According to the Maryland based pro-RKBA newsletter called "Tripwire", the program to date has cost at least $5 million and has not lead to one conviction. Supposedly, two crimes have be solved as result of the ballistic fingerprinting, but what is the point if you cannot get a conviction.
The "two crimes solved" statistic comes from Montgomery County State Attorney Doug Gansler, and I would not trust anything he says. He is not a friend of RKBA.