Permit me to add a few observations to "Arms and the Congress: Anti-Tank Weapons" {news story, June 13}. The Gorbachev-catalyzed world is moving away from heavy offensive military forces and toward "defensive defense." This requires reducing the number of tanks and increasing the effectiveness of antitank weapons. There can be no better deterrent to armed invasion than a large number of missiles light enough to be carried and concealed by one man but powerful enough to stop any tank from any angle.

Our present weapon, the Dragon, is hopelessly inadequate. It weighs 73 pounds and lacks range and smoke-penetrating ability. It cannot penetrate the advanced armor that will adorn most of the world's tanks within the next few years. It can't be fired from a standing or prone position or from within an enclosure. An even greater deficiency is Dragon's requirement that its operator sit exposed and motionless guiding the missile while every enemy in sight is pouring fire at him.

The U.S. Army and Marine Corps are in final development of an advanced 45-pound weapon, called AAWS-M, which cures all these problems and has performed well in tests. But it won't be in the force for several years.

As a stopgap or possible replacement for the new device, two European manufacturers are trying to sell us their own obsolescent 118-pound antitank models, which share all the deficiencies of Dragon except range. To gain visibility, these concerns are lobbying heavily for a multimillion-dollar test of their weapons against Dragon. The Army and Marines oppose such a test, as do I.

Our opposition is not, as the article suggests, based on "fear that a test would show that {the European weapons} are superior." Rather it is based on the fact that a test could only show that the European weapons offer longer range at the price of an unacceptable weight increase. We already know that, and there is no reason to spend taxpayers' money demonstrating the obvious. LES AuCOIN U.S. Representative (D-Ore.) Member, defense appropriations subcommittee Washington