Cheers for that 1000, I had assumed that was what he meant, but we all know what happens when one assumes, eh ?
It is a carry sling rather than a shooting aid, and although most of this type can be hastily adapted as a support, they are nowhere near as effective as a properly mounted shooting sling. The SA80 is an example of those which cannot.
Bbl mounted slings, (or bipods,) have an inclination to move the POI due to flexing the bbl, however that on the FAL and SLR are fairly sturdy and it doesn’t have too much effect on man sized tgts at normal battle ranges.
When shooting at longer ranges or on smaller tgts I personally would be inclined to use a different means of sp.
The wpn in the pic is the std Argentine FAL, they also fielded the FAL PARA and the heavy bbl version, (which looks quite different,) known locally as the FAP.
The Aussies and Canucks also used the light support version - the L2A1 and C2 respectively.
The handguards on the pictured FAL are relieved for a bipod, (as used on the Austrian StG58,) but as far as I know it was never issued with one.