Read that a few months ago and made some slings to try the concept, a few things to mention:
1- You need to make sure your sling swivels and stock can withstand the tension exerted by this style of sling.
2- The 'proper' M1907 sling is a bloody heavy contraption that isn't really fit for purpose on a hunting rifle.
3- The alternatives are OK (he came up with a design that was a good compromise) but the length of the sling will always be critical, and for overall stability you can't beat a bipod.
Better to have an adjustable sling for carrying the rifle in relative comfort/ease, but good to know some of these techniques.
A few people I know (then myself) have gone for the TAB gear slings with flush cup mounts in the stock on the opposite side of bolt; they are good if you can get them but a little heavy.
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