Yes, cranky, if you hunt up an exploded diagram of them, you can work out how the action worked.
Basically, the populux outer shell was just that, a shell.
It contained a tube that the barrel and bolt slid into and functioned in.
Part of the issues that plague the design is that a tube sliding inside a tube inherently has a lot of friction points "built in", despite the reduction of the contact points to the barest minimum.
To overcome that friction and still do all the other mechanical functions required, such as cocking the hammer, etc, required relatively high powered ammo.
The few times that I got mine to run a full magazine without problems was with "Stingers", that stuff was pricey, even then.
What shooters of the original versions used for ammo, I have no idea.
Then there were also issues with dirt/debris management.
If you look at the diagram, you can see that the only place the powder residue can escape from the action is through the ejection port and through any of the small holes/slots cut into the outer tube.
It did not take all that many rounds through the pistol to turn whatever lube you used into a brown/black sludge that further retarded the action.
On top of that, it is abrasive and caused accelerated wear on many of the small parts exposed to it.
Being a blowback action, the gas pressure in the ejection port area caused that debris to spread throughout the action.
On the Olympic clone of the design the major components were made of stainless, yes, it didn't rust but stainless is inherently softer than traditional gun steel so the bolt and tube soon wore down and introduced unwanted slop into the action, thereby inducing more friction.
I do not know what type of steel was used for these parts in the original design, hopefully, someone will chime in.
At the end of the day there was just so much "built in" friction that the action just could not function with out premium ammo and, even then, it was kinda sketchy.
Anyhow, that is my forensic determination after studying the thing for a few years.
YMMV