Dear Vince, I don’t know where you got your Misconceptions from, but they are way out…
First, the Colt" Potato digger" was so named because it operated on a swinging link, which used the jet of gas from a barrel vent to force a cup on an arm, downwards, and this was linked to a action bar, which drove the bolt backwards ( a bit like Cocking an air rifle.)
The swing of the gas cup was quite wide, and if the gun was not elevated properly on its tripod, would dig into the ground…hence “Potato Digger”.
Secondly, whilst the Colt M1895 and its WW I version, the M1914, were sold to Allies in various calibres, they did not “Shoot Low”—hence no relationship of bullets “digging Potatoes”
Thirdly, WW I Colts were in Canvas Belt use ( .30/06, .303Br, 7,62 Russian, 6,5 Italian), all cartridges with .448 or greater head diameters…those links shown at the most were .400 (more like .380) diameter…forcing them onto a .450 diameter shell would splay them out so much to be useless.
Lastly, the 6mm Lee Navy, although of a .448 head diameter( equivalent to 6,5 Italian Head size) was effectively obsoleted by 1905, and existing 6mm Guns in USN service were either converted to 30/40 Krag or .30/06, if at all. It is assumed that the USN guns were used during the Philippines Moro Insurrection, where 30/40 Krag was the common calibre of US Forces. More detail is needed on Naval Use of the Lee calibre.
Now, why do these links have to be “push through” Links???..their format makes them ideal “pull back” links, and as for a Miniature MG, you obviously have not seen the miniaturisation of the Maxim 7,63x25 Mauser gun, for many years in the Foyer of Bapty’s Film Guns, in London. Granted, the 7,63 Mauser is high powered, and has a stiff recoil, but a so called “low power” .38 cartridge ( say the .38 Long suitably Loaded with smokeless), could be made to operate a suitably sprung action on the Maxim or even straight blowback principle.