What is a plunger button
A Plunger Button is a fine tuning device with an adjustable spring cushioned tip inside a housing. The plunger button is installed on the riser with the tip protruding above the arrow rest and its purpose is to push the arrow to the left, on a right hand bow, to compensate for archer's paradox. The side of the arrow is in contact with the plunger button tip when the arrow is sitting on the arrow rest.
The spring is tuned to allow a certain amount of movement of the arrow towards the riser on release of the arrow, bringing the arrow to the ideal "centre shot" location. The plunger button is used to compensate for the arrow's flex, since the arrow flexes as the string pushes onto it with a very high acceleration, creating what is known as the archer's paradox.
A recurve must have a threaded hole or sleeve in the riser to accept a plunger button.
The arrow rest needs to be positioned so that the centre of the arrow and the centre line of the pressure button line up.
Fine or micro tuning of the plunger button is arguably one of the most critical steps when tuning the recurve.
The tip of the plunger is susceptible to extensive wear and to prevent tips wearing out, some tips are made of durable materials like Teflon. Invariably new archers cannot justify spending a lot on a plunger and opt for the entry level model, which is at the right price but its tip wears quickly and replacement tips are not available, so a new plunger must be purchased.
Similarly, the spring on an entry level plunger will be rough or not press in smoothly as it is built to a price with cheaper springs that do not hold up over time. Better quality buttons are much easier to adjust as the springs are made of far superior quality and can take the stress of micro adjusting and they never relinquish their tension.
Once the plunger is fine tuned, rarely would the button need to be re-adjusted. A high quality plunger button is an excellent investment as it will last a lifetime.
Greater accuracy comes with quality buttons. It is claimed 4 out of 5 Olympians use a Beiter plunger button.
The plunger is also known as a pressure button or Berger button, invented by tournament shooter Norman Pint, but named after well known archer Victor Berger.