"he's going to walk me through the minefield of NFA paperwork"...There is no minefield, its very easy, but first make sure that short barreled rifles are allowed in your state and that your local chief law enforcement official, usually the Sheriff of your county, will sign your SBR paperwork. You need to call or stop by the Sheriff's office, and ask them if you can get Sheriff's signature for a Short Barreled Rifle application. Secretary at the front desk will know if he signs or not. If you don't have a clean legal record, don't bother asking. If Sheriff does not sign for whatever reason (he may not like machine guns, silencers, short barreled rifles, short barreled shotguns, AOWs, gun people in general), (AND you don't live in one of those "shall sign" STATES where Sheriff MUST sign as long as you have a clean legal record), then things become much more difficult.
There are some alternate law enforcement entity signatures ATF will accept on your paperwork (such as judges, but good luck with that plan). Many people have formed their own corporations that will "own" the NFA item, because they live in places where Sheriff will simply not sign. There are however questions whether these kinds of corporations will be allowed in the future; ATF is currently considering the issue. It's always best to obtain your NFA items on Form 4s, in the long run. (BTW, if you should decide to transfer it later from your corporate ownership to yourself, you will need to go through the application process again, including a $200 transfer fee for each item).
If you are buying NFA item from out of state (rather than an individual or company within your state), you will need a local FFL dealer willing to accept the NFA item for you (for a fee). That fee may be $50-200 or higher; new NFA buyers tend to be impatient and call frequently FFL, "Where is my approved Form? Where is my stuff?", thus wasting lot of FFLs time; there are also issues of storage and insurance for sometimes very expensive NFA items on FFL's premises. So find out what is the FFL's fee, so you are not unpleasantly surprised later.
Assuming that your sheriff signs and you lined up a local FFL, you will need two Form 4s (you can download them from the ATF website), fill them out (they are duplicates), each with a recent photo attached, specifying exactly what you are getting (including serial numbers), from whom, sent to whom, their FFL numbers, reason for purchase (I can provide more info on the standard verbiage, if you want), and then the necessary sign off by the sheriff (two sets of signatures, sheriff's address and phone number).
if you leave off any piece of information, ATF will not process your application, and it will set you back usually months of waiting. I read somewhere that something like 40% of forms are incorrectly or incompletely filled out, even though instructions are very simple to follow. So don't be a dummy, do it right the first time, and preferably have somebody like your FFL experienced with NFA procedures, double check your application. Some FFLs will fill out the paperwork for you, but you still have to do lot of the work, such as obtaining photos, fingerprints, Sheriff's signatures.
Some FFLs have been known to sit on your paperwork and not send it in for months, or ever, so you are always better off mailing off the complete package to ATF yourself. That way, 6 or 12 months later, you will not wondering if your long processing time is due to FFL misplacing or sending your application late, or never sending it in, or if it is just your government being very very slow.
In your package you will need to send in two sets of current (within a last year) fingerprints, on fingerprint cards that have a correct routing number for NFA branch of ATF; you can order bunch of pre-printed fingerprint cards from ATF website, at no cost.
Your police or sheriff's department can process (fingerprint) you on those cards, for a fee ($20-30).
You must include a so-called Certificate of Citizenship where you indicate that you are a USA citizen. No notary public is required, just your signature.
Plus a $200 check to ATF for the tax stamp. When they cash your check, you will know they have received your paperwork. Do not use money orders, and don't waste money on overnight mail, it will not speed things up.
You can assemble it all together in less then two hours (assuming that your sheriff signs on a spot and you have fingerprint cards ready to go, completed and filled out, FFL info, for CZ-USA and your local guy), and mail it to the CORRECT current ATF address.
Then wait 6 to 12 months for your government to "efficiently" process it (if you are lucky), longer if not lucky. FBI will check your fingerprints against their records, which apparently takes several months, ATF will also check with the local FBI agency re: your background.
After your FFL received the approved paper (it will be one of the two Form 4s you sent in, now with a $200 tax stamp attached), at that point you can buy and attach your Evo stock, making it SBR.
Be aware that some "out of state" purchases require two sequential transfers, meaning two sets of applications and two $200 stamps; first transfer is to your dealer in your state, the second transfer from your dealer to you. This usually happens when you are buying NFA item from an out of state individual. Transfers happen sequentially, so expect double the time listed above.
Out of state FFL may also have e.g. machine gun in stock on Form 3 (as opposed to Form 4), which then becomes a tax free dealer-to-dealer transfer, and you only pay the $200 transfer from your dealer to yourself.
