The Senate Armed Services Committee, perhaps the most pro-defense panel in Congress, yesterday voted to cut $9.9 billion from President Reagan's proposed Pentagon budget next year but refused to eliminate any major weapons system.

The panel's final proposal would allow manpower to grow by about 60 percent of the amount Reagan requested. The committee Wednesday rejected by one vote an amendment to cut personnel by 175,000 below current levels.

The committee action would reduce the president's $312.3 billion fiscal 1986 defense spending proposal to 3 percent growth after inflation. That is half the increase Reagan had sought.

Committee Chairman Barry Goldwater (R-Ariz.) said yesterday that he expects more attempts to cut the bill when it reaches the Senate floor.

"Defense spending has become a prime target of members of Congress," he told a news conference. "We'll be lucky if we can hold what we have."

During its three-day, closed markup, the committee also developed -- but did not recommend -- a bill that would provide for "zero growth" taking inflation into account, an approach that would require cutting $19.7 billion from the president's request. That approach froze military personnel levels for next year and eliminated the Army's problem-plagued Divad battlefield antiaircraft gun. Overall, however, that approach also slowed rather than eliminated major weapons-systems production.

Goldwater said yesterday that he "wouldn't stand still" for such a spending freeze, but that zero growth already has been approved by the Senate Budget Committee, and has since gained support in both houses.

Goldwater's committee voted 13 to 6 against a motion by Sen. Edward M. Kennedy (D-Mass.) to approve the zero-growth level. Democratic Sens. John C. Stennis (Miss.), Sam Nunn (Ga.) and John Glenn (Ohio) joined the Republicans in defeating the measure.

Yesterday, at a luncheon with Washington Post reporters and editors, Rep. Les Aspin (D-Wis.), chairman of the House Armed Service Committee, repeated his prediction that the House will approve zero-growth plus inflation.

As approved by the Senate panel, the bill would fund production of 21 additional MX intercontinental ballistic missiles (ICBM) but allow only 18 to be deployed in silos. This would effectively authorize 50 of the 63 MX ICBMs funded for deployment. The other 13 would be available only for testing. The first missiles are expected to be deployed in December 1986.

The committee statement yesterday said that "these actions should not be viewed as a 'cap' on deployment." Goldwater said he expects that the number of MX missiles approved for production next year "will get smaller" as the bill goes through Congress. Nunn is expected to offer an amendment on the Senate floor to cap deployment at 40 missiles.

The committee also:

* Reduced by $300 million the $3.7 billion request for the Strategic Defense Initiative (SDI), the "Star Wars" research program. Allocation of the cut would be left to the Pentagon. Sen. Carl Levin (D-Mich.), who failed to cut SDI by $1.4 billion in committee, said yesterday that the program "is throwing millions away" to U.S. and even foreign contractors, thus "trying to build a political base" for continued spending.

* Approved $163 million to prepare for initial production of updated chemical weapons, an administration proposal rejected by Congress in each of the last three years.

* Delayed a planned 3 percent military pay raise six months, from July to January, but approved 60 percent of the military active and reserve personnel increases sought by the president. On Wednesday, the committee defeated by one vote a proposal by Sen. Warren B. Rudman (R-N.H.) to cut Pentagon civilian and military personnel levels by 175,000 over two years. Rudman is expected to offer the amendment on the Senate floor.

* Adopted by a straight party-line vote a controversial amendment by Sen. Phil Gramm (R-Tex.) that would create a procedure for "emergency" base closings when the federal budget is in deficit. He linked the amendment to other language that would repeal or modify several longstanding laws that govern wages paid construction workers and other employes, including repeal of the Davis-Bacon Act for military construction projects. That act requires payment of prevailing union wages on federal contracts.

* Adopted a Levin measure to deal with military and Pentagon civilian employes who leave their jobs and go to work for defense contractors over whom they have had supervisory responsiblity. The proposal would require individuals to report all employment discussions with such companies while in service and then halt working on that company's contract. Failure to report such a contact would prohibit that individual from working for the company involved for two years.

* Reduced defense procurement next year overall by $4.6 billion, of which $2.8 billion came in tactical weapons programs. The reductions, however, were allocated to slow purchases of dozens of systems. The Divad air defense gun, for example, was cut $256 million to $150 million and the money withheld until the system successfully completes its operational testing.