Ian McCollum on the PTRD 41

Uncle_Duke

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That was a very good video.
Hate to have to carry that beast!
Come on! Even with all its ammunition, it's only 1PP! You can manage it, comrade!

In all seriousness, I wouldn't be too much a fan of carrying it around either. And I can't imagine trying to use something like that in Stalingrad, or any other street fighting, for that matter.
 

Bob Walters

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Actually, If it were set up on an upper floor of a building as an ambush it would have been quite effective against most of the tanks at Stalingrad.
 

Uncle_Duke

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Actually, If it were set up on an upper floor of a building as an ambush it would have been quite effective against most of the tanks at Stalingrad.
It's not an issue of effectiveness-- I don't doubt that a hit on the top side of a tank would wreck somebody's day. My concern was more one of being able to find an effective firing position in the first place-- a ~2m long weapon like the PTRD or PTRS isn't going to be particularly easy to emplace, especially if you're looking for a location with good coverage at close ranges.
 

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A bazooka isn't much smaller, although it is probably lighter. The M9A1 Bazooka was 61" long, about a foot shorter. Plus you had to worry about backblast.

JR
 

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It's not an issue of effectiveness-- I don't doubt that a hit on the top side of a tank would wreck somebody's day. My concern was more one of being able to find an effective firing position in the first place-- a ~2m long weapon like the PTRD or PTRS isn't going to be particularly easy to emplace, especially if you're looking for a location with good coverage at close ranges.
That's what bipods and sand bags are for, hunt up a table knock out a rat hole or find a window and you're sitting sweet!:nod:

EDIT: We're infantry, we're heart breakers & life takers, our business is is in breaking things and being expedient in doing so-hey it's what we do!
 
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It's a little confusing to me that the UK and Germans mostly retired their anti-tank rifles by mid-war, yet nowadays most armies seem to value having anti-material rifles (essentially the same as WWII ATRs.) Were they wrong then? Are they wrong now? Or are modern battlefield conditions just that different? I can believe that there are a lot more softskin motorized vehicular targets on a modern battlefield, but it doesn't seem like there'd be that big a difference in the likelihood of encountering a light AFV. And being able to shoot an enemy through light building construction or other light cover would seem to always have value.
 

Paul M. Weir

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Interesting angle on ATR, not something I have thought about.

Excuse me for going through the history, but I'm thinking aloud about the question. In '39-'40 the ATR had some chance against the early war tin cans, many with just 15mm of armour. While the various armies had small numbers of proper AT guns, the quantities were low, you might see 2-6 per regiment/brigade. The exception was the Germans who had a company of 12 per infantry regiment and an additional battalion (36) per division. So for most infantry of that period an ATR would be the only AT weapon that they could see.

In the meantime various nations were developing SCW/HEAT hand and rifle grenades, the Germans indeed cut down some of their ATR and fitted them with grenade discharger cups. By '43 the Germans had the Puppchen (8.8cm Raketenwerfer 43) and the US the Bazooka. The Germans used a modified Puppchen round in a Bazooka type tube to give the Panzershreck and the British developed their PIAT. Those and the German Panzerfaust were now capable of dealing with later tanks, albeit at short and risky range. These were needed in large numbers, so why continue to produce heavy and expensive ATR when there were better weapons available and used manufacturing capability. The various SCW could deal with anything an ATR could and were in competition for manufacturing capacity during a high intensity war.

I'm ignoring the assorted 20mm ATR (Lathi, Type 97 and various Solothurns) as these were really too heavy and expensive to be regarded as infantry weapons. Indeed they had inferior penetration than the Soviet 14.5mm PTRD/PTRS. Except very early in the war, just too much gun for too little effect.

So why the resurgence of the anti-material rifle/ATR? The LAW type disposable or RPG-7 type reusable are much better able to dish out than an ATR type weapon against armour. A .50"/12.7mm/14.5mm MG can chew through brickwork just as well. I suspect it's the convergence of peacetime production capability and a wish for something less obvious and destructive for anti-insurgency warfare. In a full on war and you receive "sniper" fire, you just drop a battery of 155mm/122mm rounds on the miscreant's heads. A civilian vehicle is spotted, you put a 120mm HEAT round in it. Not a good idea if you are supposed to be protecting the populace from guerillas. So a 12.7mm round in the engine block might be a better solution. A 12.7mm round or two looks better than razing a city block over one sniper.

The post war convergence of the standard rifle round to the mid-5mm sizes gave many advantages but did reduce both range and common material penetration. Most armies retained WW2 type calibres for sniper rifles and if you have to have small numbers of an "odd" round, bigger might be better for such specialist tasks?

If a full scale war did break out, I doubt that anti-material rifles would have much space in the supply chain. They are surgical weapons and ideal for the currently most common type of combat, the insurgency war where discretion of force is a decided overall political advantage.

Now I may be misreading the military procurement mindset, but I think a combination of warfare type, production/supply capacity and the widespread adoption of the 5.?mm rounds meant that a niche for such weapons opened up. That's my best guess. I'd be interested in other's opinions or slant as it's not something much discussed as a general trend.

EDIT: I almost forgot, the rounds are much cheaper than the alternatives. ;)
 
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Thanks Paul - I quite enjoy it when you 'go through the history'. After I posted I started to wonder about the possible role of anti-insurgency warfare and the reduced punch of modern rifles as well - not just in caliber but also I think in velocity? Don't even nominally 30 caliber Kalashnikov type assault rifles have shorter, less powerful rounds than their WW II analogs? I'm not really a gun guy so I could be wrong about this, but it seems like firing a burst of full auto with the type of rounds used in single shot bolt action rifles would be a challenge.

I also wonder about the casualty averse nature of the "modern" sides in asymmetric warfare - you're rather safer firing at a 'technical', improvised bunker, etc. from anti-material rifle range than from LAW ranges. Might be a factor?
 

Paul M. Weir

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Don't even nominally 30 caliber Kalashnikov type assault rifles have shorter, less powerful rounds than their WW II analogs? I'm not really a gun guy so I could be wrong about this, but it seems like firing a burst of full auto with the type of rounds used in single shot bolt action rifles would be a challenge.

I also wonder about the casualty averse nature of the "modern" sides in asymmetric warfare - you're rather safer firing at a 'technical', improvised bunker, etc. from anti-material rifle range than from LAW ranges. Might be a factor?
Yup, BarkingMonkey, the AK in 7.62x39mm has a lower muzzle velocity (715 m/s = 2,350 ft/s) than their Tsarist era 7.62x54mmR (840 m/s = 2,755 ft/s), see physics section at end. You would need a strong man indeed to control full power power cartridges in full auto.

Yeah, you would have a range advantage with a rifle over a LAW but that could just as well be said about a tank gun or IFV auto cannon or even an artillery strike. The anti-material rifle round is more surgical, cheaper and might generate less political blowback from the local residents. Less enraged locals might save you further casualties later on.

While I have a better than knowledge than average person in an Irish street (average US street might be a different matter, bloody US gun nuts :p) about arms, my knowledge is from (2nd hand) battle reports and simple physics. So I might as well outline what some of the above figures mean.

Terminology:
A cartridge is often specified like the above "7.62x54mmR". A round is both the cartridge (which contains the propellant) and bullet. The 1st number obviously the calibre, the 2nd number is the cartridge/casing length, including the overlapping bit that holds the bullet in place. There are other measurements like the angle of the bottleneck in high power cartridges that allow the round to seat properly in the chamber that manufacturers have to meet, but something like 7.62x39mm is usually enough to uniquely specify the round. The 2nd, cartridge length, gives a good idea of the powder amount and the relative power of the round.

You will sometimes see "R", "B" or "SR" after the 2 values. All cartridges have some way that allows an extractor claw to grip one side of the cartridge when after firing the bolt opens to cause the cartridge to be flipped sideways (or up or down), whether manual bolt or (semi-) automatic. No letter means a depressed ring/trough near the base for the claw to slip into, "R" or Rimmed means the base forms a raised ring that the claw catches, "SR" or Semi Rimmed means a bit of both, a depressed ring with a small raised rim at the base and "B" means Belted which involves a short but fatter section of a cartridge just forward of the extractor rim or recessed ring. Belting has more to do with reinforcing the cartridge and provide sealing against gas escape than extraction and belted rounds typically have rather hairy power.

So the 7.62x54mmR is a bottleneck cartridge (the body is fatter than the bullet) but has an protruding Rim at the base for extraction (like many common .22" varmint rounds). Rimmed rounds are fine for small magazines and bolt actions but can cause problems in large magazines and auto weapons. Compare the Czech ZB-26 (7.92x56mm) straight magazine with it's British .303" variant, the Bren, with its curved magazine for 7.7x56mmR. The rims can interfere with each other causing feed problems.

History:
Between WW1 and WW2 there was a lot of discussion about rifle rounds. From the introduction of rifles in the 1850s+ the idea was to get maximum velocity and range. That was great for colonial warfare and indeed the Boers reinforced that idea with the British when they often out-ranged them (1000m+). However the experience from WW1 showed in high intensity warfare that battle ranges were in the order of 200-400m, often much, much less. In addition mass conscript armies were mostly incapable of achieving accuracy much beyond moderate ranges. The heavy recoil didn't help either.

So between the wars there was a lot of talk of replacing the old full power rifle rounds with somewhat less powerful and more manageable rounds, especially in light automatic weapons. None of those designs got anywhere because there were enormous stocks of rifles, MGs and ammunition and most of the world was pretty well broke after WW1 and the Great Depression. The Germans in WW2 depended upon large numbers of auto weapons and wished to replace bolt rifles with semi and ideally full auto weapons. The pistol cartridges used in SMG were just too weak and normal rifle rounds caused sidearms to climb, dive or go sideways off target in auto mode. So they developed a 7.92x33mm Kurz (= Short) intermediate round for the StG 44, to replace their 7.92x56mm standard rifle round. There is some debate as to whether the Soviet 76.2x39mm was developed in parallel or based off the German 7.92x33mm, but the Soviets were just as good as the Germans in arms design and the idea of an intermediate round had been around for decades. Basically the same weight but lower velocity bullet.

Meanwhile in NATO the US insisted on retaining a full power rifle round that emerged as the NATO 7.62x51mm, somewhat based upon the old .30-06 (7.62x63mm) round (more powerful modern propellants, less volume needed). Eventually they did go intermediate but with a smaller calibre 5.56x45mm. That resulted in a much lighter bullet but kept the velocity high, indeed MV was as good as if not higher than the WW1 era 7.62/7.92mm/.303" cartridges. The Soviets eventually went that way with their 5.45x39mm cartridge.

Light but high velocity bullets give nice flat trajectories out to 300-400m but loose velocity at range and are more easily deflected by light cover. I have read in a few places that there is some talk of going to something more like 6.5mm with muzzle velocities between the 5.56x45mm and the 7.62x39mm due to experiences in Afghanistan. That would be a quite ironic full circle as the world's first Assault Rifle was the Federov Avtomat, a Russian 1915 design using the (Japanese) Ariska 6.5x50mmSR round with a MV of 2,145 ft/s, 654 m/s.

Physics:
Now for a little physics. Bullet energy is (M*V^2)/2 where M is mass and V is velocity. So doubling the velocity gives 4 times the energy and the destructive effect on the receiving end. That doubling of velocity means the flight time is halved and the distance the bullet falls under gravity is quartered (drop = (g*T^2)/2 where g = earth's gravity = 9.81/M/s^2 and T is flight time). However that doubling of velocity doubles the drag force on the bullet and lighter bullets will slow quicker than heavy bullets. Recoil impulse is simpler at roughly M*V. So halving the bullet weight but doubling the MV gives the same recoil but delivers twice the energy and needs twice the propellant. That's the simplified physics but you can see there are trade offs between high MV light bullets and slower but heavier bullets and these trade offs keep designers in food, lodgings and drink.

Excuse the length but that should give you a reasonably solid basis for further exploration of the subject whether in books, Wiki or Google and may fill out other's gaps in their knowledge. Sometimes having a grasp of why some armies developed something is as important as what and how.

There are a fair few service people here in GS who will be much better able to educate you on the strengths and weakness of the various weapons that they have used, but you should have a starting point.

EDIT: I forgot one quite important advantage of intermediate rounds, whether high MV, light bullet or medium MV, heavy bullet; They are smaller and lighter so more can be carried by the soldier and shipping is easier. Duh!
 
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NUTTERNAME

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The Soviet 14.5 mm ATRs were a good enough threat to the Germans, that they developed the 'skirt' (schurzen) armor for the various tanks and assault guns. The physics by which this works is that these WWII type tungsten rounds were very brittle, and would shatter when they went through most metals. When they did penetrate the actual armor of AFV, they would shatter and spray the the interior, not always with great effect. The Germans tested these skirts and found they disrupted the penetrators effectively. They not only would shatter the antitank rounds, but also disrupt the flight path so they were not travelling point first. Post war tungsten carbide rounds were sheathed in a hard steel to protect against this effect BTW. The skirt armor was also meant to defeat HE rounds fired on super-quick fuse against the tracks/bogies. It just so happened later to also have some benefit from bazookas.

The ATR had some great advantages just from it's need to be used at short ranges (against armor). Firstly, it was inherently accurate due to it's high velocity and fairly large round. The sights were close to the line of the weapon, and aiming at specific areas made it a nuisance weapon. Firing at cupulas, vision ports, gun barrels, etc., had a physical and psychological advantage. Integrating them into Pak-Fronts, and having them used against tanks entering into a cross-fire of ATR and ATG made for a bad day for most German armor up till mid-1943. I suppose the Soviets might have stopped manufacture before the end of WWII. They did this with other weapons, I believe the 82 mm mortar, not because of not needing them, but the Logistics guys figured out that they had made enough already.

The Soviets did have steel round as well as tungsten rounds, and this ammunition was used as a basis for the Soviet 14.5 mm machine gun. So, it is certainly a anti-material weapon but a brute to carry. The ammunition is less bulky than rockets, but overall, it is an expensive piece of equipment requiring great machining. I have seen them used in the recent Ukraine war as additional weapons for dug-in troops, and it has quite a firing signature. It could be used at great ranges against buildings and would go through most structures. A poor man's anti-material rifle.

I would think street fighting (or urban fighting), would be an excellent use of the weapon. I once picked up a German antitank rifle in a museum and it is a heavy piece of ordnance to hump around.

Edit: Good video, just because they don't shout out "Death to Bitch-Snitches...", actually they are not using full loads or tungsten rounds (of course).

 
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NUTTERNAME

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One of the reasons for the resurgence of these anti-material rifles is the great ranges and terrain heights encountered in mountainous warfare. Having an enemy at a higher elevation puts friendlies at a distinct disadvantage. Even with matched weapons, the person holding the high ground out-ranges you and generally has the easier shot (less super-elevation). One can't call up a Abrams with a 120mm in the hills of Afghanistan. . High ground rules, and shooting the enemy off the other high ground is sound SOP. Range is always a selling point, and I believe there is an instance in the Korean war of a US sniper using a 14.5 mm weapon on a tripod type mount as a sniping weapon?

I will probably google it, but I wouldn't be surprised if there isn't a civilian type weapon based on the 14.5 mm. Ammunition is probably available cheaply, or cheaper than 50 cal.

http://www.russianammo.org/Russian_Ammunition_Page_145mm.html

The Soviet WWII ATR had unusually long barrels. They would not sacrifice that much velocity with a shorter barrel. Many people equate barrel length with high velocity. It really is powder-weight predominantly, with barrel length being dictated by that parameter.
 

Paul M. Weir

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I agree that powder to projectile weight is the best guide.

However a long barrel does many things:
It permits a longer time to accelerate the projectile
That in turn allows the propellant to burn more completely
The longer time allows the use of a slower burning powder, keeping peak pressure within safe limits
More complete combustion means less flash and blast
A longer barrel adds weight and makes the weapon more controllable against the recoil impulse
A longer sight line aids accuracy.

The British introduced a shortened version of their Boys ATR (Mk II) for paratroopers in '42/'43-ish and while the Boys was regarded as a bit useless and a bit of a pain, the shortened one was regarded as a right nasty bastard.
 
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NUTTERNAME

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However a long barrel does many things:
It permits a longer time to accelerate the projectile
That in turn allows the propellant to burn more completely
The longer time allows the use of a slower burning powder, keeping peak pressure within safe limits
More complete combustion means less flash and blast
Well, perhaps true for most early 1800's cannons, but not really applicable to modern arms. Most modern weapons from WWI on use 'smokeless' propellants. These propellants basically turn solids into gases. And the gas makes pressure. This is what makes the projectiles accelerate down the barrel. Due to the nature of the chemistry of these propellants, they will create the greatest pressure very early in the projectile's travel. As the projectile first engages the rifling, forming a seal, the projectile is being pushed by the great pressures generated, but since it is actually moving, and creating a larger cylindrical space behind it, pressure drops. Consequently, the pressure will decrease as the propellant has been fully changed from a solid to a gas, and the cylindrical pressure vessel behind the projectile has increased. The greatest G forces are experienced (both translational and rotational) in the half barrel length or less once fired. The actual velocity gains from acceleration towards the end of the barrell are much smaller.

As an example, take the German P-38 pistol, and the German MP-40 SMG. Both fire the same ammunition, but the SMG has a longer barrel. I believe it is actually twice the length. The velocities are, respectively, 365 M/s and 400 M/s. It would be interesting to know the decibel level of each, I doubt that either has a great 'flash', and not sure what you mean by 'blast'?

A longer barrel adds weight and makes the weapon more controllable against the recoil impulse. A longer sight line aids accuracy.
I would say a longer barrel can aid accuracy, but so does a precision barrel or ammunition. There are schools of thought. If one doesn't care about weight, just make a thicker barrel, it will aid in over-heating.

Interesting info regarding Polish ATR. Especially the projectile.

http://military.wikia.com/wiki/Wz._35_anti-tank_rifle
 

Paul M. Weir

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Smokeless powders are not truly smokeless, I have seen the smoke and residue and cleaned it out. Nitrocellulose does not have enough oxygen to fully oxidise. Nitrocellulose is a polymer but if you took 2 base units the formula would be 12 x C, 14 x H, 6 x N and 22 x O. The 12 C and 14 H require (12x4 + 14x1) /2 = 62/2 = 31 oxygen atoms yet there are only 22 oxygen atoms. Some or indeed most of that deficit is made up by the partial oxidisation of carbon to carbon monoxide (CO) rather than carbon dioxide (CO2). However in practice there is some carbon produced.

The old black powder was a mix of potassium nitrate, sulphur and charcoal (mainly carbon). Apart from reducing the ignition temperature, the sulphur combines with the potassium part to give potassium sulphides and sulphates, reducing the amount of carbon dioxide that combines with potassium to give potassium carbonate. Carbon dioxide is one of the gases that propel the round. The black powder "smoke" is a mix of fine solid potassium sulphate, carbonate and sulphide grains (~55% by weight). https://en.wikipedia.org/wiki/Gunpowder#Chemical_reaction

So while "smokeless powders" do not produce just gasses, they produce far, far less solids (smoke) than gunpowder.

The 'flame front' speed of a smokeless powder is roughly 7-8,000m/s. Propellant powders have their grains sized to suit the application. You often need some tiny delay (as the flame burns through the depth of the grain) to limit the build up of pressure while the projectile is just starting to move. In small calibre, low power weapons the powder grains can be quite small, flat or thin as the weapon can be sufficiently over-engineered without a great weight penalty (eg a .22" varmint rifle). In higher powered weapons the grains or rods should be made thicker so to slightly delay complete combustion until the projectile has moved a bit (increasing the effective chamber volume). That will keep peak pressure within limits while continuing to providing additional pressure gasses that compensate for the increased volume.

Now as the projectile travels down the barrel and the last of the propellant has burnt the pressure drops. As pressure drops so does temperature. That is not just from contact with the cooler barrel but simply due to pressure drop. Finally the projectile leaves the barrel and the combustion gasses now mix with air. The above nitrocellulose has an oxygen deficit and among the by-products are carbon monoxide with some very fine carbon. If the gas temperature has not dropped enough then the carbon monoxide and the carbon can burn giving muzzle flash and blast, distinct from the initial propellant burn. That turbulent mix of incompletely oxidized gasses and air is more omni-directional when it ignites than the the initial outpouring of the propellant gasses. That can kick up dust and/or produce some flash dazzle (especially at night).

A longer barrel not only can absorb more heat but it's greater internal volume cools the gasses by adiabatic cooling. That can reduce the chances or degree of muzzle flash and secondary muzzle blast.
 

NUTTERNAME

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Hence my use of the parenthetical 'smokeless powder'....

Well, perhaps true for most early 1800's cannons, but not really applicable to modern arms. Most modern weapons from WWI on use 'smokeless' propellants.
I guess you want to talk past each others points...? Hilary?
 

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My main point was concerning flash and blast and how a longer barrel can reduce those. Most pistols and SMG don't have too much of a problem with either, but moving up to rifle power or beyond can.

My late father and I fired both a .22" LR (Long Rifle) and a .22" Magnum. The latter, despite the name, is just a souped-up .22" rimfire, the two having MV of ~1300 and ~2000 ft/s respectively, only the later barely coming into military specs range (AK 47 ~ 2350 ft/s). The Magnum did produce a considerable additional "blast" sound, distinct from the LR "crack" and produced some flash unlike the LR. So I can only imagine what a 14.5mm with a MV of 3500 ft/s would produce, even with its very long barrel. Imagine further what the result would be with a shorter barrel!

I will readily admit that I do go on and on, but my paragraphs on black and smokeless powders were to provide background for those who are not familiar with the details of firearms or the chemistry and physics involved. Some will find that boring, while others seem to like the extra detail or history. I, in my long winded way, try to provide as much information to any readers so that they can understand the underlying principals involved and when faced with similar situations or questions can make a more educated assessment. Not just the answer is X but why is it X. Any factual response to a post should illuminate anyone who reads it not just the original poster.

In the years posting here I have come across many topics that triggered my child like curiosity. I have had to read up on many topics and obscure subjects. As a result I have learned a lot and got much joy from same. I assume the people here are intelligent and curious and hope that what I post will in turn trigger their own curiosity and investigations and hopefully they in turn will get similar satisfaction and joy from their discoveries. I try and give "extra value" for everyone here.
 
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