Illegal possession of a firearm carries up to 15 years in federal prison for a prohibited person, and mandatory minimums can push the sentence for illegal possession of a firearm significantly higher based on criminal history and how the weapon was used. The actual number depends on who had the gun, what kind of gun it was, and whether the case is charged federally or at the state level. Federal time hits harder because there is no parole in the federal system; defendants serve at least 85 percent of whatever the judge imposes.
The 15-Year Federal Ceiling
The base federal penalty for a prohibited person caught with a firearm is up to 15 years in prison.1Office of the Law Revision Counsel. 18 USC 924 – Penalties Fines on a felony firearms conviction can reach $250,000.2Office of the Law Revision Counsel. 18 USC 3571 – Sentence of Fine
Fifteen years is the ceiling for the straightforward charge, not the typical outcome. Where a case actually lands depends on the defendant’s criminal record, the weapon involved, the number of firearms, and whether the gun played a role in another offense. First-time defendants with no violent history generally see sentences well below the maximum. Defendants with the wrong combination of prior convictions can see 15 years as the floor rather than the top.
Mandatory Minimums That Raise the Floor
Two federal enhancements do most of the work in pushing sentences past the base range. Both strip the court’s discretion to grant probation or a suspended sentence.
The Armed Career Criminal Act
The Armed Career Criminal Act imposes a 15-year mandatory minimum on anyone convicted of illegal firearm possession who has three or more prior convictions for a violent felony or serious drug offense, with those priors occurring on separate occasions.3Office of the Law Revision Counsel. 18 USC 924 – Penalties The court cannot suspend the sentence or grant probation under the ACCA. This is where prosecutors have the most leverage in plea negotiations, and where a defendant’s record carries the most weight.
Using a Firearm During Another Crime
When a firearm is used during a violent crime or drug trafficking offense, 18 U.S.C. § 924(c) adds mandatory prison time on top of the sentence for the underlying crime:
- Possessing a firearm in connection with the crime: 5-year mandatory minimum.
- Brandishing the firearm: 7-year mandatory minimum.
- Discharging the firearm: 10-year mandatory minimum.
These sentences run consecutively, served after the sentence for the underlying crime rather than at the same time. Probation is not available for a 924(c) conviction, and concurrent sentencing is off the table.3Office of the Law Revision Counsel. 18 USC 924 – Penalties A defendant convicted of drug trafficking who brandished a firearm will finish the drug sentence and then start a separate seven-year term.
How Guidelines Translate the Case Into Months
Federal judges follow the U.S. Sentencing Guidelines, which are advisory but heavily influence outcomes. Two inputs drive the recommended range: the offense level and the criminal history category.
For firearms offenses, the base offense level under Section 2K2.1 depends on the defendant’s prior record and the type of weapon. A defendant with two or more prior felony convictions for violence or drug offenses who possessed a semiautomatic firearm capable of accepting a large-capacity magazine starts at offense level 26. One such prior with a similar weapon starts at 22. The level drops for defendants with lighter histories.4United States Sentencing Commission. USSG 2K2.1 – Unlawful Receipt, Possession, or Transportation of Firearms or Ammunition
The number of guns matters. Possessing three or more firearms triggers an automatic increase in offense level, and the increase grows with the count. Only firearms unlawfully possessed or distributed count toward the total.5United States Sentencing Commission. Primer on Firearms Offenses
The spread between a clean record and an aggravated one is large. A first-time offender with no violent history might face a guideline range in the area of 15 to 21 months. A defendant with a violent felony history and an aggravating weapon type could be looking at 70 to 87 months or more on the same basic charge.5United States Sentencing Commission. Primer on Firearms Offenses Judges can depart from the range, but most sentences land inside it.
Charges That Stack On Top
Possession cases rarely arrive as a single charge. Several related offenses carry their own penalties and get added to the main count.
Unregistered NFA Weapons
The National Firearms Act requires registration and a tax payment for machine guns, short-barreled rifles, short-barreled shotguns, and silencers.6Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). National Firearms Act Possessing any of these without proper registration is a federal crime punishable by up to 10 years in prison and a fine of up to $10,000.7Office of the Law Revision Counsel. 26 USC 5871 – Penalties
Obliterated Serial Numbers
A firearm with a removed, altered, or obliterated serial number is a separate federal offense carrying up to five years in prison.3Office of the Law Revision Counsel. 18 USC 924 – Penalties This charge frequently rides along with the main possession count.
Gun-Free Zones
Possessing a firearm in a federal building, airport, or in or near a school is prohibited by federal law. The Gun-Free School Zones Act carries up to five years in prison.3Office of the Law Revision Counsel. 18 USC 924 – Penalties
Straw Purchasing and Trafficking
The Bipartisan Safer Communities Act of 2022 made straw purchasing and firearms trafficking standalone federal crimes. Buying a firearm for a prohibited person, or for someone you know plans to use it in a crime, carries up to 15 years in prison.8Office of the Law Revision Counsel. 18 USC 932 – Straw Purchasing of Firearms If the trafficked weapon ends up used in a violent felony, terrorism, or drug trafficking, the maximum climbs to 25 years.9Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Don’t Lie for the Other Guy
Federal vs. State Charges
Illegal firearm possession can be charged in state or federal court, and the forum changes the number. Federal cases typically result in longer sentences, no parole, and tighter sentencing rules.
Several factors push a case federal:
- The firearm crossed state lines at any point, triggering interstate commerce jurisdiction.
- The person is prohibited under federal law.
- The firearm was possessed on federal property.
- The gun was used during a federal crime like drug trafficking.
Federal law applies uniformly across the country and is often more restrictive than the equivalent state statute. At the state level, felon-in-possession charges generally carry mandatory minimums ranging from about one to three years, depending on the state. State rules vary enough that anyone facing a state charge needs to check their own jurisdiction’s framework.
You Do Not Need the Gun On You
Possession for sentencing purposes is broader than most people assume. Federal prosecutors regularly bring cases based on constructive possession, meaning the defendant knew about the firearm and had the ability to control it. A gun in your glove box or hidden in a closet in your home can support a charge if the government can show awareness and access.
The limits matter. In United States v. Bailey, a court held that the mere presence of a firearm in a borrowed car was not enough on its own to establish constructive possession by the borrower. Prosecutors need evidence of both knowledge and the ability to exercise control. The distinction becomes decisive in shared apartments and vehicles.
What Comes After the Prison Sentence
The sentence does not end at release. Federal firearms defendants face supervised release of up to three or five years depending on the severity of the offense.10Office of the Law Revision Counsel. 18 USC 3583 – Inclusion of a Term of Supervised Release After Imprisonment Conditions include regular check-ins with a probation officer, drug testing, and home and workplace visits. Officers can seize prohibited items found in plain view and may be authorized to search the person, home, or vehicle at any time.11eCFR. 28 CFR 2.204 – Conditions of Supervised Release A violation can send someone back to prison.
A federal firearms conviction permanently strips the right to own or possess any firearm. It can also cost the right to vote, serve on a jury, and hold public office.12Department of Justice. Federal Statutes Imposing Collateral Consequences Upon Conviction Employment options narrow because many employers and licensing boards disqualify applicants with felony convictions.
For non-citizens, a firearms conviction is close to the worst possible outcome. Federal immigration law makes any person convicted of a firearms offense deportable, regardless of the weapon or the length of sentence.13Office of the Law Revision Counsel. 8 USC 1227 – Deportable Aliens Lawful permanent residents who have lived in the United States for decades are not exempt. Even a misdemeanor firearms conviction can trigger removal proceedings.