This is from the FBI Gun Laws and NICs Information Center site:
If you believe you have been erroneously denied a firearm transfer based on a match to a record returned by the National Instant Criminal Background Check System (NICS), you may request an appeal of your deny decision. The provisions for appeals are outlined in the NICS Regulations at Title 28, Code of Federal Regulations, Part 25.10, and Subsection 103 (f) and (g) and Section 104 of theBrady Handgun Violence Prevention Act of 1993.
You may request the reason for your denial by writing to:
Federal Bureau of Investigation
Criminal Justice Information Services Division
Appeal Services Team, Module A-1
Post Office Box 4278
You must include the required information (listed below) along with your appeal request:
1. FULL NAME
2. COMPLETE MAILING ADDRESS
3. NICS TRANSACTION NUMBER (NTN) or STATE TRANSACTION NUMBER (STN)
Failure to submit all required appeal information may result in the rejection of your appeal request.
An Official FBI Fingerprint Card is included. The submission of your (rolled or a hard copy of your electronically scanned) fingerprints may help accelerate the appeal process. NOTE: Appeal Fingerprint Cards are not accepted via facsimile.
The NICS Section’s Appeal Services Team (AST) will respond to your initial appeal request by providing you with the general reason for denial within five business days.
Appealing your Denial
The following information outlines the steps you must take to either challenge your record or make a claim the record used as the basis for your denial does not pertain to you.
Questions of Identity
In cases involving criminal history records, if fingerprints are not submitted along with your initial appeal request, you may subsequently be required to submit your fingerprints to establish positive proof of your identity. If your fingerprints are required by the NICS Section and you wish to further the appeal process, you must have your fingerprint impressions rolled or electronically scanned by law enforcement or another authorized fingerprinting agency. The agency preparing your fingerprints must provide an agency name, address, telephone number, and an Originating Agency Identification number (as assigned by the FBI) and the legible signature of the person who rolled your fingerprints on the fingerprint card. The reason fingerprinted should be marked “For NICS Purposes.” The omission of any required information (as listed above) may result in a rejection of your fingerprint card.
NOTE: Specific appeal information can only be provided to you once positive proof of identity has been established via the submission of your fingerprints.
You may challenge the accuracy of the record used in the evaluation of your denial or declare your rights to obtain a firearm have been restored, etc. If you have additional information (e.g., court documentation) to assist the AST in correcting or updating the record, you should include the information with your written correspondence.
If the AST is unable to resolve your appeal, you will be provided referral information to contact the agency maintaining the record. For correction of the record, you must follow procedures established by the state or federal agency maintaining the original record. You may submit any information to the originating agency to assist with the correction or update of your record. (This may also help accelerate the appeal process for you.) If the originating agency corrects your record, the AST must be notified and provided documentation indicating such. The AST will evaluate and verify the information and provide you with a decision on your appeal in writing.
All appeal inquiries must be directed to the AST in writing. Due to the Privacy Act of 1974, specific information cannot be disseminated to you via the telephone.
If your appeal is successful, you will be notified by the AST, via U.S. mail, your denial has been overturned and you currently have no firearm prohibitions. You will be issued documentation which must be presented to the Federal Firearms Licensee who initiated your background check.
Please let me know if you have any other questions or you need me to clarify anything. Please also submit a rating if you're satisfied with your assistance; this will not cost you anything extra. We only get credit for the time we take assisting you if you are satisfied AND ALSO submit a rating. And please don't feel like we have to stop talking after you submit a rating. I'd be more than happy to continue working with you after that as well.
Also, the following is the Missouri Gun Law (so that you can verify you included everything you need to the first time... and in your next attempt):
Peaceable journey and RV law
Missouri has a "peaceable journey" under Missouri Statutes 571.030 which law says it is legal to carry the weapon in a passenger compartment of a vehicle as long as (1) the concealable firearm is otherwise lawfully possessed, (2) the person is 21 or older, or (3) the person is in his dwelling unit (e.g. RV) or upon premises over which the person has possession/authority/control, or is traveling in a continuous journey peaceably through this state.
The same applies (it is not a crime) when the person is 21 and possesses an exposed firearm for the lawful pursuit of game.
Missouri does allow open carry of firearms for those age 21 or older. However, city, county, and municipalities are allowed to pass laws and ordinances restricting this. It is advisable to check local laws and ordinances before openly carrying a firearm within Missouri.
Missouri Statute 571.070 (8/28/2007) says that unlawful for a felon (also a drunkard, drug user and adjudged incompetent Person) to have possession of any firearm (including concealable firearms). Violation of this law is a class C felony.
Missouri Statute 571.121 (8/28/2007) says (a) you have to carry permit with you when you carry the concealed weapon and if you don't have it with you, it's not a crime, but you can be fined up to $35, and (b) director of revenue issues a driver's license or a state I.D. with a CCW endorsement that reflects that you can carry concealed.