suprised to see more technology mature and become the backbone for certain variants!! (ie; C2V, RSV, and MCS wont be in ILP until 2015)

Present power systems prohibit a 20-ton vehicle fielding an EM gun, obviously. An effective weapon has a launch-equivalent powerof ~80Mw. Conventional cannon store this in a powder bag; an EM gun requires a pulse power generator capable of achieving equivalent raq power bursts. You can use capacitors to mitigate some of these energy demands, but at great risk of running out of juice fairly unpredictably. An ETC combines the two principles; a pulse power generator provides the spark which triggers the chemical explosion which in turn accelerates the round down the tube. It's nowhere near as energy intensive (a fraction of the demand) as a true magnetic accelerator. Doggtag was spot-on to mention the cars spark plug. The spark plug is powered off your cars 12V battery, and draws a fraction of its total capacity, but is nesearry to kickstart the massive 200+hp engine without "wind up" time..

80Mw may have been a slight exaggeration :) Think more along the lines of 20Mw equivalent in a modern 120mm gun, which is still alot of energy..