When Did The US Marines First Get M60A1's?

I know about the practice of giving them modern equipment last. I did see the thread which mentioned they were the last to get rid of their M48 series tanks. But when did they start getting newer equipment in the first place?

They started getting M1A1’s not to long before Desert Storm in 1990. In Desert Storm Marines had Both M1A1,s and M60A1’s in theater.

It looks like 1976/1977 when the RISE package was fielded.

The thread did mention that M48 tanks were all replaced in the USMC in the early 1970’s by the M60A1’s. I was wondering when the process started though. All at once?

Active duty receives equipment first and then they start integrating into the reserves.They do not all swap at one time. There is an orderly progression.Training must happen with the changeover and training is limited to the number of trainers, seats available and training location availability.