Ruling 2011-4 Pistol-to-Rifle question

[Diamondback]

I've been penciling out a "convertible" Ruger .22 Charger build idea that can switch-hit between pistol and rifle like a T/C Contender or AR pistol, and as I read Ruling 2011-4 it provokes some questions.

In United States v. Thompson/Center Arms Company, 504 U.S. 505 (1992), the United
States Supreme Court examined whether a short-barreled rifle was “made” under the NFA
when a carbine-conversion kit consisting of a single-shot “Contender” pistol was designed
so that its handle and barrel could be removed from its receiver, and was packaged with a
21-inch barrel, a rifle stock, and a wooden fore-end. The Court held that, where
aggregated parts could convert a pistol into either a regulated short-barreled rifle, or an
unregulated rifle with a barrel of 16 inches or more in length, the NFA was ambiguous and
applied the “rule of lenity” (i.e., ambiguities in criminal statutes should be resolved in
favor of the defendant) so that the pistol and carbine kit, when packaged together, were not
considered a “short-barreled rifle” for purposes of the NFA.

https://www.atf.gov/firearms/docs/ru...stols/download

The basic concept is a "kit gun" with a common core receiver/FCG/chassis assembly, a 1913-mount tube to slide on either brace or stock, and interchangeable rifle and pistol barrel/forend assemblies. (This doesn't have any fancy "tactical" purpose, the concept is more a combination of "2 plinkers in one," "the GF and I could slap his-and-hers together with hand tools as a relationship-building activity" and "climbing the mountain just because it's there and to see what's on the other side.")

This is the chassis I was looking at for the core of the build: https://www.midwestindustriesinc.com...i-1022-tdc.htm The idea was to screw in a 1913 brace-mount where it's intended to take a stock, but then since a stock Charger is 19" OAL and I need a 26" length with stock folded in rifle config that means I need at least a 17" barrel. (26" min OAL - 19" Charger w/10" barrel OAL = 7" added length requirement, 16" barrel only adds 6") IF I'm interpreting this right (and that's a BIG "if"), as long as I do my build as a Charger pistol first rather than a 10/22 rifle, and make sure that the rifle option is over 26" OAL with stock folded, I should be good to go... then again ATF is notorious for never wanting to let anything be easy or straightforward.

I know ATF doesn't like to do Determination Letters without being able to soak you for the cost of building a sample and taking the risk, so my question to any SBR/AOW specialists we have is... well, two.
1. Does this sound like a Title I to you if you were building it, or if this came into your shop as a factory Ruger package, would you be comfortable selling it as a Title I?
2. If I need to have an attorney contact ATF for a DL, any suggestions about good guys who might be affordable to a casual hobbyist-gunsmith? I know John Pierce has a solid reputation as a firearms-tech law specialist, but I'd like to hear some reviews before I pick someone to reach out to if needed.

[Screwball]

Put the 16” barrel on… then the stock. OAL of a rifle (which that would be at that time) is measured with the stock unfolded.

You should be over 26”.