Any type of Compressed Air or CO2 (NRA Rule)
1. Caliber: 4.5 mm (.177 caliber).
2. The weight of the rifle (including air or CO2 tank, if appropriate, but not including the sling) with sights may not exceed 7.5 lbs. (3.40kg). Weights may be added in accordance with rule 3.2 (h) so long as the total weight does not exceed 7.5 lbs.
NOTE: If a rifle rest/bipod is used, it must be removed for shooting and should be used only for support of the rifle during position change.
3. A set trigger is prohibited. A minimum trigger weight of 1.5 lbs is recommended.
4. The butt plate may be adjustable but may not be adjusted during the competition (must remain fixed in place for all positions).
5. Thumb hole, thumb rest, palm rest, heel rest, hooked butt plate and spirit level are prohibited.
6. Sights: see Rule 3.7.1.
7. The length of the stock and the height of the cheek piece may not be changed during the course of fire.
8. Barrel weights are permitted provided the overall weight of the rifle does not exceed the maximum limitation and are within a radius of 1.18 inches (30mm) from the center of the barrel. Other weights are allowed as long as they stay within the confines of the original stock and cannot be changed during a competition.
9. Internal Modifications - Only factory manufactured part’s designed for the specific model gun being fired may be used. Parts in the gun may not be removed and all parts must be in their correct positions and functioning in their designed manner. Internal parts may be honed or polished to improve their internal function, but such improvements may not alter their intended function. Compensators or muzzle brakes are prohibited.
10. External Modifications - A single layer of tape or non-glare paint may be placed on the barrel for the purpose of reducing glare.
11. Stocks - The right & left sides of the stock must be mirror images of each other. Factory installed stocks may be altered in length. The butt of the stock may be rough, checkered or scored to provide a non-slip surface.