Wow didn't realize so many of you guys on the forums are from countries with such strict gun control. Even fallschirmjager has to go through red tape to get "parts" for his rifle! Not talking parts that would alter the actual internals of it, we're talking a simple scope mount or iron sights?
Suppressor though, even in states where it's legal, is still a hassle to get a hold of. Same process as getting full automatic weapons, bottom line is it involves the ATF.
Though it makes you wonder if America would actually be better off with all the firearms we have in the case of a zombie apocalypse. Only benefit I can think of is killing as many of the infected we come across to reduce the spread. Easier to do if the civilian population can help with that process rather than rely on what national guard units are still in country(since a lot of our military is deployed...).