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Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

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FCS on early tanks   General Military Discussion

Started 22-Sep by smg762; 551 views.
smg762

From: smg762

22-Sep

Ive never grasped quite how tanks from, say, the cold war era, aimed their main gun. I presume they had a decently zoomed scope to see the target, was that all they had to go on? Or was there some radar assistance like on a ZSU.

Are todays tanks entirely automated in their aiming process? And how do they prescicely align the gun, given that the foe is 2 miles away, any error would mean the shot is 10metres wide or so..

How can the massively heavy gun make tiny adjustments?

Thanks for any info

  • Edited 22 September 2021 14:14  by  smg762
In reply toRe: msg 1
stancrist

From: stancrist

22-Sep

smg762 said:

Ive never grasped quite how tanks from, say, the cold war era, aimed their main gun. I presume they had a decently zoomed scope to see the target, was that all they had to go on? Or was there some radar assistance like on a ZSU.

Once upon a time I served in a M48 Patton tank crew, but that was almost half a century ago, so my memory of some details has faded.

As you surmise, the gunner had a high-magnification telescopic sight.  I think he also had a secondary sight, but I do not recall for sure.

No radar, LOL.  There was an optical rangefinder, and a mechanical ballistic computer that adjusted the sight for range and ammo type.

In reply toRe: msg 1
Red7272

From: Red7272

22-Sep

They basically had a stadia that listed all the range brackets for various ammo. but the APDS and APFSDS  were so flat shooting they really didn't need anything.  Optical range finders were also a thing. 

Those things on both sides of the turret are for the coincidence range finder. They were all replaced as soon as decently possible with laser range finders. 

The Brits had a ranging machinegun that had the same trajectory as the main gun to 2000 metres or so. The idea being they would fire the MG until it hit the target then switch to the main gun. In practice it saw little use and most people use them to set houses on fire with the tracer. 

Indian practical with the 20 pdr were to guess the range and then fire 3 rounds of APDS rapidly I at the guessed range 1 for 200 metres less and 1 for 200 metres more. The result was usually at least  1 hit and often 3 as the difference between the various rounds was about 25 cm

In reply toRe: msg 1
RovingPedant

From: RovingPedant

23-Sep

smg762 said...

Ive never grasped quite how tanks from, say, the cold war era, aimed their main gun. I presume they had a decently zoomed scope to see the target, was that all they had to go on? Or was there some radar assistance like on a ZSU.

Depends on when in the cold war era you are talking about. It starts at WW2 tech with a fairly low power telescope linked to or mounted on the gun cradle and ends up with decoupled sights. From stadiametric rangefinding (marks on the sighting telescope for how large typical targets would be at certain ranges) through optical rangefinders similar to those on battleships (but smaller) to laser rangefinder, plus machineguns for ranging, either matched to the main gun or with their trajectory marked on the sight graticle. In the latter case you’d follow tracer until on target, note the range where the strikes are observed, then adjust for the appropriate nature of main gun ammunition. This way you can accommodate different natures with substantially different trajectories, i.e. APDS and HESH.

smg762 said...

Are todays tanks entirely automated in their aiming process? And how do they prescicely align the gun, given that the foe is 2 miles away, any error would mean the shot is 10metres wide or so..

Modern main guns can be laid manually, but tend to have the gunner aim at and lase the target to get the range then the computer adjusts the azimuth and elevation of the gun to suit. The sight, being decoupled, stays centered on the target.

A slightly earlier system, with the sight still mechanically linked to the gun, starts the same but the computer projects an offset aiming mark into the sight and it is the task of the gunner to adjust the gun position to put the new mark on the target. This does then mean that the laser rangefinder is no longer aligned so you can’t update the range as easily.

For precision, the gun control equipment is just really precise. It is checked to ensure that it is aligned with the sights regularly by boresighting, though these days this is usually a telescope that slots into the muzzle rather than looking down the bore from the breech end. Most MBTs also have muzzle reference systems so they can keep track of where the gun is pointing as it heats up/cools down. Then there are other supporting systems to detect air temperature, air pressure, wind speed, own platform velocity, own platform level, humidity, facing direction (Coriolis is starting to be a thing) Target velocity can be obtained by changes in range and traverse rate.

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