Does the 75mm/45 use same ammo as the 75mm/70?

[Mr. Johnson--]

So, do they fire the same round? How about the medium and long 88? Do they add more propellent?

[Paul Lakowski]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Mr. Johnson-<THC>-:

So, do they fire the same round? How about the medium and long 88? Do they add more propellent?<HR></BLOCKQUOTE>

The penetrators are longer and sharper while the charge is much larger...which is why they both penetrate more than the shorter versions of these guns.

[kipanderson]

Hi,

short answer is no, they do not use the same ammunition.

You guessed right, the 75L70 and the 88L71 both use a larger charge than their shorter barrelled cousins.

All the best,

Kip.

[kipanderson]

Paul, hi,

you said it all, we posted at the exact same time!

Good to see you are still out there.

All the best,

Kip.

[Dan Robertson]

The last four on the left are the rounds of interest.

The largest is the 88 L70, then the 88 L56 (tiger) then 75 L70 (Panther) 75 L48

as you can see they are very different sizes.

[Paul Lakowski]

<BLOCKQUOTE>quote:</font><HR>Originally posted by kipanderson:

Paul, hi,

you said it all, we posted at the exact same time!

Good to see you are still out there.

All the best,

Kip.<HR></BLOCKQUOTE>

Hi Kip , Good to talk to you again

I just came into alittle money,and awhile agoe we were discussing data on russian penetration from that 1000 page report from Bovington, do you remember?

Any way I still want them and I lost your Email so drop me a line and if you can still make copies I'd like to do that and send you a check!

What do ya think?

psl@interchange.ubc.ca

[rexford]

Panther 75mm and PzKpfw IVH both fire a 15# projectile, Panther shell has more charge so it flies faster.

[SenorBeef]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Paul Lakowski:

The penetrators are longer and sharper while the charge is much larger...which is why they both penetrate more than the shorter versions of these guns.<HR></BLOCKQUOTE>

Whats the reason for this? Why couldn't the pz4 use the round with the larger propellant to get more penetration?

Does it relate to needing a lower twist rate in the barrel due to length, or something similar?

[Michael Emrys]

Mostly it has to do with needing a more massive chamber and breech to contain the pressures of a larger and/or faster burning propellant. Sometimes the barrel needs reinforcement for the same reason. Also the barrel may need special coatings to withstand greater barrel wear associated with higher velocities.

Michael

[Username]

The picture shows a mix of AP and HE rounds I believe. The panther round is an AP.

There are two 75mm HE rounds, one for a L24 and one for a L43/L48 (both guns fired the same exact ammo). These are the fourth and fifth rounds from the left. The projectiles are the same but the casing is obviously different. The panther may or may not have used a similar projectile on its longer case also. This would certainly simplify production.

The AP weights of the L43/49/70 are very similar and I would assume that they shared an AP round also.

Lewis

[SenorBeef]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Michael emrys:

Mostly it has to do with needing a more massive chamber and breech to contain the pressures of a larger and/or faster burning propellant. Sometimes the barrel needs reinforcement for the same reason. Also the barrel may need special coatings to withstand greater barrel wear associated with higher velocities.

Michael<HR></BLOCKQUOTE>

Ah.. I thought it was simply a matter of the gas pushing the projectile faster and faster through a barrel, and so a longer barrel gives more acceleration time.

[Michael Emrys]

<BLOCKQUOTE>quote:</font><HR>Originally posted by SenorBeef:

Ah.. I thought it was simply a matter of the gas pushing the projectile faster and faster through a barrel, and so a longer barrel gives more acceleration time.<HR></BLOCKQUOTE>

Not exactly. Barrel lengths and propellant charges are designed to be mutually complementary. There is no point in putting more propellant in a round than the barrel can use, therefore merely lengthening the barrel is not likely to help any. The additional friction of the added length is apt to balance the added time for acceleration because the internal pressure within the barrel will have already begun to drop off.

Michael

[SenorBeef]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Michael emrys:

Not exactly. Barrel lengths and propellant charges are designed to be mutually complementary. There is no point in putting more propellant in a round than the barrel can use, therefore merely lengthening the barrel is not likely to help any. The additional friction of the added length is apt to balance the added time for acceleration because the internal pressure within the barrel will have already begun to drop off.

Michael<HR></BLOCKQUOTE>

Aha, so propellant charges are designed to start 'burning out' in relation to the length of time a round is in the barrel. That makes sense.

Edit: Clarity. That is to say, the length of the propellant burn is designed to be as long as the projectile's travel time in the barrel.

[ 05-25-2001: Message edited by: SenorBeef ]

[Paul Lakowski]

Yes if the propellant isn't matched to the barrel lenght it may peak to high and burst the barrel.

Lewis , close examination of the projectiles shows the penetrators are not the exactly the same both L-70 & L-71 feature slightly longer sharper penetrators which boost vertical penetration in relation to there mass, and at the expence of slanted penetration.....Although that might also be a consequence of the higher striking velocities.

[kipanderson]

Paul, hi,

I am on the case , I will email you.

All the best,

Kip.

[Username]

Actually, the two on the right (the 88L71 and 88 L56) seem to have slightly different shapes to the shells. I dont know if they are both HE but they dont appear to be AP.

[Matthew_Ridgeway]

<BLOCKQUOTE>quote:</font><HR>Actually, the two on the right (the 88L71 and 88 L56) seem to have slightly different shapes to the shells. I dont know if they are both HE but they dont appear to be AP.<HR></BLOCKQUOTE>

For someone who in the past has argued quite vehemently (or should I say obtusely) the subtleties of German Ordnance you sure are demonstrating a lack of knowledge here. The paint scheme on the projectiles is a dead give away as to what type of round the thing is.

[BsChoy]

I don't see anybody recognizing that a charge of the same size and weight will be faster out of a longer barrel than an identical round from a barrel of shorter length. Same rules apply for a standard rifle barrel...the more barrel you have the faster your round will fly

[BsChoy]

Originally posted by Paul Lakowski:

[QB]Yes if the propellant isn't matched to the barrel lenght it may peak to high and burst the barrel.

I have never heard of matching propellant to barrel length. In smaller terms if I shoot a 30-06 round which was the M-1 Garand round in WWII in a rifle with a 18in barrel, that same round is perfectly capable of being fired from a 30 inch barrel and it will leave at a much higher velocity. The same is applicable to field artillery. In WWI the paris gun had a 70 mile range and its barrel was something like 200 ft long. you could have fired that same round out of a 100 ft barrel without harm but much less range as velocity is depleted quicker.

[M Hofbauer]

A difficult question. Does a weapon that does not exist (KwK 7.5cm L/45) fire the same ammo as the KwK 7.5cm L/70....?

[ 05-26-2001: Message edited by: M Hofbauer ]

[Jeff Duquette]

Field Artillery will typically employ several different charges for the same weapon and same projectile. There are obvious reasons for this variation in propellant. Examples:

The US WWII 105mm M2A1 howitzer firing M1 HE would employ seven different charges resulting in seven different muzzle velocities ranging from 650 fps for charge-1 up to 1550 fps for charge-7. Same barrel.

German 105mm howitzer employed six different charges. When firing Panzergranate shell it employed two different charges…charge 5 and charge 6. Charge 5 (typical charge for the 105mm pz.gr.)...Muzzle velocity was 1295fps. A special Charge 6 pz.gr. round was also available...Muzzle velocity was 1525fps. Same barrel.

for charge 5 rnd

pz.gr. penetration of RHA @ 30 degrees @ 1000 meters for = 48mm

for special charge 6 rnd

pz.gr. penetration of RHA @ 30 degrees @ 1000 meters = 56mm

[Username]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Matthew_Ridgeway:

For someone who in the past has argued quite vehemently (or should I say obtusely) the subtleties of German Ordnance you sure are demonstrating a lack of knowledge here. The paint scheme on the projectiles is a dead give away as to what type of round the thing is. <HR></BLOCKQUOTE>

I was just going to ignore your BS but since this is (was) a good exchange of info; I will say that german 75mm ammo was mostly either black (AP) or green (HE, HEAT and smoke). How thats a dead giveaway remains to be explained by you.

The various olive greens had different lettering to ID what the shell was (if it wasnt HE sprg). So a green shell with black lettering "HL/B" is a hollow charge shell. If it had white "Nb" its a nebel smoke shell. Similarly, the black AP shells could have red bands (Pznr39) or a white "W" for tungsten (AP40). So the real dead giveaways are usually in the lettering (but the pic does not show that unfortunately).

Another dead giveaway is the silver fuze on the front of the shells. It signifys non-AP. Its a shell full of something (and so are you).

The shells in the pic show various shades of color that can be interpreted in several ways. The obviously different one is the yellow on the 88mm shell. So if you want to share with the group what kind of shell it is then why dont you? Why focus on me? I dont really care for your insipid rolling eyes snipe so screw off if you cant be a man.

Lewis

[Username]

<BLOCKQUOTE>quote:</font><HR>Originally posted by BsChoy:

I don't see anybody recognizing that a charge of the same size and weight will be faster out of a longer barrel than an identical round from a barrel of shorter length. Same rules apply for a standard rifle barrel...the more barrel you have the faster your round will fly<HR></BLOCKQUOTE>

This isnt true. The charge must match the barrel length. A good example is "The queens gun" story. Some queen wanted a long barreled pistol under the same assumption as you are making. But when they fired it (with a normal pistol cartridge), its range was shorter than a normal pistol.

The reality is that friction takes over once the charge ceases to accelerate the round. If the round reaches a point in the barrel where it just maintains a velocity, thats where you should probably cut off the barrel. So the real issue is acceleration. Thats the point of a gun. To accelerate a projectile to a velocity. I have read of a worn out hetzer that lopped off two lengths (to make a field modified L46 out of a L48!) because its grooves were shot at the end of the barrel. It was loosing velocity because of its longer barrel.

Since we are usually talking about rifled weapons (that impart spin), its very important that this friction be avoided. I would guess a smoothbore would be more forgiving.

When a rifled weapon is fired there is a small accel of the projectile because of the initial expansion of propellant. The projectile will then "dig" into the rifle grooves with its band and "stall". This generates the real spike of pressure in a gun. The pressure then drives the projectile down the barrel and increases the area in the barrel behind the projectile. This decreases the pressure continuosly till the projectile finally leaves the barrel.

An interesting fact is that the shell is spinning at a fantastic (to me) rate. Something like 20-30,000 RPMs. About 5-10 percent of the energy is put into spinning the shell and most of the rest is put into accelerating the projectile to its muzzle velocity (plus friction, etc). Supposedly the germans used proggressive rifling in 88s but I havent read too much about it. It might actually wear too quick but it would have some interesting pressure effects.

So having extra powder doesnt hurt (unless the gun blows up or wears out too quickly), having too little is bad also.

Hope this makes sense.

Lewis

[SenorBeef]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Username:

Hope this makes sense.

Lewis<HR></BLOCKQUOTE>

It does, actually. Thanks for the info.

[Matthew_Ridgeway]

<BLOCKQUOTE>quote:</font><HR>I was just going to ignore your BS but since this is (was) a good exchange of info; I will say that german 75mm ammo was mostly either black (AP) or green (HE, HEAT and smoke). How thats a dead giveaway remains to be explained by you.

The various olive greens had different lettering to ID what the shell was (if it wasnt HE sprg). So a green shell with black lettering "HL/B" is a hollow charge shell. If it had white "Nb" its a nebel smoke shell. Similarly, the black AP shells could have red bands (Pznr39) or a white "W" for tungsten (AP40). So the real dead giveaways are usually in the lettering (but the pic does not show that unfortunately).

Another dead giveaway is the silver fuze on the front of the shells. It signifys non-AP. Its a shell full of something (and so are you).

The shells in the pic show various shades of color that can be interpreted in several ways. The obviously different one is the yellow on the 88mm shell. So if you want to share with the group what kind of shell it is then why dont you? Why focus on me? I dont really care for your insipid rolling eyes snipe so screw off if you cant be a man.

Lewis<HR></BLOCKQUOTE>

yellow = HE

(TM E9-369A)