Writing about lawsuits involving guns could be a full-time gig here at TFB. Unlike the recent raft of lawsuits challenging various gun control measures, we have a good old-fashioned patent suit today. The parties are names you probably already know, Palmetto State Armory and Shield Arms.

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As a disclaimer, nothing in the article is legal advice. While I am a licensed attorney, I am not a patent attorney. This is a news article for educational and entertainment purposes. Don’t base any of your decisions around intellectual property on my analysis.

What Started This?

Shield Arms is best known for its S15 magazines, which add five rounds of capacity to the Glock 43X and 48. Shield Arms fit all those extra rounds into the same space by using a metal magazine body rather than the polymer-over-metal design of the factory magazines.

The PSA Dagger series of striker-fired pistols is compatible with Glock parts, including magazines. Recently, they introduced the Dagger Micro, which is compatible with G43X/48 parts. Rather than use the 10-round Glock factory magazine or the Shield Arms S15, PSA created their own 15-round magazine.

However, Shield Arms had previously patented their magazine design. United States Patent 11,747,102 “Increased Capacity Ammunition Magazine” covers the steel magazine design. Counsel for Shield Arms sent a letter to PSA regarding the potential patent violation. The letter told PSA to “immediately cease and desist any further manufacture, sale, or offer to sell” Dagger Micro magazines. It also threatened that if PSA continued to sell those magazines, it would constitute willful infringement of the Shield Arms patent, and would expose PSA to liability including treble damages and attorney’s fees.

This kind of letter is a not uncommon thing in the world of law. Cease and desist letters happen all the time. There are only a few things that you can do when you receive a cease and desist. You can do what it says, you can send a response stating your position, you can ignore it to see what happens, or you can get the party started and file your own lawsuit first. PSA took the last option on that list.

The Lawsuit

With the demand letter in hand, PSA responded by filing the lawsuit. It is Case No.3:23-cv-05890 in the United States District Court for the District of South Carolina for anyone interested in keeping tabs. PSA is based in South Carolina, hence filing the lawsuit there.

The main thrust of PSA’s lawsuit is that the Dagger Micro magazine (somewhat funnily referred to as the “Accused Magazine” in the court papers) does not violate the Shield Arms patent. The Shield Arms patent refers to a “tubular metal magazine” with a “spacer” extending from the forward wall of the magazine. The Dagger Micro mag uses a different construction, with a polymer spacer attached to the front of the metal body.

The Shield Arms patent also describes the interaction between the metal body of the magazine interacting with the polymer magazine catch of the pistol. PSA uses a different construction. The polymer spacer interacts with the magazine catch, not the metal portion of the magazine body.

Lawsuit Alert: Palmetto State Arms v. Shield Arms

PSA draws several other distinctions with the Shield Arms patent like the floorplate being constructed of polymer rather than metal. The patent is 19 pages so there are probably areas of similarity that Shield Arms will highlight in its response. One area Shield Arms is likely to hone in on is that the sidewalls and rear face of the magazine are constructed of metal rather than the “polymer or polymer-over-metal” designs that predate the S15.

Lawsuit Alert: Palmetto State Arms v. Shield Arms

What is PSA Asking The Court To Do?

An initial complaint, the document that begins a lawsuit, always ends with a statement of the “relief requested.” These are the things the plaintiff(s) want the court to do to resolve the issue. Palmetto State Armory is primarily asking for “declaratory relief,” which in this case is a statement from the court that the Dagger Micro magazine does not violate the Shield Arms patent. PSA also seeks to prevent Shield Arms from stating that PSA is violating the patent in question, as well as their attorney fees and costs for bringing the lawsuit. It is a fairly standard thing to request attorney’s fees in a lawsuit, but courts only grant attorney fees in patent suits in “exceptional cases.” 35 USC § 285.

The Response

Shield Arms responded with a public statement. That statement included a passage described as part of a letter sent by PSA’s attorney. It reads:

PSA understands that this litigation will likely be very time-consuming and costly for Shield Arms and that Shield Arms may now realize that it was overly zealous in asserting its purported patent rights against the Accused Magazine. PSA also recognizes that Shield Arms, has, historically, been a good business partner for PSA. Thus, while confident it will be successful, PSA is open to a quicker, cheaper alternative that may help salvage the parties’ relationship moving forward.

Shield Arms also said in its statement that it intends to “protect [its intellectual property] to the fullest extent possible.”


If this case is destined to remain in litigation, this is the very beginning. It is also possible that the parties find a way to settle before this suit progresses. We will all have to keep an eye on the docket to see where this one goes. I honestly have no idea if the differences highlighted in PSA’s lawsuit will be enough to carry the day, or if the court will be more persuaded by the metal construction of the magazine. We will have to keep an eye on this one to see what happens.

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