Tightness of the barrel has nothing to do with the ability of the chamber to contain the pressure. All Benchrest rifles, including the 1000 yard guns in the big Weatherby wildcats have the barrels installed "snuggly". Not supertight like the factories do.
Any big caliber benchrest rifle can have the barrel removed with a simple aluminum barrel vise and an inserted action wrench. And when they change barrels at a match, they simply thread on the new barrel and "snap" it to tight.
Look at how a Savage barrel is installed. It uses a barrel nut and there is no tightening of the action on the barrel at all..........and once again, available in real "boomer" chamberings.
Gunsmiths have been trying to figure out for years why Remington and other factories install their barrels so darn tight. No reason for it as we can tell.
Tightness of the barrel might not have an effect on the barrel's ability to hold pressure, but it can have an effect on headspace.
There have been quite a few takedown rifles manufactured along the lines of the link I provided and your thread. I cannot speak to all of them, but those that I am familiar with provide a means of adjusting and compensating for wear and/or looseness in the threads. The link and your modification do not.
I have no control over what someone might do in modifying his firearm, but I do recommend that anyone contemplating such a modification should do his own research into the forces involved and the potential for damage or injury before proceeding.