Many of the Monday Morning Quarterback letters deal with federal retirement. Most come from feds who think the media and politicians have it in for them. But there are others, from people who do not work for the government, who see it another way. A couple of examples today. In another letter a government worker who says he is a former "beltway bandit contractor" tells why he is going back to his old trade. Here goes:

*"Your column of Sept. 25, 'Study Disputes Myth of Retiree Gravy Train,' prompted me to write. Was the congressional study done at taxpayers expense? Yes . The propaganda government workers generate is nauseating.

" . . . Federal and military workers have the best retirement plans going. The age they can retire, the percentage of salary they get, plus regular cost-of-living adjustments, make the average private pension plan look sick.

"Working . . . with a Fortune 500 firm for 20 years, my retirement at age 65 would have been between 8 percent and 10 percent of salary, with no cost-of-living escalations. I contributed 6 percent to the pension fund.

"Why don't government workers and military personnel have the decency to keep quiet and stop insulting the intelligence of people in the private sector who pay the lion's share of government retirement benefits? As for the military, we pay all of it.

"When government personnel do studies . . . they compare their plan with a few select corporations or to what the chairman of the board gets. Corporations must show profits to have any kind of plan. Tell your civil service friends the truth: They have a good thing going, and if they push too much they may end up like the greedy air traffic controllers' union.

" . . . You cannot be blind. You must see the great number of military and government personnel who are double and triple dippers. Some of these people are friends, receiving two or three checks monthly from the government, with incomes of $60,000 a year. How many private sector people do you know who are making more in retirement than when they held a job? It only happens to government people.

" . . . I have another 5 years to go to get the bulk of my retirement money, which I hope I can live on. I resent paying taxes to support early retirements and above average pension plans for people who generate no profits, and scream for more.

"I wish I could sign my name, but it would be social suicide. Smarten up your friends." Unhappy Taxpayer in Northern Virginia.

*Another writer, an employe of the W.R. Grace Co. in Columbia, also takes issue with the congressional report. It said that a number of firms, including Grace, have better pension benefits and that Grace employes can retire on 90 percent of salary. "I wonder what division of the W.R. Grace Co., gets 90 percent of salary in retirement benefits?" he asks. "It certainly is not my division. We might get 56 percent after more than 30 years."

*"Why do you always write about people who are Grade 15, and always mention their salaries? There are hundreds of us who served from 25 to 40 years at Grades 4, 5 and 6. I started at $2,450 per year. After 27 years I reached GS 5, something over $10,000.

"My retirement pays the rent, and I am grateful for it. But I look on it as my money, since I had paid into the retirement fund for 27 years. I resent having federal retirement referred to as welfare or a gift from the president. I am proud of my service. I worked for what I receive." Retiree in DC.

*"I hate Mondays except that it gives me a chance to read the quarterbacks sounding off. I loved the letter from the Lexington Park man who talked about government contractor benefits. But he left out some that we civil servants don't get.

"I was a contractor several years ago before coming back to government. As a contractor I made better money with more benefits, but thought I could rely on 'job security' in the government . . . . Besides higher pay raises and free medical insurance, the average contractor gets free life insurance and parking. I pay $80 a month to park in Rosslyn. The contractor who works for us gets free parking under our building. High, dry, fat and happy. It appears President Reagan will win again. Bottom line is, I'm going back to the beltway and become a bandit again. I can't afford not to." D.C. in Vienna.