I came across this NRA article by Jeff Cooper about the Old British 2 point attachment system:

https://www.americanrifleman.org/articles/2014/10/16/the-only-way-to-sling/

I have no interest in the scout rifle concept, so ignore that, but the sling attachment and use of it was interesting. I have a couple of questions

Does anyone have experience with this sling method? and,

Please explain this: "on which a conventional QD stud had been fitted as an extension of the forward floorplate screw?" Does anyone make a quick detach stud ended front action screw?

"He showed me his Mannlicher SSG, on which a conventional QD stud had been fitted as an extension of the forward floorplate screw."

edited and updated.

Have an answer?

You don't need a special screw/QD stud attachment to the floor plate. Just put the mounting system(QD stud, Pachmyer etc.) ahead of the floor plate in the stock. Works fine. I have several rifles with either a Ching sling(3 point set up) and what Cooper referred to as the CW sling(basically same as above) and either one works very well for shooting and is very fast to get into with a little practice. The 3 pt. Ching sling is more practical for both shooting and carrying.

The Pachmayr flush mount is what I use http://www.midwayusa.com/product/662393/pachmayr-flush-mount-sling-swivel-blue-package-of-2
But there are other brands as well, if you want a sling that can be detached quickly.

I figured thats what most would do. He even mentions the Pachmayr flush mounts in the article. I'll never claim my eyes are the best, but if you look at the far right pic up close it sure looks like that sling is coming from the front action screw/area?

I am assuming that he just welded a sling stud head to the floorplate screw.

Or else found a machine screw stud that was the right length and thread pitch to be used as the floorplate screw.

But since it says he "modified" it, I would assume he did the weld.