That's exactly what everyone over here was thinking. And we are positive that Heller protects shotguns under the common usage doctrine.
Here's the problem: The act exempts standard pump action shotguns from the assault weapons category, but not from the large capacity ammunition feeding device category. The Remington 870, and like guns, hold 7 rounds, right? Yes, when measured with 3" shells. But shell length is not uniform! How many 1 3/4" shells can the 7 shot Remington 870 hold? Answer: At least 12. Ergo, by the letter of the law, the 870 with its integral magazine that cannot be irreversibly modified is a large capacity ammunition feeding device, the possession of which will soon be a misdemeanor offense. Think about it. If the world's most popular shotgun is protected by Heller, then the amendments to Penal Law 265 are overbroad.
Of course, this was another charge raised in the suit. Petitioners and sellers have a legitimate fear of prosecution if they want to exercise their right to buy or sell an 870, post-SAFE Act. Scary, isn't it?