8.3.3 Lightweight sport rifle. All rifles chambered for ammunition as in Rule 126.96.36.199 and air or CO2 rifles of calibre 5.6 mm (.22 in) or less are permitted, subject to: 188.8.131.52 The overall weight, including sights and all other accessories, shall not exceed 4.5 kg; 184.108.40.206 There is no minimum trigger weight restriction but it is the responsibility of the shooter to make sure that it is safe. The RCO has the authority to rule that a trigger is unsafe if he believes it to be so; 220.127.116.11 When used with a magazine, the rifle shall not be loaded with more than 10 cartridges or projectiles, even though the magazine may be of a larger capacity; 18.104.22.168 The stock may be adjustable for length; 22.214.171.124 The cheekpiece may be adjustable; 126.96.36.199 The forend – adjustments and additions are permissible up to 150mm from bore centre within the profile of the stock. Simple shaping to aid grip is permissible but this must not be anatomical, i.e. they must not be shaped to closely conform to the contours of the hand; 188.8.131.52 The curvature of any butt plate is such that at maximum depth (from a line drawn between the toe and heel of the plate) is not greater than 20mm. No butt hooks are permitted; 184.108.40.206 The butt plate may be adjustable vertically in either direction without rotation; 220.127.116.11 Slings are not permitted in any position.