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Walter_Sobchak · ***Power User*** Offline Joined: Feb 20, 2013 Posts: 122

I was sorting through some old documents that a friend had given me and found a rather large stack of papers entitled "M60A1E2 Tank Characteristics and Description Book" from October 1971 put out by "U.S. Army Materiel Command Project Manager-M60 Tanks." Like most technical manuals, it is not exactly the most exciting read. But at the very back of the report, they have a section detailing various other guns that may be fit into the M60A1E2 (later called M60A2) with technical data and lists of what would be involved in the conversion. I found this surprising, I had always assumed that the ill-fated M-60A2 had been specifically designed for the 152mm missle launcher/cannon hybrid. I had no idea that other guns were ever considered for that turret. The guns listed in the document are the XM150, which was the longer barreled version of the 152mm gun/launcher hybrid intended for the MBT-70, the M68 105mm gun that equipped the other versions of the M-60, the 120mm T123E6, a smooth bore cannon developed by the US but never put into production, and the British 120mm L11A2 cannon that was featured on Chieftain. I thought this was worth sharing, I have uploaded the relevant pages of the document here. Hopefully someone may find this information useful or at least interesting.

Costas_TT · ***Power User*** Offline Joined: Feb 15, 2012 Posts: 387

That's funny... I have the old ESCI 1/72 kit and was always wondering what other guns I could use to replace the gun/launcher as part of a potential what-if build. I definitely considered the M68 and the M256, among others.
Thanks for posting this.

Walter_Sobchak · ***Power User*** Offline Joined: Feb 20, 2013 Posts: 122

Costas_TT wrote:

That's funny... I have the old ESCI 1/72 kit and was always wondering what other guns I could use to replace the gun/launcher as part of a potential what-if build. I definitely considered the M68 and the M256, among others.
Thanks for posting this.

I have a collection of 1/72 models, mostly prebuilt ones but some that I put together myself. I did not know there was a 1/72 scale kit of the M-60A2 out there. Looks like I'll have to check ebay for such a thing!

Doug_Kibbey

There would have been real limitations on alternative guns in the M60A2 turret as designed. Most high velocity guns have substantially more travel in recoil than the M81 did (I don't have the figures in front of me, but something like 7-8" comes to mind). M68/L7 guns recoil further and require clearance for a lengthy fixed brass cartridge upon ejection that simply wasn't there on the M60A2 (the TC turret mechanism being directly aligned with the gun).

Costas_TT · ***Power User*** Offline Joined: Feb 15, 2012 Posts: 387

Indeed. The guns would most definitely need some kind of system to limit recoil travel in order to clear the TC's position. Maybe the guns could be fitted more forward (i.e. having the trunnions closer to the breech) to leave room for the recoil and the recoil guard/casing deflector, in which case they might need some sort of counterweight at the breech end to maintain the balance.
On the other hand, the rounds fired by the M256 do not have as many limitations to impose on the use of the original A2 turret, as their casings are mostly combustible and therefore only a specially designed recoil system would be needed.

Doug_Kibbey

Re-hanging guns get tricky, balance is a critical factor. Also, anything that increases weight (like counterbalancing) further was a no-go on the A2, which already was ~5 tons heavier than an A1 and automotive performance was affected as a result. There was a requirement for 25mph on the straight and level, and this was probably not met on most of them as it was. Wear increased across all drivetrain components.

Unlike M48's and conventional M60 designs, the turret was not designed to accommodate updates (foreeen or unforeseen). It was what it was and would need to serve as the design had settled for it's (limited) life. Extending turrets in either direction was undesirable due to the already mentioned weight penalty and the already expansive vertical sides that nobody was keen to enlarge anyway for ballistic reasons.

Costas_TT · ***Power User*** Offline Joined: Feb 15, 2012 Posts: 387

Walter_Sobchak wrote:

I have a collection of 1/72 models, mostly prebuilt ones but some that I put together myself. I did not know there was a 1/72 scale kit of the M-60A2 out there. Looks like I'll have to check ebay for such a thing!

There is one, although, in common with other Patton tank variants made by Esci and currently marketed by Revell (M48s), the roadwheels are hideous and the tracks lack any sort of inner face detail. The Revell M60s are much better but they do not have an A2 in their product line yet.

Doug_Kibbey wrote:

Re-hanging guns get tricky, balance is a critical factor. Also, anything that increases weight (like counterbalancing) further was a no-go on the A2, which already was ~5 tons heavier than an A1 and automotive performance was affected as a result. There was a requirement for 25mph on the straight and level, and this was probably not met on most of them as it was. Wear increased across all drivetrain components.

Unlike M48's and conventional M60 designs, the turret was not designed to accommodate updates (foreeen or unforeseen). It was what it was and would need to serve as the design had settled for it's (limited) life. Extending turrets in either direction was undesirable due to the already mentioned weight penalty and the already expansive vertical sides that nobody was keen to enlarge anyway for ballistic reasons.

All these are valid points. I'll add that with the A2 turret config uparmoring its sides with modern add-on armor without fouling the loader and gunner's hatches would definitely be a bitch. But, now we are straying a bit too much into what-if territory.

Doug_Kibbey

Walter_Sobchak wrote:

I was sorting through some old documents that a friend had given me and found a rather large stack of papers entitled "M60A1E2 Tank Characteristics and Description Book" from October 1971 put out by "U.S. Army Materiel Command Project Manager-M60 Tanks." Like most technical manuals, it is not exactly the most exciting read. But at the very back of the report, they have a section detailing various other guns that may be fit into the M60A1E2 (later called M60A2) with technical data and lists of what would be involved in the conversion. I found this surprising, I had always assumed that the ill-fated M-60A2 had been specifically designed for the 152mm missle launcher/cannon hybrid. I had no idea that other guns were ever considered for that turret. The guns listed in the document are the XM150, which was the longer barreled version of the 152mm gun/launcher hybrid intended for the MBT-70, the M68 105mm gun that equipped the other versions of the M-60, the 120mm T123E6, a smooth bore cannon developed by the US but never put into production, and the British 120mm L11A2 cannon that was featured on Chieftain. I thought this was worth sharing, I have uploaded the relevant pages of the document here. Hopefully someone may find this information useful or at least interesting.

Thanks for uploading that, I already downloaded it successfully. My interest in this and any other documents you have links to or can transmit relates to having myself having reported to AMC (Test and Eval Cmd.-Armor Board) and was on the Initial Production Test Project for the M60A2. I also have an in-state contact who was at the Board before I was and was on the M60A1E2 project. Anything I can obtain would be much appreciated and would be shared with my colleague (who was also on the M551 project mid-late '60's). Thx in advance. You can PM me if we need to use other means for communication.

Walter_Sobchak · ***Power User*** Offline Joined: Feb 20, 2013 Posts: 122

Doug_Kibbey wrote:

Walter_Sobchak wrote:

I was sorting through some old documents that a friend had given me and found a rather large stack of papers entitled "M60A1E2 Tank Characteristics and Description Book" from October 1971 put out by "U.S. Army Materiel Command Project Manager-M60 Tanks." Like most technical manuals, it is not exactly the most exciting read. But at the very back of the report, they have a section detailing various other guns that may be fit into the M60A1E2 (later called M60A2) with technical data and lists of what would be involved in the conversion. I found this surprising, I had always assumed that the ill-fated M-60A2 had been specifically designed for the 152mm missle launcher/cannon hybrid. I had no idea that other guns were ever considered for that turret. The guns listed in the document are the XM150, which was the longer barreled version of the 152mm gun/launcher hybrid intended for the MBT-70, the M68 105mm gun that equipped the other versions of the M-60, the 120mm T123E6, a smooth bore cannon developed by the US but never put into production, and the British 120mm L11A2 cannon that was featured on Chieftain. I thought this was worth sharing, I have uploaded the relevant pages of the document here. Hopefully someone may find this information useful or at least interesting.

Thanks for uploading that, I already downloaded it successfully. My interest in this and any other documents you have links to or can transmit relates to having myself having reported to AMC (Test and Eval Cmd.-Armor Board) and was on the Initial Production Test Project for the M60A2. I also have an in-state contact who was at the Board before I was and was on the M60A1E2 project. Anything I can obtain would be much appreciated and would be shared with my colleague (who was also on the M551 project mid-late '60's). Thx in advance. You can PM me if we need to use other means for communication.

Glad you found it interesting! The complete Book is rather large, over 150 pages which is more than I can scan at home on my crappy little HP printer/Scanner. I may have to sneak it into work and use the big scanner there. This book is the only thing I have specifically on the M60A2. It was given to me by a friend that spent years working for the manufacturer of the M-60 engine. If I get around to having it scanned, I'll post it here. Thanks!

Doug_Kibbey

If we're safely in non-copyrighted material, that would be great! Thx.

Walter_Sobchak · ***Power User*** Offline Joined: Feb 20, 2013 Posts: 122

Doug_Kibbey wrote:

If we're safely in non-copyrighted material, that would be great! Thx.

Hmm, that's a fair point. Do 40 year old government documents fall under copyright laws? I mean, it's not like I am trying to sell them and they do, ultimately, belong to the tax payer. I would think it falls under "fair use" as long as its not something that is classified.

Doug_Kibbey

Walter_Sobchak wrote:

Doug_Kibbey wrote:

If we're safely in non-copyrighted material, that would be great! Thx.

Hmm, that's a fair point. Do 40 year old government documents fall under copyright laws? I mean, it's not like I am trying to sell them and they do, ultimately, belong to the tax payer. I would think it falls under "fair use" as long as its not something that is classified.

Is one even claimed? It will so state. In the U.S., it's:

95 years from publication for works published 1964–1977; 28 (if copyright not renewed) or 95 years from publication for works published 1923–1963 (Copyrights prior to 1923 have expired.)

Probably a public domain document if never offered for sale, which I gather is not the case. And you can be assured that the classified status (which was Secret at the time) is definitely past it's "use by" date. (Much as myself) Laughing

bsmart

If it was produced by the U.S. Gov't it is in the public domain. The only exception is documents produced for the gov't by copying manufacturers documentation to support a specific contract. Those documents are specifically marked as such (The main case I know of is computer manuals)

So if the document is a U.S. Government produced document it is free of copyrights. If it was produced by the vendor it should have a copyright or proprietary information statement on it

As a disclaimer - I am not a lawyer or a copyright specialist. I have done some research into the subject (Like when we had a problem here a few years back) and believe that I have provided an accurate layman's interpretation of the rules. Your mileage may vary and if you are caught just remember not to drop the soap Shocked

in the prison showers

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