OIG asked how often there was a discrepancy between the inventory and what the NFRTR said the inventory should be: 46% of inspectors said either “always” or “most of the time.” (Only 5% reported “never”).
I’ve heard this from ATF people who have spoken at the National Firearms Law Seminar too. The database is a mess, and there’s been a quiet effort to clean it up going on for years. Dave also notes:
Mind you, felony prosecutions are undertaken relying on the NFRTR to establish that a gun is not registered, and with evidence consisting of an affidavit from the custodian of records for the NFRTR certifying that no record of registration could be found.
But don’t go thinking you’ll evade prosecution if you convert your AR because the NFRTR is flawed. Most machine gun prosecutions there days proceed under 18 USC 922(o), where all they have to do is prove the machine gun was manufactured after May 19th, 1986, and that you possessed it. But if grandpa kicks the bucket, and you find the M1 Thompson he managed to smuggle back from Europe, be sure your lawyer knows the history of the NFRTR.