WITH THEIR SLENDER BUTTS and cute little muzzles, they look like toys. One flick on the trigger and out barks one-third of an ounce of lead at 700 miles per hour, shaped to plow a mushroom cavity into someone's gut. Beyond the range of a card table they are inaccurate, so they are little use to hunters and target shooters. Their sole advantage is that they leave no unsightly bulges when they are concealed. In gun magazines they are called "snubbies."

Handgunds of all sizes were instruments of 10,000 murders and another 550,000 crimes of violence in 1977. There are about 50 million handguns in circulation. So in a given year, one out of every 100 handguns in the nation's private handgun arsenal is involed in a crime. Based on the findings of our computer analysis of more than 14,000 handguns used in crimes during 1979, that one gun is very likely to be a "snubbie."

This conclusion, drawn from an investigation by four reporters in the Cox Newspapers Washington bureau, may point to a way out of the impasse in the national debate over handgun control. Neither side in the debate has been willing to take a microscopic look at what sorts of guns actually are used in crime.That is exactly what my associates and I have tried to do.

Contrary to popular impression, most street crime guns are not cheap, low-caliber, foreign-origin "Saturday Night Specials." When we compiled a list of the 15 leading crime handguns, we were surprised to find that only two fit that exact description. Ten of the 15 were made in American factories out of American-made components. Of these 10, seven were made by Smith & Wesson, Colt and Charter Arms, all makers of high-quality, relatively expensive guns.

Above all, criminals seem to prefer concealability. Of the 15 leading crime handguns, 11 had snub-nosed barrels measuring 2.5 inches or less. Four of these "snubbies" were expensive, well-made American guns. Three others were low-budget specials also made in America. The remaining four were inexpensive weapons assembled by small plants in Miami from sets of gun parts shipped in from Italy and Germany.

We found that one of the Miami-assembled imports -- the Roehm .22-caliber revolver -- was the country's single leading crime instrument. In 1979 one out of every 12 handguns traced in a street crime case was a short-barreled Roehm .22. It is a "Saturday Night Special" by anyone's description, typically retailing for $39.95. It is assembled in a Miami warehouse by the German-owned RG Industries Inc. out of gun parts shipped from its West German affiliate, Roehm GmbH. President Reagan was wounded with the best-selling Roehm .22, the RG14, last spring.

The second-ranking crime handgun was the snub-nosed Smith & Wesson .38 caliber Chiefs Special. Advertised as a police "backup" weapon, the Chiefs Special is also sold to civilians through sporting goods stores for prices ranging from $170 to $240. Imagine a gun slightly less than half the length and weight of a traditional Colt Six-Shootter. That's a Chiefs Special.

Both the Roehm-origin .22 and the Chiefs Special are examples of guns that are statistically more prone to crime than the average handgun. About 4 percent of the handguns in the United States are Roehm-origin .22s. But our study found they represented 7.9 percent of handguns traced by police at crime scenes. Similarly, Smith & Wesson's light-framed "snubbies" -- the standard Chiefs Special and its several variants -- make up no more than 3 percent of the handguns in the United States. But they turned up in 5.9 percent of street crime cases in which a handgun was traced.

Small handguns have been favored for big name shootings as well as for humdrum crimes.

President Ford was nearly assassinated in 1975 when Sara Jane Moore pulled the trigger of a Chiefs Special and missed. Mayor George Moscone of San Francisco was killed with a Chiefs Special in 1978. A year ago, Washington cardiologist Dr. Michael Halberstam was also killed with a Chiefs Special. Former Alabama Gov. George Wallace was paralyzed by a Charter Arms Undercover in 1972. Former Beatle John Lennon was murdered by an Undercover in 1980.

Checking in historical archives, we found that since 1835, the weapons used in 10 out of the 15 assassination attempts on major American political figures were among the most readily concealable varieties of pistols then on the market.In addition to Reagan, Ford, Wallace and Moscone, Andrew Jackson, Abraham Lincoln, William McKinley, Franklin D. Roosevelt, Huey Long and Robert F. Kennedy all were fired at with smaller-than-normal handguns.

The size of a handgun is only one indicator of its criminal tendencies. Recently purchased guns of all sizes are more likely to be found at crime scenes than older guns. A tabulation by the Treasury's Bureau of Alcohol, Tobacco and Firearms shows that 18 percent of the crime guns traced in 1979 were a year old or less. The next largest category was two-year-old guns, representing 10 percent of the crime guns. After that, the percentages trailed off year by year -- 6 percent of the crime guns were eight years old, 4 percent nine years old and so on. It was almost as if guns exuded a radioactive half-life as crime instruments.

What comes out of all this is that some kinds of handguns -- newly acquired ones, and those which can be readily hidden -- are more prone to crime than others.

This disparity in criminal tendencies is wide enough to raise questions for those on all sides of handgun control controversy.

For the ban-the-handgun crusaders: Instead of tilting at all handguns, why not concentrate on restricting those kinds of guns that are statistically shown to be crime-prone? Isn't a criminal record the best measure of whether a certain kind of gun should be freely sold?

For people who like to shoot handguns: Why fight to preserve palm-sized handguns when they aren't ideal for shooting burglars and they are almost useless for hunting and target practice? Why defend the right of fast-buck assembly plants to import gun parts and slap them together to make handguns that no hobbyist would want to fire?

Clearly, the old familiar gun control proposals -- registration, licensing, waiting periods for gun purchases -- are going nowhere in Washington. If there remains any emotional bridge that joins the pro-gun and anti-gun people, it is that they are all against crime. That may turn out, in the long run, to be more important than it sounds.

In the 1920s almost everyone came to the conclusion that machine guns had no redeeming social value for civilian use. The result was the National Firearms Act of 1934, a law which passed Congress because it split the gun issue in two. It left handguns alone. And it clamped down hard on "gangster-type weapons" such as machine guns, sawed-off shotguns, fully automatic rifles and silencers.

The National Firearms Act, which is still in effect, allows citizens without criminal records to own machine guns -- if they have written permission from federal and local authorities. Each "gangster-type weapon" must be registered with the federal government, and a $200 transfer tax is due to the Treasury any time one is sold.

Based on the criminal record of snub-nosed handguns, people on all sides of the gun control issue have to wonder whether "snubbies" have earned the same treatment as machine guns.