AlexanderA said:
The main reason for buying a "paperweight" or "80%" receiver is paranoia. Otherwise, the economics don't make sense.
Not just paranoia (which is not unfounded in some states, as bans have been enacted or increased what can create a prohibited person well beyond federal law that result in confiscation at the individual level.)
I have used them to have a CA legal AR pistol.
Under CA law most semi auto pistols need to be on the special roster to be imported or manufactured.
Buying a complete lower as a handgun in California is generally not an option, they are firearms but they are not on the registry and don't have the features required to be on the registry so cannot be sold as a handgun.
Commercial stripped lowers are as a result only useable as long guns.
This means you must purchase/transfer an already completed firearm in pistol configuration manufactured as a pistol specifically for the CA market, or manufacture your own.
While commercial ones have to be set up for CA law, which requires they be in single shot mode to sell, and that they have a fixed magazine, these reduce how many are available in CA, and reduce price competition so most are overpriced.
Additionally most will be in .223, which performs a lot worse than some other options from a short barrel. So you have to pay for a .223/5.56 upper that is then relatively worthless and buy a seperate upper to replace it with a more appropriate caliber. While if you made it yourself you wouldn't have to get the .223/5.56 upper at all (which if you are not going to use as a pistol is then only good for a SBR which is not even an option in CA.)
Making it yourself it still needs to meet the single shot exemption, so when you first make it you will need to make it single shot (it can be changed afterwards.)
It also cannot have a removeable magazine outside the pistol grip and be semi-auto, so it has to have what qualifies as a fixed magazine under the law and requires a tool to remove.
Since it will be a single shot at first, it needs to be built with both of those considerations in mind initially, then if it later is converted to a multiple shot semi auto it still needs to be a 'fixed' magazine under the law and require a 'tool' to remove the magazine but no longer needs to remain single shot.
So it is still not just as simple as making your own, but making your own is step one to legally owning such a pistol in CA.
An additional reason:
I also like to start all my AR type firearms as a pistol since 2011 when the ATF determined you can turn a pistol into a legal rifle (16" barrel 26" min overall length) and back into a pistol. You can never turn what starts out as
rifle into a pistol however. So you can benefit greatly by starting all of your ARs as pistols irregardless of what you want them to be. This gives you long term flexibility.
Now CA law on going from pistol to rifle and back is less clear, so I don't do so. However if I find myself out of state I retain more freedom with such guns to modify them as I wish due to taking the extra steps to make a pistol instead of a rifle initially.
So it simply makes sense to make all your ARs pistols to start, and making them a rifle initially is just tying your hands for no reason.
So in CA at least there is several reasons beyond other places for making your own.
