Wisconsin 2025-2026 Regular Session

Wisconsin Assembly Bill AB321

Introduced
7/8/25  
Refer
7/8/25  

Caption

An Act to amend 939.6195 (1) (a) 1. and 941.291 (1) (b); to create 941.293 of the statutes; Relating to: prohibition against undetectable firearms, possessing a frame or receiver of a firearm without a serial number, and providing a penalty.

Summary

AB321 would create a new state crime addressing so-called undetectable firearms and unserialized firearm components. The bill defines an undetectable firearm as one that cannot be detected by a calibrated metal detector after removal of grips, stocks, and magazines, or whose major components do not produce an accurate image on airport-style security scanners or x-ray machines. It would make it a felony to sell, offer to sell, transfer, transport, manufacture, possess, or carry such a firearm, and separately criminalize the sale, posting, provision, or possession of plans to manufacture one. The bill also targets firearm parts by making it a Class I felony to possess a frame or receiver that is not attached to a firearm and is not marked or engraved with a serial number, subject to exceptions for pre-1968 frames or receivers and for certain official-duty law enforcement, military, and licensed manufacturing activity. In addition, the bill amends existing statutes to incorporate the new offense into Wisconsin’s violent felony and penalty provisions. Because it creates new crimes and penalties, it could trigger review by the Joint Review Committee on Criminal Penalties.

Impact

AB321 would expand Wisconsin criminal law by adding a new section, 941.293, and by cross-referencing that offense in existing penalty and violent-felony statutes. It would expose violators to Class G, H, or I felony penalties depending on the conduct, and would affect firearm owners, sellers, manufacturers, distributors, and people possessing unfinished or unserialized firearm components. The bill largely mirrors federal restrictions on undetectable firearms, but would make those acts independently punishable under state law as well.

Sentiment

The available record suggests the bill was introduced with substantial legislative support, as shown by the large bipartisan list of coauthors in both chambers. However, there is no committee transcript or recorded vote information in the provided materials, so the public debate and any formal support or opposition cannot be directly measured from the record here. The bill ultimately failed to pass pursuant to Senate Joint Resolution 1, indicating it did not complete the legislative process despite its introduction.

Contention

The main policy issue is the scope of firearm regulation, especially whether Wisconsin should criminalize possession of undetectable firearms, firearm blueprints, and unserialized frames or receivers at the state level. Supporters appear to favor aligning state law with federal restrictions and closing loopholes around ghost guns and weapons that evade security screening. Potential opponents would likely focus on Second Amendment concerns, the breadth of the possession ban, and whether the serial-number requirement and plan-possession offense could sweep too broadly, though no direct objections are included in the provided discussion record.

Companion Bills

WI SB332

Crossfiled An Act to amend 939.6195 (1) (a) 1. and 941.291 (1) (b); to create 941.293 of the statutes; Relating to: prohibition against undetectable firearms, possessing a frame or receiver of a firearm without a serial number, and providing a penalty.

Previously Filed As

WI SB332

Prohibition against undetectable firearms, possessing a frame or receiver of a firearm without a serial number, and providing a penalty.

WI LD1126

An Act Requiring Serial Numbers on Firearms and Prohibiting Undetectable Firearms

WI HB40

An Act to amend and reenact § 18.2-308.5 of the Code of Virginia and to amend the Code of Virginia by adding a section numbered 18.2-308.5:2, relating to manufacture, importation, sale, transfer, or possession of plastic firearms and unfinished frames or receivers and unserialized firearms prohibited; penalties.

WI HB1099

In firearms and other dangerous articles, providing for the offense of undetectable firearms.

WI HB1065

In firearms and other dangerous articles, further providing for definitions and providing for the offense of sale of firearm or firearm parts without serial numbers and for privately made firearms.

WI SB466

relative to the possession of a firearm without a serial number.

WI HB871

An Act to amend the Code of Virginia by adding a section numbered 18.2-308.7:1, relating to storage of firearms in a residence where a minor or person prohibited from possessing a firearm is present; penalty.

WI H545

Ban Ghost Guns & Undetectable Firearms

WI S409

Ban Ghost Guns & Undetectable Firearms

WI SB881

Plastic firearms or receivers, unserialized firearms, etc.; transfer, etc., prohibited, penalties.

Similar Bills

No similar bills found.