Clarification
From what I see you made a plea deal that actually means you plead guilty to a felony conviction. That conviction was set aside after you completed the terms of your probation, BUT it is still a conviction. You should get an attorney and get it expunged if you can show you have changed your ways. But it still is a conviction but will not show on records, and you could get in trouble for not divulging it on state and federal forms.
Depending on your current state you may be able to purchase cap and ball revolvers without any check and may be legal for you to own. I am not so sure about OCing though. You probably would still get arrested if challenged by a LEO, then it would be up to the court to decide if you had the right to bear arms with a felony conviction.
Check your state laws.
I Just wanted to clarify the law here.
When one enters a deferred prosecution where the charges are to be "dismissed" (with or without prejudice) -- there is NO, ZERO "Conviction".
When someone does a Deferred prosecution, ie: A drug court for example. The charge and case(s) are placed on administrative docket to be Adjudicated on the time and date stated when one is accepted into the "Deferred Prosecution". This means in laymans terms the charge is placed on HOLD for however long the period is the individual has to go through and if said individual complies with the terms that are clearly stated in the acceptance of the Deferment -- they will end up with a DISMISSAL of the charge.
In these cases , again, there is no conviction. You are not entered as guilty, or not guilty. The matter is dropped/dismissed entirely. Therefore a person is not only not a felon they do not have a felonious charge on their record.
I know legal terms can be misleading or hard to understand but the biggest benefit of these types of generally extremely difficult and lengthy deferred programs is to give non-violent offenders (generally first time offenders) an opportunity NOT to screw up their liberties, rights, and become "Felons". They get an opportunity through hard work, ALOT of the courts running their lives for a year or longer to eventually upon 'graduation' of said program to be just as they were prior to acquiring the charge. A free person,.. not as if they served a sentence and were on parole, but the charges dismissed.
People who take a deal and plea guilty and do NOT go to jail or prison but are placed on probation are an entirely different matter. In these cases the prosecution was NOT deferred it was adjudicated then and the guilty plea taken and judged upon as guilty of the crime, then they were placed on probation as their sentence. These people are "felons".
This applies in all states -- A deferred prosecution that results in dismissal of the charge(s) = no lost rights, including the right to bear arms, which specifically allows the purchase of firearms. A background check may show the arrest,.. but will note the charges were dropped.
This would be equal to a person with a felony charge going to a trial, and being found not guilty by the jury -- The background check would still show the arrest and the not guilty verdict. Sometimes these things are worded in the database as Charge: AD-HOC.
In some cases, the individual DOES plea guilty and is sentenced to X years in prison -- however the matter is still placed on deferment and if the individual completes the program successfully this sentence is removed and charges , again, dropped. Resulting in no conviction.
There cannot be a conviction AND a dismissal of charges of a felonious nature.
I'm glad you had the opportunity to retain your rights, and absolve yourself of these charges. It is/was the right thing to do.
Any violent act, even remotely violent (ie: Assault/battery) or more serious drug offenses like intent to distribute will not qualify, and the background check would fail due to such charges.
Though again, any deferred charge that is ultimately 'dismissed' never was indicted or convicted. It is permanently (if dismissed WITH prejudice) eradicated and unable to be tried or brought up again in the judicial system.
Take care,