THE 1975 MASSACHUSETTS MANDATORY GUN LAW, KNOWN AS THE (BARTLEY-FOX LAW), REMOVED JUDICIAL DISCRETION AND WAS DESIGNED TO HALT THE DRIFT TOWARD LENIENT SENTENCING. THE LAW IMPOSED A MANDATORY 1-YEAR SENTENCE FOR UNLICENSED PERSONS TO CARRY A FIREARM AWAY FROM HOME OR PLACE OF BUSINESS. THE RESULTS OF A 2-YEAR STUDY OF THE LAW ARE DISCUSSED. IT RELIED ON CRIME STATISTICS FROM THE FBI AND THE BOSTON POLICE DEPARTMENT, ARREST REPORTS FROM THE BOSTON POLICE DEPARTMENT, COURT RECORDS, AND INTERVIEWS WITH CRIMINAL JUSTICE PERSONNEL. A SUMMARY OF THE MAJOR FINDINGS CONCLUDES THAT THE INTRODUCTION OF BARTLEY-FOX HAD AN IMPACT ON THE CRIME RATE, REDUCED THE INCIDENCE OF GUN ASSAULTS, AND PROBABLY HAD THE UNANTICIPATED EFFECT OF INCREASING CITIZENS' CRIME-REPORTING BEHAVIOR. THE LAW HAD A MODERATE DETERRENT EFFECT ON THE ARMED ROBBERY RATE, BUT POLICE OFFICERS WERE CONFUSED ON HOW OR IF THE LAW APPLIED IN A GIVEN SITUATION. NO EVIDENCE EXISTS TO SUGGEST A RACIALLY DISCRIMINATORY PATTERN OF BARTLEY-FOX ENFORCEMENT. GUN HAND-INS INCREASED. SEVERAL QUESTIONS ABOUT CHANGING DECISIONS AND THE MANDATORY SENTENCES ARE ALSO RAISED. FOR INSTANCE, IN SOME CASES POSSESSION OF A WEAPON RATHER THAN CARRYING IS CHARGED TO AVOID THE MANDATORY SENTENCE. OTHER FINDINGS SHOWED THAT THE TOTAL NUMBER OF GUN-CARRYING CASES DECLINED; THE PROPORTION OF DEFENDANTS WHO WERE CONVICTED OF ILLEGALLY CARRYING A FIREARM DECREASED, BUT THE PROPORTION OF THOSE WHO RECEIVED SOME JAIL SENTENCE INCREASED. THE LAW PROMOTED SOME UNIFORMITY IN RULINGS IN THE DISTRICT COURT SYSTEM; PLEA BARGAINING CONTINUED TO PLAY AN IMPORTANT ROLE IN DISPOSING OF BARTLEY-FOX CASES IN SUPERIOR COURT, AND GENERALLY, JUDGES AND PROSECUTORS BELIEVED THAT THE LAW DID NOT PERSUADE THE CRIMINAL JUSTICE SYSTEM TO 'GET TOUGH' WITH VIOLENT CRIME. NO REFERENCES ARE PROVIDED. (RFC)