Slide 1SDZ Construction: M242 25mm Gun Inter-service Resident Range Safety Course (Intermediate) Slide 2August 2003 M2A3 Bradley Fighting Vehicle Slide 3August 2003 Marine Corps Light Armored Vehicle (LAV) with the M242 25mm gun M242 25mm Gun Slide 4August 2003 25mm Ammunition M792 HEI-T M791 APDS-T M793 TP-T M794M910 Slide 5August 2003 Weapon: Ammo Type: Impact Media: Distance X: Angle P: Distance W: Area A: Area B: Map Scale: Map Sheet: Map Series: Map Edition: Date: Name: Legend for 25mm Systems Slide 6August 2003 Constructing a 25mm SDZ Construct 25mm system SDZ for the M242 25mm gun firing the M792 (HEI- T) cartridge into armor. Dimensions of the SDZ for this weapon system are given in DA-PAM 385-63, Chapter 12, Table 12-5. Plot the firing point, target, and then establish the gun target line. Slide 7August 2003 Plot the firing point. Establish the gun target line. Plot the target. Slide 8August 2003 From Table 12-5, find Distance X (armor). Distance X = 6379m Annotate Distance X on the legend. At the firing point, measure 5° with a protractor from the left and right of the gun target line. 5° (ˆ 6400m) Distance X Slide 9August 2003 Draw tic marks as shown. To establish the Dispersion Area, draw a straight line from the firing position through each tic mark out to Distance X. This completes the Dispersion Area. 5° Dispersion Area Distance X Slide 10August 2003 For the Ricochet Area, on Table 12-5, find the measurement for Distance W (armor). Lightly draw lines perpendicular to the limits of the Dispersion Area. Distance W = (ˆ 1400m) Dispersion Area 1373m Distance X Slide 11August 2003 Draw tic marks at the measurement for Distance W on the lines just drawn. Dispersion Area Draw a straight line through the tic marks. On Table 12-5, find the measure- ment for Angle P. Angle P = 28° PP Distance X Slide 12August 2003 Draw tic marks. At the firing point, measure 28° from the left and right limits of the Dispersion Area to establish the Ricochet Area. Dispersion Area 28° PP Distance X Slide 13August 2003 This completes the Ricochet Area. Draw a straight line from the firing point through each tic mark just drawn. Dispersion Area 28° PP Distance X Slide 14August 2003 Draw a straight line from the firing point through each tic mark just drawn. Dispersion Area Ricochet Area Annotate the Ricochet Area (Distance W) on the legend. This completes the Ricochet Area. Distance X Slide 15August 2003 Dispersion Area Ricochet Area From the firing position, scribe an arc between the left and right limits of the Ricochet Area. Use Distance X as the radius. Erase unnecessary lines. Distance X Slide 16August 2003 Dispersion Area Ricochet Area From the firing position, scribe an arc between the left and right limits of the Ricochet Area. Use Distance X as the radius. On Table 12-5, find the measure- ment for Area A. Area A = 300m Erase unnecessary lines. Distance X Slide 17August 2003 Draw straight lines through the tic marks just drawn. Lightly draw lines perpendicular to the limits of the Ricochet Area. Dispersion Area Ricochet Area Draw tic marks at the measurement for Area A. Dispersion Area Ricochet Area Distance X Slide 18August 2003 Draw tic marks. At the firing point, measure 25° from the left and right limits of the Ricochet Area. From the firing point, draw straight lines through the tic marks. Dispersion Area Ricochet Area 25° Dispersion Area Ricochet Area Distance X Slide 19August 2003 On Table 12-5, find the measurement for Area B. Area B = 400m Lightly draw a line that extends the gun target line from Distance X. Dispersion Area Ricochet Area 25° Verify that the measurement for Distance X is correct; then place a tic mark at the measurement for Area B. Dispersion Area Ricochet Area Distance X Slide 20August 2003 Ricochet Area This completes Areas A and B. From the firing point, scribe an arc from the right and left limits of Area A using the measure- ment for Area B as the radius. 25° Dispersion Area Ricochet Area Distance X Slide 21August 2003 Ricochet Area This completes Areas A and B. Annotate Areas A and B on the legend. From the firing point, scribe an arc from the right and left limits of Area A using the measure- ment for Area B as the radius. To complete the SDZ, erase all unnecessary lines. Dispersion Area Ricochet Area Area A Area B Distance X Slide 22August 2003 Ricochet Area From the firing point, scribe an arc from the right and left limits of Area A using the measure- ment for Area B as the radius. Dispersion Area Ricochet Area Area A Area B Distance X This completes Areas A and B. Annotate Areas A and B on the legend. To complete the SDZ, erase all unnecessary lines. Slide 23August 2003 Weapon: M242 25mm Gun Ammo Type: M792 (HEI-T) Impact Media: Armor Distance X: 6379m (ˆ6400m) Angle P: 28° Distance W: 1373m (ˆ1400m) Area A: 300m Area B: 400m Map Scale: 1:50,000 Map Sheet: Map Series: Map Edition: Date: Name: Legend for 25mm Systems