UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported)

September 16, 2026

STURM, RUGER & COMPANY, INC.

(Exact Name of Registrant as Specified in its Charter)

(203) 259-7843

Registrant’s telephone number, including area code

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 1.01 Entry Into a Material Definitive Agreement.

On September 16, 2026, Sturm Ruger & Company, Inc. (the “Company”) and Computershare Trust Company, N.A., as rights agent (the “Rights Agent”), entered into an amendment (the “Amendment”) to that certain Rights Agreement, dated as of October 14, 2025, between the Company and the Rights Agent (the “Rights Agreement”).

The Amendment accelerates the Final Expiration Date of the Company’s common share purchase rights (the “Rights”) under the Rights Agreement from the Close of Business (as such terms are defined in the Rights Agreement) on October 13, 2026 to the Close of Business on September 16, 2026, and the Rights Agreement will terminate at such time. At the time of the termination of the Rights Agreement, all of the Rights distributed to holders of the Company’s common stock pursuant to the Rights Agreement will expire.

The foregoing description of the Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the Amendment, which is attached as Exhibit 4.1 hereto and incorporated herein by reference.

Item 1.02 Termination of a Material Definitive Agreement.

The information set forth above under Item 1.01 is hereby incorporated by reference into this Item 1.02.

Item 3.03 Material Modification to Rights of Security Holders.

The information set forth above under Item 1.01 is hereby incorporated by reference into this Item 3.03.

Item 7.01 Regulation FD Disclosure.

On September 16, 2026, the Company issued a press release announcing the Amendment. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated into this Item 7.01 by reference. The information in this Item 7.01, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as expressly set forth by specific reference in such filing.

ITEM 9.01 Financial Statements and Exhibits.

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized.

Dated: September 16, 2026