Soviet heavy SP guns

[Mad Russian]

Having fired nothing larger then .45 cal never mind 152mm, I am gonna forage out of my comfort zone and say accuracy has nothing to do with muzzel velocity.

Muzzle velocity has everything to do with accuracy.

Take a ball thrown slow and with a large arc to it. Not very accurate. Take one thrown hard and fast. Much more accurate.

The faster it moves the straighter the line it can take to the target. That makes it much more accurate.

Good Hunting.

MR

[McIvan]

Put briefly, velocity means you have more leeway to get the range wrong and still hit, because the round hasn't dropped much, and the target has less time to move...perhaps in a direction you didn't expect....before the round arrives.

[PoorOldSpike]

... accuracy has nothing to do with muzzel velocity. At least in rifles, my short barreled 45-70 gov't is extremely accurate even though the bullet is only travelling about 1,300 feet/second. They used this cal. to hunt bison at 1,000 yards and more with iron sights, and at that range a bison is a rather small target. My .338 cal. in a long barrel is also accurate travelling at 2,300 feet per second, I cannot say which one is more accurate.

Yes a low vel is fine if you've got all the time in the world to estimate the range,calculate the wind speed and direction, adjust the sights then fire against a stationary target, (remember the assassin in Day of the Jackal carefully zeroing in his sights by popping at a pumpkin?)
But in tank battles there's no time for that.
For example suppose a Pz IV armed with a long 75mm L/43 (740 mps) spots a moving tank at 1000 metres, the gunner simply lays his crosshairs on it and fires, and the shot zips in a fast horizontal line with negligible gravity drop and probably hits.
But if the gun was a short L/24 (385 mps), the gunner could not simply lay his sights on the target and fire, he'd have to first estimate the range and elevate the gun to fire at a point just above and in front of the moving target, hoping that by the time the shell arrived in its slow arcing trajectory the target would still be there.

By contrast, what a luxury for tank gunners to be able to simply lay their crosshairs on the target and fire! Only high-vel guns allow them to do that.
CM models this pretty nicely, that's why short low-vel guns miss like crazy unless the targets at short range.

[Nort]

[PoorOldSpike]

In fact I remember reading a question in a PC Games mag a few years ago where somebody asked about the Close Combat game - "why is the Stug 105 so good in the game? It never misses and kills most enemy tanks it hits, so why are the Tiger and Panther more famous?"
I don't know if anybody wrote in with the answer,I know it myself, but does anybody care to have a shot at answering it in this thread?

(PS - I had Close Combat myself for a while but never felt comfortable with it, the 2D map wasn't my cup of tea, and I never liked the RTS system..)

[kineas]

Flight time is everything when you are aiming at moving targets. And is a major factor for stationary targets too.

[Ratzki]

PoorOldSpike

Yes a low vel is fine if you've got all the time in the world to estimate the range,calculate the wind speed and direction, adjust the sights then fire against a stationary target, (remember the assassin in Day of the Jackal carefully zeroing in his sights by popping at a pumpkin?)
But in tank battles there's no time for that.
For example suppose a Pz IV armed with a long 75mm L/43 (740 mps) spots a moving tank at 1000 metres, the gunner simply lays his crosshairs on it and fires, and the shot zips in a fast horizontal line with negligible gravity drop and probably hits.
But if the gun was a short L/24 (385 mps), the gunner could not simply lay his sights on the target and fire, he'd have to first estimate the range and elevate the gun to fire at a point just above and in front of the moving target, hoping that by the time the shell arrived in its slow arcing trajectory the target would still be there.

By contrast, what a luxury for tank gunners to be able to simply lay their crosshairs on the target and fire! Only high-vel guns allow them to do that.

The gunner using a high vel. round would have to do just as many calculations as he would firing a low velocity round, but the deviation from aiming point to contact point would not vary as much. Even a high velocity round moves in an arc from the end of the barrel to the intended target, it is not a straight line. Sights would be zeroed in at what would be the effective range of the gun, then as the round exits the barrel it would be under the aim point by what could be several feet for a specified distance before crossing the aim point for the first time to then being above the aim point by as much as severl feet again, to finally as energy is bled off rapidly crossing the aim point again on the way down to earth. The trajectory is not as pronounced as with a low vel. round, but still exists. Within effective range of each gun there would be little to compare with hit chances. A high velocity gun would be more accurate at it's extreme range the would a low velocity gun at the same range, but at a shorter distance within the low vel. gun's effective range there would be no difference, and the high vel. may be at a disadvantage in some instances dependant on it's on round's arc when fired.

[Mad Russian]

PoorOldSpike

Yes a low vel is fine if you've got all the time in the world to estimate the range,calculate the wind speed and direction, adjust the sights then fire against a stationary target, (remember the assassin in Day of the Jackal carefully zeroing in his sights by popping at a pumpkin?)
But in tank battles there's no time for that.
For example suppose a Pz IV armed with a long 75mm L/43 (740 mps) spots a moving tank at 1000 metres, the gunner simply lays his crosshairs on it and fires, and the shot zips in a fast horizontal line with negligible gravity drop and probably hits.
But if the gun was a short L/24 (385 mps), the gunner could not simply lay his sights on the target and fire, he'd have to first estimate the range and elevate the gun to fire at a point just above and in front of the moving target, hoping that by the time the shell arrived in its slow arcing trajectory the target would still be there.

By contrast, what a luxury for tank gunners to be able to simply lay their crosshairs on the target and fire! Only high-vel guns allow them to do that.

The gunner using a high vel. round would have to do just as many calculations as he would firing a low velocity round, but the deviation from aiming point to contact point would not vary as much. Even a high velocity round moves in an arc from the end of the barrel to the intended target, it is not a straight line. Sights would be zeroed in at what would be the effective range of the gun, then as the round exits the barrel it would be under the aim point by what could be several feet for a specified distance before crossing the aim point for the first time to then being above the aim point by as much as severl feet again, to finally as energy is bled off rapidly crossing the aim point again on the way down to earth. The trajectory is not as pronounced as with a low vel. round, but still exists. Within effective range of each gun there would be little to compare with hit chances. A high velocity gun would be more accurate at it's extreme range the would a low velocity gun at the same range, but at a shorter distance within the low vel. gun's effective range there would be no difference, and the high vel. may be at a disadvantage in some instances dependant on it's on round's arc when fired.

Yes, but doesn't the higher the velocity flatten out the trajectory? So the higher the velocity the flatter the trajectory the easier it is to obtain a hit.

Good Hunting.

MR

[Ratzki]

Yes, and no. First the yes, a higher velocity does flatten out trajectory, but you have to factor in the maximum penetration potential range of each gun. If you have a gun designed to be in it's maximum penetration potential range at 300m-1000m, then all targets within that range will be easier to hit due to the low trajectory of the shell at that range, not the velocity, and the sights will be zeroed in at this range. Now for the no, start shooting at longer and longer ranges and the trajectory increases as the penetration potential decreases. Plus, the trajectory curve is not perfect, it is flatter close to the muzzle and has a steep downward curve as the shell passes by the maximum penetration potential range. Also, high velocity usually means lighter round weight, and lighter rounds are influenced more by external factors such as wind ect. A low velocity gun might not have the long range penetration potential that a high velocity gun has, but the same rules apply. It's maximum penetration potential range might be 50m-200m with an AP round. At this range it's trajectory could be as flat as the high velocity gun is at greater range. If the sights are zeroed in at this range, then it too can be very accurate.
I handload as well and as Skeld mentioned back a bit, there is a whole lot more going on here then simple speed equals better hit chances. I think the reason high velocity guns hit more often is they can kill effectively farther away, so get better optical sights.

[Mad Russian]

Yes, and no. First the yes, a higher velocity does flatten out trajectory, but you have to factor in the maximum penetration potential range of each gun. If you have a gun designed to be in it's maximum penetration potential range at 300m-1000m, then all targets within that range will be easier to hit due to the low trajectory of the shell at that range, not the velocity, and the sights will be zeroed in at this range. Now for the no, start shooting at longer and longer ranges and the trajectory increases as the penetration potential decreases. Plus, the trajectory curve is not perfect, it is flatter close to the muzzle and has a steep downward curve as the shell passes by the maximum penetration potential range. Also, high velocity usually means lighter round weight, and lighter rounds are influenced more by external factors such as wind ect. A low velocity gun might not have the long range penetration potential that a high velocity gun has, but the same rules apply. It's maximum penetration potential range might be 50m-200m with an AP round. At this range it's trajectory could be as flat as the high velocity gun is at greater range. If the sights are zeroed in at this range, then it too can be very accurate.
I handload as well and as Skeld mentioned back a bit, there is a whole lot more going on here then simple speed equals better hit chances. I think the reason high velocity guns hit more often is they can kill effectively farther away, so get better optical sights.

Okay then...moving over to something I know a bit more about....my grandfather was a gunsmith. He used a 30-06 to hunt with. Which in his day was pretty standard. The gun I prefer is the 270 Wincester.

To compare the 30-06 which had a larger bullet to the 270 Winchester which had the smaller bullet is close to what we have here in the larger scale I think. It's about all the balistics I know.

Same scope. Different rifle. Different results.

I think the Germans used the same optics on their tanks but I"ll have to check that since they could easily have had different optics for each and every tank.

But here's what I know. The 30-06 round doesn't drop coming out of the gun barrel but rises. The 270 round doesn't rise as much and is faster.

In a purely velocity discussion. Not taking into account anything else.

The faster the round the more accurate at longer distances. The penetrating factors of the round increase with speed. The faster it's going the more energy it is carrying when it hits compared to a slower round. Not talking HEAP here but just Solid Shot AP.

The less rise you have out of the end of the barrel, the straighter the trajectory, the more accuracy you have at longer ranges. With my rifle comparison what does that mean?

Both rifles sighted in at 150 yards. The 270 with the lighter bullet and faster velocity hits a mark at 300 yards at say 1 inch below the aiming mark. The 30-06 hits it an 1 1/2 to 2 inches below. At 400 yards the 270 hits the mark 2 inches below the aiming point and the 30-06 as much as 3 or 4 inches below. This can be the difference in killing an animal or wounding one.

The same holds true of larger weapons to my knowledge. All things equal higher velocity is more forgiving of the aiming point. You can shoot farther with less adjustments made to the original aiming point.

Good Hunting.

MR