The Parker Hale moderators use a 1/2" x 20 UNF thread.
In my experience, they don't affect accuracy but do affect the point of impact. They are very effective, and simple to maintain.
Our Pommie contributors can correct me if I'm wrong, but I believe that these aren't being made anymore as Parker Hale closed down (went bust, whatever).
The last one I bought was made by somebody else with a "made under licence for PH" note on the box.
In my experience, they don't affect accuracy but do affect the point of impact. They are very effective, and simple to maintain.
Our Pommie contributors can correct me if I'm wrong, but I believe that these aren't being made anymore as Parker Hale closed down (went bust, whatever).
The last one I bought was made by somebody else with a "made under licence for PH" note on the box.
