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question for armour lads... Dif in accuracy between smoothbore and rifled barrel

honestyrules

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Hi fellows,
me being an engineer ,i refer to you guys to answer my question. I red that the "stryker" has a smoothbore barrel. Is it any good? Could you guys fire the thing with as much accuracy as a leo would?

Thanks for your understanding!
 
I believe that the 105mm on the Mobile Gun System (MGS) version of the Stryker is rifled, but I haven't been on the vehicle.  I've read that it will be an M68 gun, which is the US version of the cannon found on the Leopard C2, but that might have been an error.  Regardless, with fin-stabilized ammunition for smoothbores I do not believe that it is much of an issue as far as accuracy goes.  The 120mm cannon on the M1 and Leopard II is smoothbore.  I'm sure that the gun will be accurate either way.

Some of the gunnery SMEs here might be able to go into more depth!

Cheers,

2B
 
At battle ranges the rifle and smoothbore have almost the same accurate  capablities firing apfsds rounds. Smoothbore cannons on the Leo2 and M1 to name a few have a larger warhead, just because of the 120mm vs the 105mm in riflled cannons.

However in non tank killing tasks the rifled tube has been seen to be a better cannon, this is due to a more stable projectile round in flight and has a greater range and accuratcy  when firing say Hesh or Heat.
mind you these differances are small, but never the less still there. The FCS and the ammo has more to do with accurate  round on target capablities than the tube itself.

Most New MBTs have a smoothbore now, due to a larger round being used, giving a bigger bang for the buck. The russian tanks use a smoothbore also, with another capability of launching a ATGM down the tube. The west in general has not had much luck in that department.

Hope this helps, Lance can add to this as well i would think.
 
You guys are great!

I really appreciate the opinions from experts (guys doing it). It answers my questions. Glad that you guys took the time to answer to this....


Delavan
 
The MGS will be using the rifled barrel, the exact same ones we have on the Leo C2 presently.  In fact, the barrels we have in stock will be the ones mounted, or kept in reserve.  A mix of L7A1/L7A3 and M68.

When firing ammunition with velocities in excess of 1,000 m/s, rounds are fin stabilized regardless of the barrel they are fired from.  The 105 mm rifled barrel fires fin stabilized APFSDS and HEAT rounds.  To keep the rifling from inducing spin to the round, which would degrade the fin performance somewhat, a "slip ring" is incorporated to the round.  The ring spins, the round doesn't (much).

The difference in accuracy with APFSDS is negligible, modern FCS and barrels are extremely accurate.  It doesn't really matter whether the barrel is smoothbore or rifled.

Slower rounds, such as HE type rounds, are spin stabilized.  This is because the round flies much slower, and the fins would have to be too large to stabilize the round in flight.  The 120/125 mm smoothbores do not fire HE type ammunitions because of this.  They are limited to APFSDS and HEAT ammunition.  The rifled barrels have the advantage of being able to fire smoke and HE type ammunition.

It boils down to what you want from the tank.  The MGS, from what I gather, will be used a lot in the Infantry support role, so we would want the capability of firing support ammunitions.  The Germans and Americans see tanks primarily for killing other armoured vehicles.  That's one of the reasons the British have been so reluctant to get rid of their 120mm rifled cannon, they want to be able to fire HE and smoke.

The BMP3 uses a rifled barrel, despite the Soviets not much liking rifled barrels.  That's because the HE-Frag round is very slow, and therefore requires spin stabilization.

Hope this helps.
 
Along the lines of what 12A and Lance Weibe are saying, I believe that the ability to fire HESH rounds (High Explosive Squash Head) will be a plus for the MGS.  The HESH round is well suited for supporting infantry attacks, and it also has good effects against buildings.  The Brits have stuck with the rifled barrel for their 120mm cannon and I believe that they still carry HESH.  The battles in the Western Desert are now old news, but I still think that tanks need to be able to fire some form of HE round to deal with non-armoured threats at long range.

The MGS will certainly have a lot of "gun" for its size.  Ammo load (and reloading), however, is another issue.

Cheers,

2B
 
Lance, and I'm not dis-ing ya.

Does the 125 not fire a He-Frag, and is not just a He round with more fragmention of a standard He round.
Talkin about there:

3VP-24 (3P-23 projectile)
Practice HE-FRAG round (same mass and behaviour as HE-FRAG, but inert)
3VOF-22 (3OF-19 projectile) (DOI 1962)
Charge: TNT
3VOF-36 (3OF-26 projectile) (DOI est.1970)
Charge: A-IX-2 (flegmatized RDX with aluminum) 3,400g

 
Different concept.  Because the BMP3 has a small turret ring, the 100mm He-Frag round has a muzzle velocity of less than 300 M/S, if memory serves.  Ergo, spin stabilized is the only way to go.

The 125 has a much faster muzzle velocity, right?
 
OK, found it.

The BMP3's 100mm gun fires the HE_frag at a muzzle velocity of 250M/sec, which is pretty darn slow. 

The 125mm launches the HE-Frag at 850M/sec.  Interestingly, 850M/sec is considered by many experts to be the low end of where fins are effective, the Soviets may be punishing the gun a little bit for this round to work, by upping the propellant charge.  I've read that the 2A46M/ D-81TM family of weapons only can fire 840 rounds of HE-Frag before being totally worn out and requiring replacing.  Compare this to the 8,000 HESH rounds the L7 cannon on the LeoC2 can fire before being replaced.  And our HESH round travels at 732 M/sec, not much of a difference for chemical rounds.
 
Lance Wiebe said:
Different concept.   Because the BMP3 has a small turret ring, the 100mm He-Frag round has a muzzle velocity of less than 300 M/S, if memory serves.   Ergo, spin stabilized is the only way to go.

The 125 has a much faster muzzle velocity, right?

The 125mm can't go much faster than the tank, I think you mean the round, never seen a tube fired down range, heheheheh

Yes I know what you ment to say.
 
12Alfa said:
The 125mm can't go much faster than the tank, I think you mean the round, never seen a tube fired down range, heheheheh

Yes I know what you ment to say.


What is it:
1-The 120/125 mm smoothbores do not fire HE type ammunitions
2.The 125mm launches the HE-Frag at 850M/sec

Your confusing me again, LOL
 
I'm curious.  I know that you're knowledgable about ballistics and armour.  We, on the board, were asked a fairly simple question, which was answered in a general manner.  I don't think the poster wanted to be quoted chapter and verse of "Theory of Armour Gunnery, Part one"  So, I'm curious about where you want to go with this "I'm cofused" stuff, when we both know that you're not confused at all.

You know, I know, and others on this board also know that the 125mm HE-Frag was in fact derived from a HEAT round, hence its higher than normal muzzle velocity.  We also know that it is not a superbly accurate round, as it is on the threshold of muzzle velocity for where fins are effective.

Do us all a favour, and post using your knowledge.  It seems to me to have slightly more benefit than using your knowlege to A: confuse, or B: stir the pot.
 
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