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Sharing this tidbit to demonstrate how changes get made and go unnoticed after time.

Original M19 cupola for the M60 was discovered to have some flaws with it's protection so they redesigned it. Very subtle and the change came about with the introduction of the M60A1 turret. Noticed this when looking at images of M60A1 and M60A3 tanks which had older M60 cupolas. They were easily ID'd by the mounting pad welded on the L/S above the second vision block for the .50 Cal. The Part #'s cast were different from the later cupolas. Welding a pad wouldn't change that so I delved into it further.

Discovered the new splash guards were the change.

M19 cupola on M60

M19 cupola on M60A3

M19 cupola L/S on M60

M19 cupola on M60A1

You can see the obvious changes designed to prevent bullet splash entering the cupola. Being primarily an Anti-Aircraft weapon the guards covered areas exposed when level and elevated. Someone somewhere discovered this weakness and incorporated the design change, but I haven't found any reference officially doing this anywhere. Most likely in some dusty archive somewhere lost. Not something that can be done on a whim and had to have official blessing. The Part #'s that actually changed were the cupola, #10873386, and the cover assembly, #0873140. Later castings were #10911781 and #0915610 respectively. When you look them up in the parts manual they are listed differently for the M60 from the later A1/A3 and M728 CEV, so they were not officially interchangeable. M60 cupolas installed on later tanks had to be modified.

M19 cupola modified for use on M60A1

They welded on the new splash guards to maintain the same standard throughout the fleet. Had to be a Depot operation. Don't just see these on rebuilt/converted A1's to A3's either, seen them on New Detroit A1's and A3's too. Guess when we sent all those M60's to Israel they reused the cupolas for tank production here. Israel did not use them on their tanks and technically being paid for with US foreign aid they were US property to be returned when no longer needed. Saved the Taxpayers a lot of money reusing them, having to reduce the order for castings on new tanks. Just a theory but does make sense and explains how those older cupolas got on later tanks. Also, not visible externally but the hatch part # changed too, since the later versions had a different type locking mechanism which required a larger mounting boss for the handle.

Now that's trivia guys

Hi, Joe!

Looking at that last pic carefully, I got myself to wondering why the cupola wasn't built with an armored, hinged flap that lifted forward from the hatch position above the gun and feed tray to facilitate servicing of the weapon. The TC would still be mostly behind armor when open and wouldn't have been much heavier than a loader's hatch and would have prevented untold amounts of cussin'.

M48 and M60 family hand-cranked cupolas were some the most poorly conceived items ever inflicted on a tank. Cost a bundle and near universally hated.

D.

The cradle access door opened in the manner you described, to allow access to the gun cover assembly, providing a measure of protection....were you suggesting something bigger?

And, yeah, that cupola was an absolute waste of money.

- Jstar

The cradle access door opened in the manner you described, to allow access to the gun cover assembly, providing a measure of protection....were you suggesting something bigger?

And, yeah, that cupola was an absolute waste of money.

Yes, absolutely, much bigger. I don't think they had gas strut technology then like what's on my car now, but that would have been nice, too. I have time on all iterations of M60 (except the A3, which was after my time) and two versions of M48. Access was not what it needed to be if it was ever to be used under the pressures of combat. It all aimed pretty precisely out on the range, but reloading or any other service was not going to be wieldy if there was lead in the air other than your own. And it was still a pain even in controlled conditions.

I'm of the opinion that if one is going to use a cupola option, it must be powered and easy to service, even at the cost of greater size and complexity. Otherwise, you're better off with a pintle mounted weapon and a gunshield.*


*and that goes for the APC's as well. Trying to spin a protected pintle mounted heavy MG with shields manually is asking a lot (BTDT), especially out there in the real world where the ground is rarely level and you might have to face threats from more than one direction, or maneuver your vehicle such that your have to rotate a heavy cupola with your feet hooked in what amounted to a sturdy towel rack (which was only useful for 180 degrees of travel or less).

Moderndevelopments on these matters seems to have caught up with what should have been fairly evident by the mid-'60's.

- Joe_D

The Part #'s that actually changed were the cupola, #10873386, and the cover assembly, #0873140. Later castings were #10911781 and #0915610 respectively.

Joe, the covers were actually 10873140 and 10915610, to be consistent with the drawing number sequences used on everything else. You can see the full number in the picture of the cover with the cast-in lip.

KL

Cool beans. Interesting detail info, that I probably never would have noticed! Those parts are pretty much always completely covered, so unless you are prowling around relics with their canvas covers shredded you'll never notice there is a difference.

IIRC, the M60-series came about during some really secret-squirrel times of the Cold War, so I expect that any discussion of the design changes was immediately classified. It's probably declassified now, but Lord only knows what vault or file archive the documents are buried in.

Having never developed the double-jointed wrist and third elbow to be able to effectively reload the M85 without exiting the cupola, and the coordination to traverse and elevate the thing anywhere but on stationary, flat range firing points, I agree that the M19 cupola sucked. The MG itself sucked too.

C

Kurt,

Right you are, I don't know how I left off the 1 on both. I culled out the pictures to post but I have some good shots of both style covers with the part numbers in plain sight. Some of those covers it's located under the canvas but others it's cast in near the bottom upside down, just depends who the foundry was.

Dealt with the M19 cupola and M85 for 7 years off and on and yeah, it was not the easiest to work with but generally I had no problems with either for the most part. Always kept a large screwdriver handy to feed the rounds up through the chute and being tall made it easier to reach over the sight housing to open the covers and load. One of the later and better ideas that came out with the A3 was the last round over ride function. Kept you from completely expending all your ammo so you could link up another belt without having to reload the weapon. The biggest issue I had with that cupola was the poor visibility, since all the vision blocks were really tiny and you didn't have any forward. When I first got on the M1 I loved the new periscopes and especially the forward one. Hated the weapon station though. Really poor design and under utilized the M2 capabilities. Broke easy too with that brass gear and pinion design. And don't get me started on the stupid combination elevation wheel and trigger. At least on the M1A1 they finally put an electric solenoid on it. Guess they gave up with the M1A2 and went with a pseudo flex mount.

Doug, Amen on the heavy protected pintle mount being a pain. In Iraq we had M1114 Humvees with the armored cupola and gun shield, Manual traverse handle that was not up to the task after we started putting additional armored front windshields on the sides for protection. Got even worse when they made those "Pope Mobiles" and put them all around the gunner. Hated those and when we got a loaner the first thing I did was remove them and install them on the sides. Right before I left the team I was with got the "Rock Island" turrets installed along with other armor upgrades. Electric traverse with a joystick control box that was magnetically attached, so the gunner could place it where it was most comfortable. Even came with nice big rear view mirrors. Used the same motor drive as those fancy electric wheel chairs.

The best I worked with, and mind you this was with the OPFOR in Irwin, was the M551 cupola. Standard flex mount but the cupola was electric traversed. Had a cable that ran out side to connect remote control. Never could get the original ones but some were rigged up a DPDT toggle switch to make it work. Some really "Smart Guy" got an old CVC cord and rigged up some thumb triggers that attached to the back plate hand grips. Squeeze left, traverse left, squeeze right, traverse right.

- Joe_D

Kurt,

Right you are, I don't know how I left off the 1 on both. I culled out the pictures to post but I have some good shots of both style covers with the part numbers in plain sight. Some of those covers it's located under the canvas but others it's cast in near the bottom upside down, just depends who the foundry was.

Dealt with the M19 cupola and M85 for 7 years off and on and yeah, it was not the easiest to work with but generally I had no problems with either for the most part. Always kept a large screwdriver handy to feed the rounds up through the chute and being tall made it easier to reach over the sight housing to open the covers and load. One of the later and better ideas that came out with the A3 was the last round over ride function. Kept you from completely expending all your ammo so you could link up another belt without having to reload the weapon. The biggest issue I had with that cupola was the poor visibility, since all the vision blocks were really tiny and you didn't have any forward. When I first got on the M1 I loved the new periscopes and especially the forward one. Hated the weapon station though. Really poor design and under utilized the M2 capabilities. Broke easy too with that brass gear and pinion design. And don't get me started on the stupid combination elevation wheel and trigger. At least on the M1A1 they finally put an electric solenoid on it. Guess they gave up with the M1A2 and went with a pseudo flex mount.

Doug, Amen on the heavy protected pintle mount being a pain. In Iraq we had M1114 Humvees with the armored cupola and gun shield, Manual traverse handle that was not up to the task after we started putting additional armored front windshields on the sides for protection. Got even worse when they made those "Pope Mobiles" and put them all around the gunner. Hated those and when we got a loaner the first thing I did was remove them and install them on the sides. Right before I left the team I was with got the "Rock Island" turrets installed along with other armor upgrades. Electric traverse with a joystick control box that was magnetically attached, so the gunner could place it where it was most comfortable. Even came with nice big rear view mirrors. Used the same motor drive as those fancy electric wheel chairs.

The best I worked with, and mind you this was with the OPFOR in Irwin, was the M551 cupola. Standard flex mount but the cupola was electric traversed. Had a cable that ran out side to connect remote control. Never could get the original ones but some were rigged up a DPDT toggle switch to make it work. Some really "Smart Guy" got an old CVC cord and rigged up some thumb triggers that attached to the back plate hand grips. Squeeze left, traverse left, squeeze right, traverse right.

Most of our Sheridans in VN had the TC's turret override control handle relocated outside of the turret and into the "teacup" where he could just aim and fire everything from that position. The hydraulics were long enough so you just needed to fabricate a bracket to which to mount the turret control handle As there was no "gunner" in the formal sense, Sheridan gunnery was effectively a two-man operation with a driver and an aux MG gunner at the loader's hatch that would drop down and load any main gun rounds called for.

- C_Sherman

Cool beans. Interesting detail info, that I probably never would have noticed! Those parts are pretty much always completely covered, so unless you are prowling around relics with their canvas covers shredded you'll never notice there is a difference.

IIRC, the M60-series came about during some really secret-squirrel times of the Cold War, so I expect that any discussion of the design changes was immediately classified. It's probably declassified now, but Lord only knows what vault or file archive the documents are buried in.

Having never developed the double-jointed wrist and third elbow to be able to effectively reload the M85 without exiting the cupola, and the coordination to traverse and elevate the thing anywhere but on stationary, flat range firing points, I agree that the M19 cupola sucked. The MG itself sucked too.

C

As time permits, I'll peruse some documents that arrived at my house anonymously on an external HD and see if there's anything to be gleaned from those. During that era, there was a lot of sensitivity to cost on these systems (tanks as early as '58 were considered for 120mm guns, ergo the spacious turret of the M48 and it's successors. Decision was made to milk the ballistic performance of the 105 to it's logical limit before shopping for all new guns.

Doug

Sounds like you are overdue for some 'professional reading'...




Don

- C_Sherman

IIRC, the M60-series came about during some really secret-squirrel times of the Cold War, so I expect that any discussion of the design changes was immediately classified. It's probably declassified now, but Lord only knows what vault or file archive the documents are buried in.

C

It's probably more likely that it just wasn't that important. Going by my research into Shermans and Stuarts in WW II (where all the info, secret on down, is available) there were hundreds of changes that were simply phased into production as improvements without any high level fanfare. Certainly there was some discussion at the engineering level, but much of this has been lost as it was really little more than day-to-day operations.

Today I work in a similar environment that has been making propulsion plants for the Navy for over fifty years. We have one of the most comprehensive systems I've ever seen for documenting actions and retrieving information, but on a weekly basis something comes up where people ask "Why is that there?" Sometimes we can find the answer, sometimes one of the silverbacks will remember a key detail, and sometimes we never find out.

KL

Kurt,

Agreed, your description of what happens at work says it best. I can imagine Anniston and what it was like when they were in full swing. Some things are best just solved at local level not requiring the stop in work for TACOM to approve. There are many "Sherman" aficionados who delve into this with the zeal of of a forensic scientist and archeologist. Looking at something and then trying to deduce why. I am that way with the M60 series, but have much less company. Maybe someday She'll get the respect she deserves for carrying the bulk of the Cold War on her shoulders for the US Armor forces, even though that was never the intent.

- Dontos

Doug

Sounds like you are overdue for some 'professional reading'...




Don

I've only scratched the surface of what's been made available. I especially enjoyed the "Kamp Report", among others.

- Joe_D

One of the later and better ideas that came out with the A3 was the last round over ride function. Kept you from completely expending all your ammo so you could link up another belt without having to reload the weapon.

We had the last round override switch on our late M60A1 (RISE) Passive tanks in 3AD ca. 1980. I don't know when this was cut into production - my tank was S/N 9816. I kinda thought it was a pain, but I only fired at Graf where we never reloaded the M85 feed tray (we had an allowance of 100-150 rounds, and if we fired all of that, that was all she wrote ... time to fire the main gun at a truck target (and there goes your Distinguished patch out the window :). But I can see its purpose in combat.