I've got a few random questions that have been piling up.
1- What's the story on .50 caliber ammunition being restricted? I've heard that it can't be manufactured for civilians so the only market is what comes in from military surplus. I've also heard that too has been made illegal so 50 ammo will one day dry up once the current supply on the market is all purchased. Is this a myth?
MYTH
2- I'm aware you can have a .50 upper mailed to you, but if purchasing a complete .50 caliber rifle do you really have to write a letter to the chief of police to inform them of your purchase? Are there any additional hoops you have to jump through that you don't with a standard rifle? If so, do you have to do the same with the assembled .50 if you bought an upper and built your own?
No need to inform anyone. Just like any other rifle.
3- Are 5.7mm armor piercing rounds "legally" restricted from civilian use, as in it's against the law to use, or is this a business policy and they just don't sell it to civilians? According to the chart at the bottom,
http://en.wikipedia.org/wiki/5.7x28mm some bullets are class 3. I've never heard of ammunition being class 3 unless it was explosive.
Imported Armor piercing ammunition can not be purchased directly, there are a few ways around it to get some 5.7 but expect to pay WAY to much money
4- I'd like to replace the bolt carrier in my WASR-10 with a stainless steel one, just for appearance sake. Full auto bolt/carrier packages are about the same price as semi auto ones and they're more likely to be in stock. I know the only difference is the extra metal at the back of a semi auto carrier to prevent a hard hammer strike if the second hook fails and the open slot for the auto sear on a full auto one, so just having "full auto" parts won't make the rifle FA. Are there any legal issues with using FA parts in a SA rifle so long as you're not converting it?
Just replace it, you are changing nothing as long as you arn't changing the import part ratio.
5- What's this "10 parts" rule I've heard from time to time about American made parts on a rifle and not being able to buy imports without them? I'd like to build an AR-15 at some point and I don't want to be in legal hot water because 9 parts are US made and 1 was made elsewhere.
Go here and read this information, it's a relatively simple break down of 922r compliance which is what you are questioning.
http://home.comcast.net/~navy87guy/home/922r.html
6- Master key part 2, my first post here was asking if it was legal to mount an 18" barreled shotgun without a stock under a rifle. My new question is, if you register an SBS and mount that in the same fashion, is the rifle as a whole now an NFA that has to be registered again as a single unit or will the original SBS registration be enough? To put it a little more simply, if you bought a grenade launcher, you wouldn't have to register the rifle you put it on right?
No the rifle is still a rifle with a SBS mounted out front, no change to Title II status. No need to register a title I rifle just because you put a title II 40mm launcher out front either.