Gunfreak | 22 Mar 2018 12:47 p.m. PST |
Watched the movie on Monday. Last time i watched it, I knew nothing of shermans. Now i know mabye 3% about them. And i noticed all the shermans had long barrels with muzzlbreak. Are they all 17pdr or all 72mm. Wouldn't it be more correct to have a mix of 75/17pdr? |
shaun from s and s models | 22 Mar 2018 12:52 p.m. PST |
some were USA 76mm armed tanks, very few real firelfy's in the film |
Gunfreak | 22 Mar 2018 1:07 p.m. PST |
What is the major difference between the 76 and 17pdr superficially? When I Google one or the other. I can't see any major differences. Both are long and big with muzzlbreak. |
John Leahy | 22 Mar 2018 1:13 p.m. PST |
The turret was different on the Firefly. |
Gunfreak | 22 Mar 2018 1:20 p.m. PST |
So turret more then the cannon it self. |
Dynaman8789 | 22 Mar 2018 1:29 p.m. PST |
For even more fun, when the Shermans start moving look at the ground between them – at least one of them is being towed by the one in front. You can see the chain snap taught between them. One of my favorite movies though. |
Neroon | 22 Mar 2018 1:51 p.m. PST |
@ Gunfreak Go here link Educate yourself. cheers |
Jeffers | 22 Mar 2018 3:28 p.m. PST |
Some were fibreglass shells made to fit into landrovers for the Bailey bridge crossing scene. Had my photo taken next to one at the sadly defunct Lamanva Military Vehicle Museum in Cornwall (this would be about 1980 – the museum also had the mock up of a Horsa glider cockpit and the Pz4 used in an episode of the Goodies!). Apparently Leo1s were used to bulk up the armoured column in the long shot of Michael Caine moving up the highway, but I've never managed to spot one. |
Dynaman8789 | 22 Mar 2018 3:50 p.m. PST |
I would have liked to see one of the mockups! |
Dynaman8789 | 22 Mar 2018 3:51 p.m. PST |
That makes me wonder why they didn't use a mockup for the Panther (?) tank in the one scene – it didn't even need to move after all. edit – just remembered, they used the same tank for the Arnhem Bridge scenes. Makes sense to use it over. |
Osterreicher | 22 Mar 2018 5:10 p.m. PST |
The basic ballistics of the Sherman 75mm vs the 17pdr depend naturally on the shell they are firing, but here are some typical ammunition used with the ballistics. 75mm L/40 500 yards – 70 1000 yards – 59 1500 yards – 55 2000 yards – 50 17 pdr L/55 (APCBC / APDS) 500 yards – 125- 187 1000 yards – 118 – 170 1500 yards – 110 – 153 2000 yards – 98 – 135 76mm (APC) 500 meters – 98 1000 meters – 90 1500 meters – 81 2000 meters – 76 Basically, the 17pdr could kill a Tiger (and everyone else except the Tiger II) from the front under 500 yrds and possibly at 1000 yards. The 75mm couldn't really kill the Tiger except in the rear or hitting the tracks. The 76mm was only slightly better. From the side, the 17pdr could kill the Tiger at most ranges, just ask Herr Wittmann. Both the 17pdr and 75mm gun had similar diameters 76.2mm vs 75mm but the shell for the 17 pdr was massive. |
jowady | 22 Mar 2018 5:50 p.m. PST |
Indeed, the shells for the 17 pounder were so large that the Fireflies lost the "co-driver" machine gun position and used the space for ammo. The 76 didn't really become a tank killer until they got HVAP ammo. |
mysteron | 23 Mar 2018 2:00 a.m. PST |
If someone is looking for a European WW2 force to use the 76mm and Firefly together then take a look at the Polish 1st Armoured Division. A very interesting unit IMO. I started on such a force in 20mm . Still needs a lot of work to finish off and plenty of spare tracks to cover the tanks with. The Firefly is far superior to the 76mm Sherman in terms of hitting power. |
Fred Cartwright | 23 Mar 2018 2:06 a.m. PST |
The 76 didn't really become a tank killer until they got HVAP ammo. Even the HVAP was not that good. It only brought the penetration of the 76mm gun up to that of the standard APCBC of the 17pdr. |
mysteron | 23 Mar 2018 3:36 a.m. PST |
I am just wondering why the US never adopted the 17 pounder Fire fly ? I presume logistics of resupply must have been a factor as they did trial one. So they new from the testing how superior it was. With the US industrial might , troops of just fireflies could have been a possibility.I am not sure such a prospect would have shortened the war but it certainly would have helped. |
Patrick R | 23 Mar 2018 4:18 a.m. PST |
US 3-inch gun APBC penetration at 500m : 121 mm 17-pounder APBC at 500m : 137mm US 90 mm APBC at 500m : 150mm US 3-inch HVAP @ 500m : 208mm 17 Pounder @ 500m : 256mm US 90 mm HVAP @ 500m : 278mm First of all the 3-inch gun was considered too big to fit inside the M4 medium's turret and leave enough room to allow the crew to fight effectively. The 17-pounder was even bigger and could only fit when turned sideways. This was a tradeoff the British were prepared to accept, mostly because they didn't have an alternative. The US did have an alternative : the 90mm which was already in production, was even better than the 17-pounder and more accurate at range and Ordnance had managed to make it lighter and more more compact so it could be dropped into an M10 with minor modifications and the turret was transplanted on M4 tanks to create the M36B1 and B2. There was a program to adapt the T-25 turret to the M4 as an stopgap vehicle until M26 became available, but since the new 76mm gun was available and combining the E6 and the E8 upgrade programs into the M4A3(76)W HVSS aka the "Easy Eight Sherman" resulting in a tank that was quite capable of taking on Panthers. The problem is that because the 17 pounder was such a powerful gun, everyone assumes it was the best possible gun available, which it wasn't … certain the Ordnance Board after extensive testing didn't think so. The only time they did consider adopting the 17-pounder was after the so-called "Panther Panic" during the Battle of the Bulge when several hundred fireflies were ordered to supplement US stocks, but given that Panthers performed very poorly in the Ardennes, larger numbers of M36 became available and the M26 was arriving in Europe, it became a moot point. |
troopwo | 23 Mar 2018 7:21 a.m. PST |
Additionally the 17pdr could fire the APDS round which had even more incredible ability to punch through whatever it came up against. Keep in mind it was still a Sherman, meaning that just aout anyone and everything could knock it out as well. Should there have been 75mm Shermans? Absoluitely. The norm was three 75mm Shermans for each Firefly. However, after the war, the 75mm Shermans were either upgunned or scrapped as better tanks became available. The 76mm and 17pdr versions were retained by armies in service for longer periods of time as they could still compete into the fiftiie and so on. I understand that when they made the movie, they scrounged museums and private collections for running vehicles. Rumour has it even a few Fireflys made it back from Argentina for the film! Hope that helps. |
shaun from s and s models | 23 Mar 2018 7:29 a.m. PST |
the us army has 12 fireflys in italy aparently, not sure if used in action or not. |
Garand | 23 Mar 2018 7:37 a.m. PST |
The biggest issue with the 17pdr as Patrick R says above was accuracy. The rifling twist of the barrel was not suited for firing APDS rounds, & IIRC the muzzle brake didn't help either. So that accuracy when firing the APDS was abysmal (under 50% at ranges where the 75mm & 76mm were between 90-100%). Plus with the 90mm already well advanced when testing was done, led the US Army to pass over the weapon in favor of the 76mm & 90mm. This wasn't an issue of "Not Made Here" either, since the US was churning out 6pders for their own use as well as for lend-lease, as well as other productions (universal carriers, FREX) to supply the British war effort. Damon. |
Marc33594 | 23 Mar 2018 7:55 a.m. PST |
Just to follow on to Patrick's comments on fitting the 17pdr in the turret another modification had to be made to accommodate the radio. Normally mounted at the back of the turret interior on British Sherman's, an armored box was built on the rear of the Firefly turret to house the radio and a hole cut in the turret to access it. Added on to that was a "blanket box" for storage. One reason the Firefly turret is rather distinct with two boxes, one behind the other, on the rear of the turret. A new hatch was also cut in the top to allow the loader the ability to quickly exit the tank. |
mysteron | 23 Mar 2018 8:09 a.m. PST |
All this Sherman Luv, its getting too much :) |
Fred Cartwright | 23 Mar 2018 8:44 a.m. PST |
First of all the 3-inch gun was considered too big to fit inside the M4 medium's turret and leave enough room to allow the crew to fight effectively. The 76mm gun did fit in the standard turret, but the US considered it too cramped. However post war they did replace the 75mm with a 76mm gun in the standard turret. The Sherman's used in Kelly's Heroes are modified tanks. The British knew the Firefly turret was cramped, but that didn't seem to stop them using it effectively. Not sure why the Brits weren't offered the T-23 turret for the Firefly conversion. The 76mm US and British Firefly went into production at the same time. The problem is that because the 17 pounder was such a powerful gun, everyone assumes it was the best possible gun available, which it wasn't … certain the Ordnance Board after extensive testing didn't think so. The only time they did consider adopting the 17-pounder was after the so-called "Panther Panic" during the Battle of the Bulge when several hundred fireflies were ordered to supplement US stocks, but given that Panthers performed very poorly in the Ardennes, larger numbers of M36 became available and the M26 was arriving in Europe, it became a moot point. Both the M36 and HVAP were late developments and in short supply though. By the time they arrived there was hardly and German armour facing the western allies. The Firefly might not have been the best solution, but it was the only one around when really needed. |
Thomas Thomas | 23 Mar 2018 9:40 a.m. PST |
Putting the 17pder in M10s was an easy conversion and could have been adapted much earlier to create an excellent hybrid tank destroyer (which of course the UK did). Had the US/UK combined as they did for the Mustang and placed in full production, plenty would have been available by June '44. The US landed in Normandy without an adequate means of dealing with either Panthers or Tigers but, very fortunately, it was the UK that took on the overwhelming bulk of the German armor and they did have a means of dealing with it. That the US finally got some 9.0L TDs in action (long after Normandy) and a trickle of HVAP hardly justifies not embracing the 17pder prior to invading Europe. Its also a mystery why the US when developing a new turret for the M4 did not consider making it adaptable for the 17pder without all the work required to modify the existing turret – so we got a brand new turret that only worked for the inferior 7.6L. I'm more familar eith the date presented by Osterreicher regarding the US 7.6L – generally about equal with the German 7.5L but inferior to both the 17pder & 7.5XL. I've never seem prior data that the US 9.0L was superior to the 17pder – but we live and learn. As to accuracy of the 17pder the problem was adapting to discarding sabot not in general. The 17pder normal round was deadly enough and accurate. TomT |
Dynaman8789 | 23 Mar 2018 9:59 a.m. PST |
Was the US making 17lber guns before 44? Would a factory need to be retooled to do so? For good or ill the kit that was going to Normandy was decided upon in mid 43 at the latest, built, and then shipped over. For good or ill, good being there were a LOT of Shermans out there with Ill being they were armed with an inferior gun for Anti-Tank work but an excellent HE thrower, the decisions were made to maximize production. |
Mark 1 | 23 Mar 2018 10:40 a.m. PST |
What is the major difference between the 76 and 17pdr superficially? Interpreting this as a request for the visual identifiers, I would suggest that there are several visual differences, and one might identify a Firefly by any of these depending n what part of the tank is visible. I use the first 2 as my primary guides -- the 3rd and 4th only really when seeing a small part of the tank from an odd angle. 1 ) Muzzle brake: All Fireflies had a muzzle brake. During the war very few Sherman 76's had muzzle brakes mounted. The barrels were usually threaded for them, but most tanks in service had a thread cap in place rather than a brake. Some small portion sported muzzle brakes, and they became common after the war. But they always looked very different from 17pdr brakes. The 17pdr brake, as observable on Fireflies, was rather rounded … looks almost like a ball with holes drilled in it. The muzzle brake for the 76mm M1A1 was far more angular, with a kind of flat front appearance.
2 ) No hull MG. As others have mentioned, the co-driver (hull gunner) position was used for ammunition storage in Fireflies. So the hull MG ball mount was removed, and the opening in the hull was plated over. If you can see the front slope of the tank, this is an obvious modification that clearly marks a Firefly. 3 ) Elongated turret rear. As others have mentioned, the size of the 17pdr meant that the radio no longer fit in the normal Sherman turret bustle. So as part of the conversion process the back of the turret was cut out, and an extended armored box was added to hold the radio. If you can see the side or rear of the turret, this is an obvious modification that clearly marks a Firefly. 4 ) Hull. Most Fireflies were converted from M4A4 tanks (Sherman V in Brit-speak). This was a welded hull (not a rounded cast hull) version of the Sherman. It was also an elongated hull, due to the extra engine compartment space needed for the Chrysler multi-bank engine. The easiest way I find to identify the stretched hull it to look at the roadwheels. In any other version of the Sherman than the M4A4, the wheels on a given bogey are clearly farther apart than the wheels between two bogies. On the stretched hull the bogeys are spread out more, and this is no longer the case. Honestly I find this to be a rather subtle observation point. M4 tanks (Sherman I in Brit-speak) were also used for Firefly conversions (though not as many as the M4A4s). These are also welded hulls, so no rounded castings. But they did not have the extended hull length. A few M4 "hybrid" hulls were converted. These are really kind of hard to see. They have the rounding on the hull front from a cast front piece, but the sharp angled edge along the hull sides and rear of a welded hull. Some small number of Grizzlies (Canadian-built M4A1s, Sherman II in Brit-speak) were converted to Fireflies in Canada. But I don't believe any of these were shipped to ETO. All of these tanks had VVS (Vertical Volute Suspension). The result of all this mumbo-jumbo is that if you can see enough of the hull to judge it to be an M4A1, an M4A2, or an M4A3 … it isn't a Firefly. And even if you can't see enough of it to judge that it is an M4A1 or M4A3, if you see enough of the suspension to judge that the tank has HVSS (Horizontal Volute Suspension System -- as on the US Army "Easy 8" Shermans) it isn't a Firefly. Hope that helps. -Mark (aka: Mk 1) |
Mark 1 | 23 Mar 2018 10:57 a.m. PST |
I am just wondering why the US never adopted the 17 pounder Fire fly ? I presume logistics of resupply must have been a factor as they did trial one. The US forces in ETO requested Fireflies from the British, and the British agreed to supply them. But the logistics issues kept it from becoming a reality. Not so much on resupply, but just initial supply. The Brits developed conversion kits for M4 and M4A4 Shermans. As the conversion involved a lot of interior re-construction, the kits only worked on the Sherman versions they were designed for. The conversion work was generally considered to be factory work, not in-theater depot work. They agreed to do provide the kits and use their factories for conversions, but on tanks supplied by the US Army ETO stocks. They did not agree to give British stocks of tanks to the US ETO forces. And they agreed to do the conversions only after they had converted enough for their own requirements. Both sides agreed to that approach. The US Army in ETO didn't have any stocks of M4A4s. It never operated that type. So it was going to be M4s. In the run-up to Overlord the British were still building out their own stocks of Fireflies. After the Normandy break-out, they offered to start the conversions of M4s for the US Army. The US Army had underestimated it's own likely loss rates of armor in action, and ETO was short of tanks after the Normandy break-out. No M4s could be spared for conversion until supply to the ETO was expanded. Then British army changed it's ratio of Fireflies to 75mm armed Shermans, upping their own required volume of Fireflies by some 25-30%. By the time the US ETO had enough extra M4s to provide some for conversion, the Brits were busy converting Fireflies for their own requirements again. In the late winter / spring of 1945 there were finally enough extra M4s in US inventories AND conversion capacity in British factories, and IIRC something like 100 tanks were converted for the US Army. But the US Army in ETO was already receiving M26s and HVAP for their 76mm-armed Shermans, and so had lost interest in Fireflies and never bothered to accept and deploy any of the Fireflies that were in fact converted for them. At least that's the timeline I understand. Was the US making 17lber guns before 44? Would a factory need to be retooled to do so? The US never produced 17pdr guns or ammunition. The modifications to produce a tank gun based on the existing US 90mm AA gun was considerably less than the time it would have taken to tool up for an entirely new gun. And … US Ordnance took a long time to get their heads around accepting/building a gun that only had a barrel life of 100-120 rounds. US standards were for barrel life of more than 1000 rounds. -Mark (aka: Mk 1) |
troopwo | 23 Mar 2018 11:05 a.m. PST |
There were a few problems with the 17pdr. The flash was tremendous making corrections difficult. Often they would have accompanying tanks give directions when it was too hard to observe difficult shots. That is why the muzzle brake was fitted. The APDS rounds were geenerally not as accurate until developments in the fifties for the 20 pdr. However, it did punch through a lot and was acceptable for use, rather like the US HVAp rounds. The US 76mm was fitted into the little 75mm turrets. Especially in the postwar rebuild schemes that went on in Japan after the war. Operation Roundup(?). This really happened at the start of the Korean War when there was a panic about being able to take on T34/85s. As said, the vehicles in Kellys Heroes were these upgunned models. They worked but were cramped. In '44 the US army did not want the hassle of major re-work programs when they knew the new turret and gun combinations were in the pipe line. The US 76mm was marginally better, but not anyhwere as good as it was hoped it would be. I have seen pictures of Patton somewhere after the panic on discovering the dissapointment that the 76mm was not all it was claimed to be. From the look on his face he seemed bitter enough to crack coconut husks using his butt cheecks. So the US went whole hog into continuing with the 90mm. The Firefly turrets simply mounted the gun in the same trunnioons that the 75mm was in. The length of the gun internally made it necessary to cut out the back of the turret and add the radios into that box extension extending beyond the back. The extra Loaders hatch and use of the codirvers spot for ammo storage has already been brought up. It makes it a bit interesting to compare the Firefly modifications to what the French, Isrealis and Indians did to mont the French 75mm into the small turret in the mid fifties. They welded added cheek pieces to extend the trunnions further forward and then added a similar turret extension to the rear of the turret much like the box on the back of the Firefly. It gave more room in the turret as well as giving some slight counterbalance results. The Indian Army tried to use the same French 75mm gun in an small turret. They simply mountedd the gun into the existing trunnions with little modification to the mantlet . The result was that the weight of the gun barrels stripped out al the turret gearing when driving cross country. Not a lot of people have done much looking into the Indain Army mods. The T23 turret, designed for the 76mm, was actually fitted so that it would easily take or accept the 76mm or the 17pdr with little to no modification. I think it was also the case for a 105mm howitzer too. When in doubt dig into Hunnicutts bible on the Sherman. |
Jeffers | 23 Mar 2018 11:16 a.m. PST |
Dynaman: link Hopefully this works. Ignore the sartorial failure in the centre. I was training to be a lumberjack. |
troopwo | 23 Mar 2018 11:17 a.m. PST |
Almost forgot. The 76mm Shermans were also highly used by the British Army too. Both in Italy, and in NW Europe too. The 1st Polish Armoured Div was euqipped totally with 76mm version by wars end. This only happend after production really ramped up and there were enough to go around,,,say Jan '45. The British ramped up conversions of Fireflys too. By the end of the war, most units had a Firefly for every 75mm version, a one to one ratio. |
Fred Cartwright | 23 Mar 2018 6:26 p.m. PST |
It is also worth noting that the Us Ordnance officers that tested the 17pdr vs the US 76mm were not dismissive of the 17pdr at all, but merely of the APDS ammo. They considered the 17pdr would be a good gun with HVAP rounds to give penetration and accuracy. They are also critical of the US decision to shorten the 76mm to fit the Hellcat turret, rather than altering the turret to fit the gun. They felt it compromised its penetrating power too much. The ultimate cat killer Sherman was never produced, which would have been the 17pdr in the T23 turret firing HVAP ammo! The British didn't get T23 turrets until they had largely completed their Firefly conversions and the US never accepted the British offer of 17pdr barrels to fit in their tanks. |
Lee494 | 23 Mar 2018 8:25 p.m. PST |
Actually it seemed to me like many of the Shermans and M3 Halftracks were Israeli Army variants. Was any of their equipment used for the film? Cheers! |
Martin Rapier | 24 Mar 2018 2:10 a.m. PST |
I think they just cobbled together what they could. A Chaffee appears in one scene, and that dunkelgelb Leopard gets a couple of outings. Whatever. It is a cracking film. The thing which always makes me chuckle is the portrayal of Graebner, who was anything but the jut jawed Aryan hero in real life, but was instead rather short, rotund and dark. |
BattlerBritain | 24 Mar 2018 4:15 a.m. PST |
I remember seeing a Leopard 1 with additions to the turret to make the sides flat, like a Panther, in the German attack across the bridge. Some good stuff in the film. |
Garde de Paris | 24 Mar 2018 2:09 p.m. PST |
Mark 1 posted this information on 21 Jan 2018 12:57 p.m. PST Cruising some US WW2 footage on YouTube just today I found this: YouTube link (not working here) Dated early August 1944 look in the first minute of footage, at the US 57mm gun crew and the ammunition they are passing forward. Rounds two and four are clearly sabot rounds as you can see the step where the sabot petals meet the AP core. Quite agree. Rounds 2 and 4 are clearly Sabot rounds. Some sources and some war gamers/historians claim that the US 57mm did not use the APDS (armour-piercing discarding sabot) in late WW2 despite its use by the British from June 6 onwards in the six-pounder/57mm and the issue (about a month later) of a 17-pounder APDS round. … Previously I had found on-line accounts that US 57mm used the sabot round during the Battle of the Bulge but it is unclear how the rounds were obtained as the US never manufactured sabot during the war, preferring the less effective US APCR. The US Army did not provide Sabot rounds for the 57mm gun. That does not mean British rounds would not work. It only means that a US crew who had Sabot rounds got them from the British supply lines, not the US supply lines. British APDS 57mm rounds were test-fired in US 57mm guns on several occasions. The desperately poor accuracy caused the US Army to look other ways for increasing penetration. Many excuses were offered in the test firings for the exceedingly poor accuracy of British APDS rounds, but in truth most British WO test firings showed equivalent accuracy to the US test firings. The British army was simply more willing to accept ammunition that could hardly hit the broad side of a barn if that ammunition had better odds of penetrating that barn once hit. The effect of sabot is to greatly increase the armour-piercing capability of the gun. APDS has no necessary advantage over APCR at short to medium ranges. Both are very light rounds for the caliber of the gun, and so start with very high initial velocity. Both have very hard metal cores (typically Tungsten), and so can use their velocity well to penetrate armor. APDS has an technical edge over APCR once you get to longer ranges, as it discards the light weight full-caliber wrapper around the core, and with the resulting change in diameter-to-mass ratio has lower wind resistance and so retains it's initial high velocity better over distance. That was irrelevant in WW2, as British APDS was unable to hit a target at longer ranges. So who cares that it's going faster as it flies off to the horizon? Some examples of WW2 era APDS accuracy: First, from the British perspective … WO 291/751 AORG Memo No.427, 24th Nov 1944, "Comparative Dispersion of Tank Guns" Probability of a hit when firing for effect on a target 2' high by 5' wide (M.P.I. assumed on centre of target) @ (yards) ……….…………………… 500yds; 800; 1000; 1500: Churchill IV 6pdr APCBC 150rnds……74% .. 73% .. 62% .. 42% Churchill IV 6pdr APDS 90rnds…….…74% .. 50% .. 37% .. 20% Sherman 17pdr APC 100rnds………….88% .. 66% .. 52% .. 32% Sherman 17pdr APDS 40rnds………….42% .. 21% .. 14% .. 7% Comet 77mm APC 40rnds………………98% .. 86% .. 76% .. 53% Sherman 75mm M3 APC M61 150rnds…100% .. 96% .. 90% .. 73% Sherman 76mm APC M62 40rnds………100% ..100% .. 96% .. 92% Please note that the British fired 90 rounds of 6pdr APDS, and scored only 50% hits on a tank turret sized target at 800 yards range. And that is ON A RANGE, with no ranging errors and no combat stresses. When the British fired US 76mm APC ammo at that same distance, they scored 100% hits. The British 17pdr APDS scored even worse, hitting less than 50% of the time at 500 yards! At 800 yards it scores 21 percent chance of a hit! Again, that's on a range, without stress, when the distance is perfectly known. In a post-war US Army Ordnance test of the Sherman Firefly firing APDS conducted postwar in 1946, comparative results were sought firing at a 6" thick test plate that was 5.5ft wide by 4.5ft tall, setback at 30 degrees. At a range of 1,050 yards the testers were able to achieve only two hits, one of which had such shallow and wide strike that it was concluded to have been a side-slap of a ricochet from striking the ground in front of the target. After firing 38 rounds at the target, the Ordnance team went off to do something more productive with their time. This was effectively a repeat of the US wartime testing, where you can see in excuses of the "official language" the frustration of the testers, who were ordered to publish comparative results but could not manage to enough hits on the targets to draw useful conclusions, even when they had experienced British gun crews do the firing for them. A hoary old story was that the US guns 'could not fire APDS as the twist of their rifling did not match the British guns'. I don't know much about that hoary old story, but it is true that the rifling in US guns was not optimized for sub-caliber rounds. But then, neither was the rifling in British guns. Which was one of the contributing factors to the abysmal accuracy of British APDS during WW2. The US continued to reject APDS throughout the late 1940s and 1950s. The US never provided an APDS round for the 90mm guns that armed US MBTs in the M46, M47 or M48 series. US HVAP rounds (the US Army Ordnance designation for what the Brits called APCR) continued to provide every bit as much penetrating power as British APDS at short to medium ranges, with pin-point accuracy, while the US Army preferred HEAT rounds for long range engagements. The British did resolve the accuracy of their APDS rounds, and later British tank guns, including later marks of the 20pdr gun, were in fact rifled specifically for APDS as their standard AP round. When the US adopted the British L7 gun as the 105mm M68 for use in the M60 tank (and later upgraded versions of the M48), the issues of 1944 had been resolved, and the technical superiority of APDS ammunition were clear enough that US Army Ordnance changed it's conclusion and wholeheartedly adopted the round. But we should not let the post-1960 experience with APDS drive our understanding of the 1944 experience with APDS. There can be little doubt that British wartime APDS was very capable in armor penetration. But it was also a round that could miss the ocean from a boat. British priorities meant that it came into service, and those who used it spoke highly of it's penetration. Those who used US HVAP spoke highly of it's accuracy. That said, initial US HVAP did have some difficulty with ricochets from highly sloped plates. I believe (never seen conclusive analysis, so just a belief) that this was due to the "shoulder" that these rounds retained. If the shoulder struck the armor before the point of the core, it may have initiated side-forces to encourage a bounce. These were resolved in the various sub-types of HVAP rounds that became available in the very last months of the war. Also, the US was FAR behind on producing and supplying HVAP during WW2. Of that there can be little doubt. None of the initial production requirements were met. The rounds were far too slow to come into widespread availability. Doesn't mean that APDS was somehow a magic silver bullet. Nor even a better round in the WW2 timeframe. But certainly the British gun crew with APDS was happier than the US gun crew who had heard of HVAP but didn't have any. -Mark (aka: Mk 1) |