Range Report Tank guns

[Forgetful Coyote]

Hi yall, wanting to know if there is anyone here that work with or have a bit of knowledge on tank guns. My main question is how do they get so much velocity out of them, specifically the rifled tank guns? For example, I have heard the M26 Pershing could fire an APC round at 4850 ft/s. Im not talking about APFSDS-light for caliber rounds either but ones that are full caliber and not so light. Is it the powders they use? Barrel length maybe?

 

[Greg Langelius *]

Re: Tank guns

Who told you that?. The 90mm gun M3 is listed as having an MV of 2700fps. Still pretty fast, but nowhere near 4850fps.

Greg

 

[The Mechanic]

Re: Tank guns

I was thinking the same thing Greg. At almost 5K that would just about wash the rifling right out of that thing. Smoothbore is a different animal all together. That is where you get some high fps.

 

[Greg Langelius *]

Re: Tank guns

That jibes with my sources. The M256 120mm Smoothbore tank gun used on the M1a1, -a2, etc. Abrams variants, German Leopard, etc., is listed with a muzzle velocity of over 5000fps with APFDS projectiles.

BTW, when you access the link, look for references to LAHAT ordnances. Very interesting.

Greg

 

[jbailey]

Re: Tank guns

MMMMmmmm a Rheinmetall 120mm gun... too bad they don't sell those things to the public. Fins instead of twist = insane ballistics!

 

[Forgetful Coyote]

Re: Tank guns

It was on Greatest Tank Battles, one of the old tank crewman actually claimed it fired an AP-C round at 4850. I agree it seemed pretty insane but I figured he wouldnt be lying. Thanks for clearing it up. Also yeah the LAHAT is something serious, probably the most advanced tank ordnance out there, and the most capable. Btw, I understand Steyr made that 14.5mm rifle shooting fin stabilized sabots, any idea on the BC of one of those compared to a full-caliber round? How would a finned sub caliber projo compare to a full-caliber boattail VLD type projo in downrange energy/velocity, both fired from same barrel and same amount of powder?

 

[The Mechanic]

Re: Tank guns

They made a SLAP and SLAPT round for the .50BMG. I was going to buy the smoothbore barrel for my Windrunner but ammo is so hard to come by I decided against it. That baby comes out at 4,000fps and will penetrate 19mm of armor plate at 1,500 yards

 

[Fred_C_Dobbs]

Re: Tank guns

MV for an M833 APFSDS "sabot" round fired from the rifled bore 105mm M68 main gun of an M60/M1 tank was 1500 meters/second. It used M43 thermoplastic elastomer propellant that combusted to produce 1181 Joules per gram of propellant. Stinks like hell, very acrid and stings the eyes.

 

[varmint53]

Re: Tank guns

Gain twist is a nought way of getting higher velocity out of a main gun or cannon,been doing that since WW1-WW2.

 

[Forgetful Coyote]

Re: Tank guns

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fred_C_Dobbs</div><div class="ubbcode-body">MV for an M833 APFSDS "sabot" round fired from the rifled bore 105mm M68 main gun of an M60/M1 tank was 1500 meters/second. It used M43 thermoplastic elastomer propellant that combusted to produce 1181 Joules per gram of propellant. Stinks like hell, very acrid and stings the eyes. </div></div>

How does the burn rate of that compare with something like Retumbo or H-50BMG? Would it offer any advantage over conventional slow burning powders in overbore cartridges? Ive been trying to find it again for a while now but I remember reading a long time abot some new liquid magnetorheological powder or something crazy sounding like that, that was supposed to offer large performance gains over what we got right now. Anyone know what Im talking about?

Also, does a fin stabilized sub caliber projo offer any advantage in retained energy downrange over a regular spitzer point boattail design?