The fact that the Helice system uses the bolting principle of artillery pieces, that it requires only 4 parts, and that it's extremely strong (powder and shot charges listed) are the primary characteristics listed on p. 7 of the 1922 V-C catalog. It does refer to "progressive tightening", although as Miller explained, many doubles have that feature to compensate for wear. On p. 9 of the same catalog, there is reference to tightening if there's any play (which V-C explains as "very rare"). But they certainly don't tout the adjustability of the action in the same way as, say, Lefever did on his guns.