The main purpose of this legislation is to prevent the United States Postal Service from moving forward with a proposed rule that would regulate the mailing of firearms, specifically pistols and revolvers that can be concealed. The objective is to ensure that these firearms cannot be sent through the mail, which supporters believe could help reduce the risk of illegal firearms distribution. The key provision of the legislation is a clear prohibition against the Postal Service finalizing, implementing, or enforcing the proposed rule concerning the mailing of concealable firearms.