| Gun Characteristic | 6"/47 Gun | 5"/38 Gun | 40mm/56 Gun | 20mm/70 Gun |
|---|---|---|---|---|
| Designation | 6"/47 Mark 16 | 5"/38 Mark 12 | 40mm/56 Mk 1, Mk 2 and M1 |
20mm/70 Marks 2, 3 and 4 |
| Date Of Design | 1932 | About 1932 | 1941 | About 1939 |
| Date In Service | 1937 | 1934 | 1942 | 1941 (Mk2) |
| Gun Weight | 13,000 lbs. | 3,990 lbs. Without Breech |
Mk1: About 1,150 lbs. (3) Mk2: ( " ) M1: 1036.5 lbs. (4) |
150 lbs. (with breech) 46 lbs. (without breech) |
| Gun Length oa. | 300 in. | 223.8 in. | 148.8 in. | 87 in. |
| Bore Length | 282.3 in. | 190 in. | 88.6 in. | 55.1 in. |
| Rifling Length | 238.3 in. | 157.2 in. | 75.85 in. | 49.1 in. |
| Grooves | N/A | N/A | Mk1 & Mk2: (16), 0.0236" D x 0.220" W M1: (16), 0.0225" D x 0.220" W |
(9) 0.015" D x 0.205" W |
| Lands | N/A | N/A | 0.0892 in. | N/A |
| Twist | Uniform RH, 1 in 25 | Uniform RH, 1 in 30 | Increasing RH, 1 in 45 to 1 in 30 |
Uniform RH, 1 in 36 |
| Chamber Volume | 1,470 cu. in. | 654 cu. in. | 28.3 cu. in. | 2.127 cu. in. |
| Rate Of Fire Rds./Min. | 8 - 10 | W/o integral hoists: 12 -15 With integral hoists: 15 -22 |
120 per barrel nominal, 140-160 when horizontal (gravity assist) |
450 (Cyclic), 250-320 (Practical) |
| Working Pressure | 18.5 tons/sq. inch | N/A | N/A | N/A |
| Approx. Barrel Life | 750 - 1,050 rounds | N/A | N/A | N/A |
| Ammo stowage/gun | 200 rounds | N/A | N/A | N/A |
| Range | 6,000 yds, at 3.3 ° elev. (1) | 9,500 yds, at 10 ° elev. (2) | 6,800 yds, at 10 ° elev. (5) | 3,450 yds, at 10 ° elev. (6) |
| Range | 10,000 yds, at 6.5 ° elev. (1) | 13,400 yds, at 20 ° elev. (2) | 9,300 yds, at 20 ° elev. (5) | 4,275 yds, at 20 ° elev. (6) |
| Range | 20,000 yds, at 22.3 ° elev. (1) | 16,000 yds, at 30 ° elev. (2) | 10,690 yds, at 30 ° elev. (5) | 4,650 yds, at 30 ° elev. (6) |
| Range | 26,000 yds, at 44.5 ° elev. (1) | 17,200 yds, at 40 ° elev. (2) | 11,200 yds, at 40 ° elev. (5) | 4,775 yds, at 40 ° elev. (6) |
| Range | 26,118 yds, at 47.5 ° elev. (1 | 17,400 yds, at 45 ° elev. (2) | 11,130 yds, at 45 ° elev. (5) | 4,800 yds, at 45 ° elev. (6) |
| AA Ceiling | 48,000 feet | 37,200 feet | 22,300 feet | 10,000 feet |
| Notes: (1): With 130 lbs. AP, (2): With 55 lbs. AAC, (3): Water Cooled, (4): Air Cooled, (5): With 1.985 lbs. HE, (6): With 0.271 lbs. HE | ||||