The knurled nut for swivel tension.
Yeah. I've heard that the friction tensioning knob is hard to adjust with your fingers and you need to get the pliers on to it.
However, I've found an awesome U.S aftermarket product called the 'Pod-Loc' to fix this problem.
The Pod-Loc is a tension Lever that replaces the friction tensioning knob to give you much better control and leverage. It suits all Seires S (Swivel) Harris Bipods.
I've read lots of user reviews and all have them have been praising this aftermarket device saying it makes the swivel bipod SO much more easier to use. It also tucks away when not in use so it wont catch on anything whilst your carrying your rifle.
Problem is, I can't for THE LIFE OF ME find anyone in the U.S willing to ship it over here.
For more information, just Google it.
Here's some pictures.