Hi Suhiir -
You're right, per
T-34-85 VS M26 PERSHING Korea 1950 by Zaloga, on pp.46-47 it states that the Marines had received 102 M26 Pershings from the Army, and all but H&S Company continued using the M4A3(105)s for training, the crews cycling through H&S Co to keep current on the M26; the rest were indeed in storage at Barstow depot. A Company, 1st Tanks was the only active company of the battalion, so they had to scramble to collect experienced tankers from around the country to reconstitute the entire battalion. They got 27 M26s loaded on LSDs for the trip to Pusan, 22 for A Co and 5 for the regimental AT platoon (H&S Co crews filled out the AT platoon). They didn't send any floaters, and 90mm ammo was tight...a situation exacerbated by partial flooding on two LSDs (different source, may have been the 1st Tanks history site), the well decks suddenly began to flood while the ships were under way, and several tanks with 90mm ammo on board were flooded. The tanks were dried out and cleaned, but the ammo on those tanks were ruined and had to be replaced.
The earliest photo evidence of USMC M46s I found was in Hunnicutt's
PATTON, dated 23 November 1951; others are seen "ridge running" during the winter of 1951-52. Other sources were more vague, saying they were reequipped "after the Chinese spring offensive", which was in late May 1951. The front line stabilized on the Jamestown-Missouri-Minnesota line by November 1951, and the Army took the opportunity that month to reorganize their tank units to the 69-tank standard battalions, and organizing regimental tank companies that were missing, so it is likely that the Marines took that opportunity to field M46s. Somewhere I had read that the Marines only received 80 M46/M46A1s, which is barely enough for the division...if true, then I assume that UNC took care of maintenance float?
Not likely...
Since 1st MarDiv retrograded from Korea around March 1955, it is most likely that they were reequipped with M48A1s after returning to Pendleton.
M47 production was insane...while production nominally began June 1951, they didn't enter testing until late August, and that ran for a year. The early deliveries didn't even have the rangefinder installed, just like the T48s. While few automotive bugs were found, the problems were mostly related to the turret fire controls...it was designed to use an IBM gun stabilization system, but DA deleted the stabilizer and didn't redesign the FC to compensate...it took a year to work those bugs out. Meanwhile both Detroit and ALCO were cranking out incomplete tanks at a combined rate of around 350 tanks per month (estimate 210 Detroit starting October 1951, 140 ALCO starting late January 1952).
Re: M67, the Marines got the M67 based on the M48A1, the Army got the M67A1 based on the M48A2. The M67 was standardized on 1 June 1955, the M67A1 on 8 January 1959. M67s had .30cal coax MG; the M67A1 had 7.62mm M73 coax, improvements to the gun shield, and Cadillac Gage fire controls. 35 Marine M67s were authorized for dieselization late 1961; one pilot conversion at Detroit arsenal included upgrading the turret to M67A1 standards (coax, gun shield, FC), was designated M67E1 on 1 February 1962. M67E1 standardized as M67A2 on 25 June 1962; 73 remaining M67s converted at Anniston to this standard in parallel with M48A3s. The Army put its 35 M67A1s in storage by 1963, replacing them with cheaper M132 Zippo tracks; they were given to the Marines and dieselized to M67A2 standards by 1968, but they retained the three track return rollers, the M67/M67A2s had five. So the Marines received a total of 109 flamethrower tanks.
Re: mine rollers, that's what I gather, only experimental mine rollers were being tested on M48A1s, none fielded. After WWII, they scrubbed the Aunt Jemima mine roller and all flails and plows. They actually tried mounting several rockets on the glacis of tanks, with the jet blasting downwards, but it raised too much dust and wasn't very effective. During the Korean War, they sent this comb-shaped monstrosity called High Herman with 25 one-ton spoked disks to be fitted to the M46, but the thing weighed 36 tons, the mounting arm got in the way of the main gun firing forwards, and it tended to blow the final drive on the poor tank. So by 1953, they revised the mounting to two arms, and reduced it to 16 disks individually articulated, eight in front of each track, called Larruping Lou. Later reduced to 12 disks, six per track, this weighed 20 tons and didn't kill the final drives as much. But by May 1954, DA wanted a lightweight expendable roller, so US Army Engineer and Research Development Laboratory (ERDL) came up with two individual arms with a steam-roller-like solid roller in front of each track, called ERDL I. While effective, they replaced the solid rollers with four individually sprung tank road wheels, called ERDL II; this looks a lot like the ENSURE 202 that got fielded. DA contracted with Birmingham Fabricating Co to make the ERDL II, but they increased the number of road wheels to six per arm, twelve total. Now there was a concern that these lightweight rollers weren't providing sufficient ground pressure to set off antitank mines, so Lockley Machine Company came back with big solid drums with spikes on it, with arms that would shift more of the tank's weight on the rollers, but that tended to overstress the rear suspension on the tank, and was too expensive and not expendable. When the Vietnam War began, DA went back to the Birmingham roller, redesigned the mounting arms, and it was accepted under the Expedited, Non-Standard, Urgent Requirement for Equipment (ENSURE) program as the 202nd article, so called ENSURE 202. It was of limited effectiveness, so disappeared after the war while they studied captured Russian KMT-4 mine rollers the Israelis got from various Arab armies. This was tested on M60 series tanks, and finally fielded along with the track-width mine plow during Desert Storm as the Battalion Counter-Mine System.
John