A. TRAP MACHINE
A trap machine, which throws targets at an unknown angle, shall be used. All trap machines used to throw ATA registered targets shall be so manufactured, modified, or equipped as to interrupt irregularly the oscillation of the trap or otherwise assure the unpredictability of the flight of substantially all targets thrown.
Each gun club that throws ATA registered targets must have on file in the ATA main offices a signed Affidavit that the trap machines used to throw registered targets meet the requirements of this rule. The State/Provincial ATA Delegate is responsible for the enforcement of this Rule.
B. TRAPHOUSES
Traphouses must adequately protect the trap loaders and shall not be higher than necessary for that purpose. It is recommended that traphouses conform to the following specifications:
1. Length not less than 7 feet, 6 inches, nor more than 9 feet, 6 inches.
2. Width not less than 7 feet, 6 inches, nor more than 9 feet, 6 inches.
3. Height not less than 2 feet, 2 inches, nor more than 3 feet, 0 inches, the height to be measured from the plane of the number 3 shooting position.
It is recommended that the throwing surface (throwing arm or plate) of the trap machine be on the same level as that of Post 3 and the target height setting pad.
C. POSTS
The posts shall be 3 yards apart on the circumference of a circle whose radius is 16 yards. Handicap posts, when used, shall be prolongations of the lines shown in the Diagram below, commonly known as fan shaped. The distance between posts at 16-yards (14.6m) shall then be 3 yards.
D. TARGETS
No target shall measure more than four and five-sixteenths (4 5/16, 4.300) inches in diameter, and not more than one and one-eighth (11/8, 1.125) inches in height and with an allowable variation of not more than five (5) percent from these specifications. A target shall not weigh less than 95 grams or more than 105 grams with a variation of not more than plus or minus 5 grams per Target Lot. A Target Lot is defined as all targets with the same production lot number.
E. FLIGHTS AND ANGLES
Singles targets shall be thrown not less than 49 yards nor more than 51 yards. Distance measurements are on level ground in still air. Targets shall be between 8 feet and 10 feet high, when 10 yards from Point B. The recommended height is 9 feet. The height at a point 10 yards from Point B is to be understood to mean height above an imaginary horizontal straight line drawn through the post and Point B. (See Diagram)
Target height may also be set based on the height of the target at ten yards as measured above the level of the trap arm in the house rather than the height as measured from the number 3 shooting station. This is the recommended procedure at facilities where the installation of traps in the houses is inconsistent as to height.
Point B is defined as the intersection of a line measured 1 foot 6 inches or 2 feet 6 inches from the outside vertical wall (farthest from the shooting stations) of the trap house and the centerline of the trap house.
Clubs constructing new trap houses and fields should use the same point B measurement as their existing fields to keep all fields as consistent as possible.
In Singles shooting the trap shall be so adjusted that within the normal distribution of angles as thrown by the trap, the right angle shall not be less than 17 degrees measured to the right of center (3BF), and not less than 17 degrees measured to the left of center (3BF), with a total angle between outside target limits of not less than 34 degrees. (See Diagram, below) Under no circumstances shall a Standard Model 1524 trap be set in less than the #2 hole. Any other trap machine shall be adjusted so as to throw not less than equivalent angles. Where terrain allows, a visible stake must be placed on the centerline of the trap on the arc of a circle that has a radius of 50 yards and its center is Point B (Point F, Diagram).
To help in determining legal angles, stakes may be placed on the arc of a circle that has a radius of 50 yards and its center is Point B. One stake should be placed where a line drawn through Point A and Point B intersects this arc and another stake placed where a line drawn through Point C and Point B intersects the arc. These lines and stakes will assist in determining the required angles, but it is to be understood that the angle specifications apply when the target is from 15 yards to 20 yards from the trap rather than where the target strikes the ground. However, no target is to be declared illegal unless it is significantly outside normal parameters (e.g., more than 10 degrees outside normal).
In doubles shooting, targets shall be thrown not less than 44 yards nor more than 51 yards. Distance measurements are on level ground in still air. Targets shall be between 8 feet and 12 feet high, when 10 yards from Point B. The recommended height is 9 feet. The height at a point 10 yards from Point B is to be understood to mean height above an imaginary horizontal straight line drawn through the post and Point B. (See Diagram II). The trap shall be adjusted so the angle of target spread is not less than 34 degrees. Target height may also be set based on the height of the target at ten yards as measured above the level of the trap arm in the house rather than the height as measured from the number 3 shooting station.
The maximum right angle will appear to be a straight-away from a point 3 1/2 feet to the right of post 1; the maximum left angle will appear to be a straight-away from a point 3 1/2 feet to the left of post 5. This applies to both doubles and singles shooting when the targets are 15 to 20 yards from the house.
Point 8 is where the center line of the trap house and the center line of the trap machine intersect.