Wednesday, November 28, 2012

40mm Case Telescoped Ammunition Time to take a look.


Cased ammo.

Maybe its time has come.  The US Army is looking into it for use with a light weight machinegun and the Brits ARE using it for their Warrior upgrade program.

My focus is on the use of 40mm CTA for use on the AAV upgrade/ACV.  We don't have to be wedded to the 30mm.  The Brits have already done the work on the development of the round and it offers much greater kinetic energy.  But what really caught my attention is that you can almost double the number of rounds carried by each vehicle and it allows for the weapon to be elevated beyond what you normally find in vehicle mounted main weapons.  I'm thinking urban combat...plus having the ability to punch behind barriers with one round instead of using multiple hits.

Read about it here.

15 comments :

  1. You can't double the number of rounds carried vs 30x173mm. 30mm is still significantly smaller.

    CTA's pitch is that their 40mm reduces the number of rounds needed for specific tasks to the point where it's a net gain in "stowed kills". This depends on the specifics of each engagement. Sometimes having fewer, larger 40mm rounds is better. Sometimes having more shots is better.

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  2. They are developing LMG & MMG CTAs.. (sorry for the acronym barf).

    They also have a HMG based on the .338 Lapua.

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  3. full disclosure on this. i have no idea. i only glanced at the topic before and a commenter suggested i take a look at it. a quick look through on CTA website has me thinking it has merit. all i'm saying is lets investigate it and see if it makes sense. bigger bullet+same or more rounds carried equals win to me. we'll see.

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  4. It's a neat concept and well worth looking at, but three things to keep in mind are:

    1. telescoped concepts have been around for awhile in everything from small arms to, IIRC, the 75mm ARES gun. Nothing's made it into service yet and we'll see whether the 40mm will be the first.

    2. the real comparison for the "bigger bang from a smaller gun" is to the 30x173mm necked out to the "super 40" round, which can supposedly be fired from a Mk44 just by changing the barrel and a couple parts in the feed mechanism (so buy 30mm now, use up your ammo stocks then up gun to 40mm or just use up the 30mm for training and go to war with the 40mm)

    3. A lot of the CTA advantage in armored vehicles is just that the round is shorter and thus easier to handle in a weapon with a shorter in board length into the turret. It's not necessarily that the ammunition is more volume efficient but rather that you may be able to store and handle the ammunition more efficiently.

    If you want to look in to this stuff you are going to have a hard time finding anyone who knows more than Tony Williams. I don't always agree with his opinions but it is rare when he doesn't know all the facts. Neat article from him about modern weapons the UK looked at for FRES, including 40mm CTA, here: http://www.quarry.nildram.co.uk/WLIP.htm

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    1. The Super 40 won't penetrate as well a the 40mm CTA, however you will be able to carry more Super 40 rounds in the same volume.

      How much penetration do you really need? Even the latest Russian and Chinese IFVs don't appear to be that heavily armored. The Super 40 (or even 30x173mm) may be good enough.

      OTOH, the 40mm CTA is close to a production system. The Super 40 has only had preliminary work done, AFAIK.

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  5. Thermodynamically, for a given propellant volume, the shorter and wider a case is, the more efficient it is. The internal flame front propagates over a larger area. At least, it does until the case is as wide as it is long. That is one of the reasons the long range shooting competitors use such stubby looking cartridges. (See 6mmbr.com). The usual downside with such a case is stove-piping when feeding rapidly because the projectile is out of proportion with the case. The CTA gains the efficiency by being short and wide while avoiding stove-piped feeds because nothing protrudes.

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  6. geez.

    i must be the only one that hasn't kept up with this technology.

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  7. Sol,

    The turret elevation also brings up the possibility of air-bursting rounds being used against low/slow airborne targets.

    And the 40mm CTA is being used in the FRES-SV as well. The French will be adapting it for some of their vehicles too, so lots of commonality going on. A lot of work has gone in from 2 major military producers here, so i'd assume it has merits. Lets not pretend the British and French have no idea what they're doing when it comes to guns, even the USMC use weapons designed and (partially) built in the UK (just up the road from me actually)!

    As for increased round storage, not sure how that is affected, but what I do know is that the weapon as a whole can be made more compact than the current 30mm weapon (something similar is mentioned in an above comment, I think its the same size as a 25mm cannon), which can mean reduced volume/wieght (Good for the AAV right?) or keeping the same turret volume and increasing the rounds stored by utilizing the now free spaces. Either way its an improvement.

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    1. well as much as i slam NATO that's the one thing they got right and one thing that can keep the alliance moving ...standardization in weapons if not in platforms. if the entire alliance moved to 40mm CTA then it would help in any future conflict. just like 5.56mm did it for rifles the same should be tried for when it comes to armored vehicle weapons. just my opinion. i also know that the move has been to larger caliber guns but still. i want dedicated shooters perhaps on gun aav for every 10 apcs. 50 cal RWS and then a 40 CTA (or even 30mm if no change is made) for the gun aav.

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    2. 40mm CTA is very small in board compared to an equivalent 40mm chain gun (firing the 40mm Bofors round), but the advantage in turret space consumed is much less when compared to the 30mm / 40mm Supershot or the 35mm / 50mm Supershot. See the site I linked to earlier for a comparison of the 'inside the turret' profile of these different weapons.

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    3. i'm taking it all in BB, but i'm late to this party. more on this later. trust me i'm beyond intrigued.

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  8. Hey Sol -glad to see you took my advice to look it up - interesting eh ?

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  9. you posted the press release a while back :)
    http://snafu-solomon.blogspot.co.uk/2012/10/cta-40mm-cannon.html


    http://www.dtic.mil/ndia/2005garm/wednesday/duckworth.pdf
    Page 4 is whats most interesting to me.
    The actual 40mm cannon is smaller than a 25mm cannon!

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