C’mon fellas - folks build this kinda of thing every day, and have for many years. If you aren’t familiar with the ACTUAL LAWS surrounding NFA items, you’re not doing anyone any favors by spouting mistruths as if they were gospel, just because it sounds good on the Internet.
In the US, a probable federal felony.
This keeps getting kicked around in this thread, while there is absolutely no reason to suspect such to be true. “Probable” felony, is nothing more than speculation. The work done in that “Weapon made from a rifle” (‘cuz it isn’t a pistol on paper) looks to have been done by a highly skilled smith and stockmaker, and there’s no reason to expect such a skilled and knowledgeable maker would be totally ignorant of the laws by which he lives.
It might not be your particular taste, but there’s no reason to accuse the maker of anything nefarious.
If located in the US, it's either an SBR, or an unregistered SBR; it can't be a pistol (unless the receiver was cut, and then rewelded as a new pistol).
More bad assumptions and assertions here. It’s not an SBR because it is no longer a rifle. The NFA classification for this type of weapon is “Weapon made from a rifle.” The “remanufacture” Avenue you suggest, where a receiver were cut (destroyed) then rewelded and reserialized by a Type 7 is convoluted.
Page 4 of ATF Form 1, application to make a firearm offers definitions for these firearm types.
$200 for a Form 1, a 7 month wait, a custom stockmaker and a decent gunsmith, almost any of us can have that WMfaR LEGALLY in the US.
Also - recoil in specialty pistols really isn’t bad, AND the steep grip angle is intentional to help manage recoil and control the pistol during such. It keeps the pistol in your hand, rather than pushing a sloped grip through your hand. Most folks aren’t familiar with bolt action Specialty Pistols and assume the recoil is terrible, but in reality, you can pack a LOT of cartridge into a small package and never feel as much hand pain as even a 357mag J frame.