In Union Metallic Cartridge Company v. United States Cartridge Company, the Supreme Court was asked to decide whether the United States Cartridge Company had infringed upon the patent of the Union Metallic Cartridge Company. The Union Metallic Cartridge Company had patented a method of manufacturing cartridges, and the United States Cartridge Company had been using a similar method. The Supreme Court held that the United States Cartridge Company had infringed upon the patent of the Union Metallic Cartridge Company. The Court found that the United States Cartridge Company had copied the patented method of the Union Metallic Cartridge Company, and that the patent was valid. The Court also held that the United States Cartridge Company had not acted in good faith, and that the Union Metallic Cartridge Company was entitled to damages. The Court's decision established that patent infringement is a serious matter, and that companies must take care to ensure that they are not infringing upon the patents of others. The decision also established that patent holders are entitled to damages when their patents are infringed upon.

In Union Metallic Cartridge Company v. United States Cartridge Company, the Supreme Court was tasked with deciding whether USCC had infringed upon UMC's patent for a metallic cartridge case and primer cup combination. The majority opinion found that USCC did indeed infringe on UMC's patent, but Justice Field dissented from this decision. He argued that although the two cartridges were similar in design, they were not identical and thus could not be considered an infringement of the original patent held by UMC. Furthermore, he asserted that even if there had been some similarities between the two designs, it would have been impossible to prove beyond reasonable doubt that these similarities constituted an infringement of any kind due to lack of evidence or testimony regarding how exactly each company arrived at their respective designs. As such, Justice Field concluded his dissent by arguing against finding USCC guilty of infringing on UMC’s patent rights as no clear proof existed to support such a claim.