Large weapons, smoothbore vs Rifled

Originally posted by Jehosephat
Reports for the Gulf war states that the Abrams normally engages the enemy at 2000m but was able to effectivly engage at 4000m. The the fact of Rifling being more accurate doesn't hold much wieght, especailyl with Ballistics.

Reading some comments from former tankers, specifically a Master Gunner, one downside to rifling is the increased dispirsion of the explosion on impact. Thus robbing the progectile of some prenetration ability

In January 2004, Land Systems was awarded a contract to develop a new smoothbore 120mm gun for the British Army Challenger tanks. Rheinmetall of Germany will provide examples of the L55 smoothbore gun fitted on the Leopard 2A6 for the programme. A technical demonstrator will be produced by 2006.

I seem to also recall that there was a problem of getting the ammo for the rifiled main gun and that the supplier was overseas on not domestic. So instead of having ot rely on foreign sources for the rifled ammo they went to a NATO standerd

Only one Challenger2 has been fitted with a L-55 for testing.
The British Army still hasn't decided if we are even going to use smoothbore, because the rifled gun offers greater advantages(Increased range, accuracy and the HESH). The advantage of a smoothbore is a slightly faster muzzle velocity when firing sabots and NATO standard ammunition.

Smoothbores are only effective to 2500m when firing sabots.
Challenger1 scored the longest tank on tank kill ever in the Gulf1 with a kill at 5.1km. Smoothbores just cannot fire any ammunition out to this range.

Originally posted by GrOuNd_ZeRo
Good post Fritz, but nothing I didn't already know though.

As stated before, HESH rounds are the main reason the L-30 barrel is rifled so they can be delivered accurately.

Smoothbore barrels allow for more velocity since there is no friction to slow the round down while Rifled barrels afford more accuracy.

However the Challenger 2 has one of the most accurate guns out there, however it's FCS wasn't as impressive as some other modern tanks.

Are you joking??? Challenger2 probably has the best FCS in the world. Challenger2 is able to track and destroy choppers, and can hit the target the size of a football at 3km while moving at 30mph over rough terrain. The only other tank that can do this is the French leclerc...

reply to post by Taishyou


no, spinning rounds can not be guided onto its target, at least not easily;because its spinning produces massive gyrposcopic stability which makes it hard to change its trajectory once in flight. fins would'nt have any effect on a spinning round as the fins would be spinning too.

reply to post by Anonymous ATS


Not if the concrete bunker wall is thick it won't.

reply to post by Anonymous ATS


Absolutely true.

But when are we going to see Guided Munitions in combat ? and will they be applicable to Line of sight weapons like a tank - err *no*

IMHO, Guided munitions are a great attempt at making Field Artillery useful again (compared to laser air strikes / GPS missile strikes)

This has nothing to do with Tank combat, where the essentials are

1) Tactics on the ground
2) Fire control software
3) Accurate delivery of payload (rifleing helps)
4) Rate of Fire

Gaz

Rifling is no more accurate, and possibly less accurate for rounds that are aerodynamically stabilized and not spin-stabalized. The main one here is APFSDS rounds. They have to be fired with slip rings around the sabot, to keep it from spinning. Flechette and canister rounds are also made less accurate by rifling (increased dispersion). Flechette rounds might not be able to be fired from a rifled barrel at all. They aren't widely used though. Rifiling increases accuracy for spin-stabilized rounds like HE, HESH, HEAT, and HEAP. it also diminishes the effectiveness of HEAT rounds. HESH rounds cannot be used at all from smoothbore guns. Russians like to launch missiles out of their smoothbore guns.

The difference isn't much; smoothbore is a bit cheaper over the life of the gun, since it lasts longer, and rifled guns are still plenty accurate with APFSDS. Eventually, I'm sure Britian will join the rest of the world using smoothbore guns. the FCS and stabilization systems are more important for accuracy anyway.

APFSDS rounds from a smoothbore are more accurate at a longer range than conventional rounds because they have a higher velocity and are more aerodynamic, so they can travel farther and they lose less velocity than a standard round. Plus like what was said before, HESH rounds don't penetrate armor, they're designed to cause spalling, which is virtually nonexistant in modern tanks with anti-spall liners.

Originally posted by lonemaverick
APFSDS rounds from a smoothbore are more accurate at a longer range than conventional rounds because they have a higher velocity and are more aerodynamic, so they can travel farther and they lose less velocity than a standard round. Plus like what was said before, HESH rounds don't penetrate armor, they're designed to cause spalling, which is virtually nonexistant in modern tanks with anti-spall liners.

But you also forget to mention spall liners only protects the crew. Spall can and will damage electrics, hydraulics, optics etc... Not forgeting that being hit by one will also stall your vehicles engine...

Weapons will only destroy you in the end...if humanity got together no illuminati could win...even with all their weapons...give someone a hug...

reply to post by SKUNK2

Smoothbores are only effective to 2500m when firing sabots.

Where did you find that load of bullsh..? You are confusing the facts my friend. 2500m? First off the maximum effective range is generally listed at 3000-3500 m. Secondly "maximum effective range" is not an absolute term by any means it really just means the maximum distance a proficient gunner can engage and destroy targets with consistent accuracy. The compter on board the Abrams can create a shooting solution of up to 4000 meters but at that range human error becomes to big of a factor to allow the gun to be consistent. Around 2500 meters is the ideal distance where engagements for the Abrams would occur! This is a good range because most of the older vehices it has to worry about facing can't hit it (much less hurt it) at that range and it can hit them vey easily.

As for which is better rifled or smooth bore... well every major country that I can think of with the exception of the UK has a smooth bore on their MBT. The Abrams, Leopard, Leclarc, Merkava, T90, and even China's T99 all have smooth bore, and now it appears that even the UK is at least considering a smooth bore. These tanks are designed to be on the cutting edge of technolgy. The designers aren't sitting there saying "hey lets throw a smooth bore gun on this tank for grins" the experts obviously feel that the smoothbore has a distinct advantage over the rifled barrel. I would say that the major factor is that the smooth bore can easily fire a variety of ammunition and I would imagine it also has a considerably longer service life than the rifled barrel especially with the new ammunition and propellents being used.

reply to post by fritz



In looking for some info on smooth bore vs rifling I came across this thread and as well as a wiki entry which had some great info.

I found the barrel life figures shockingly short

With a caliber of 120 millimeters (4.7 in), and a caliber length of 44, Rheinmetall's L44 tank gun has a length of 5.28 meters (5.77 yd).[21] The gun's barrel weighs 1,190 kilograms (2,600 lb),[22] and on the M1 Abrams the gun mount weighs 3,317 kilograms (7,310 lb).[23], while the new barrel (L55) is 55 calibers long, increasing the length by 1.30 meters (1.42 yd). The bore evacuator and the gun's thermal sleeve, designed to regulate the temperature of the barrel, are fabricated out of glass-reinforced plastic, while the barrel has a chrome lining to increase barrel life.[3] Originally, the tank gun had a barrel life of anywhere between 400–500 rounds, but with recent advances in propellant technology the average barrel life has decreased to 260 rounds. In some cases, barrels have had to be replaced after only 50 fired projectiles

Source

Are that figure of 50 rounds real Even several hundred rounds seems like a very short life, but I'm no expert

Does anyone know if that figure is correct that a barrels lifespan can sometimes be as short as 50 rounds? If i'm not mistaken the M1 m1 Abrams carries 42 rounds, plus another in the chamber. Just seems like a low figure since they can probably expend that many rounds in just a few hours of fighting. I would imagine the sandbox is extra harsh on barrels when dust, sand, grit and debris get inside but only 50 rounds

If i am not completely wrong most sabot/armour piercing amunition has some kind of construction that makes them rotate when traveling through air, eliminating the need for rifled barrels to get spin for stability. They get the best of two worlds, smoothbore for velocity and spin due to projectile design creating the stability a rifled barrel.

See the "flights" on the projectile:

www.military.cz...

[edit on 13-1-2009 by Zykloner]

Originally posted by Zykloner
If i am not completely wrong most sabot/armour piercing amunition has some kind of construction that makes them rotate when traveling through air,...

Regrettably, you are completely wrong.

APFSDS (armour piercing fin stabilized discarding sabot) munitions are intended NOT to spin, that is why rifled cannons actually use an anti-spin collar when firing APFSDS (and HEAT as well).

I hope I can explain it right, the reason is that a spin only works stabilizing when there is a high enough leverage momentum. As the APFSDS rounds are essentially thin arrows you don´t get that leverage.

Those "flights" in the picture are part of the discarding sabot, the penetrator itself is thinner as you can see.

[edit on 13/1/2009 by Lonestar24]

reply to post by Lonestar24


Although fin stabilized projectiles do actually spin at low rate to even out any symmetrical imperfections. The spin will be given by the fins. For example if one of the fins had slightly more drag than the others it would cause it to turn ever so slightly in that direction, the low rate spin evens that out.