Conversion of M3 and M4 charges 
Contents
M3 and M4 charges: description and tabular data
М3А1
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M3A1 propelling charge
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Charge M3 and M3A1 (green bag), zones 1–5
Purpose. The M3-series propellant charges are “green bag” charges for 155 mm howitzers, intended for firing in zones 1–5.
Description. The full charge contains approximately 2.49 kg of propellant: a base charge and four unequal increments in fabric bags. The bags are held together by four fabric straps sewn to the base and tied over the increment.
The M3 charge is assembled without flash-suppressor pads. The M3A1 charge has three flash-suppressor pads of potassium nitrate or sulphate: one of 57 g in front of the base charge and two of 28 g in front of charges 4 and 5.
M3A1 igniter — 99 g of flashless propellant (CBI) in a red cloth bag sewn to the rear of the base section. The M3 igniter is 85 g of black powder. On the M3A1 the seams of the base section are turned inside out so that the cloth edges are on the inside, which reduces residue after firing.
Differences between the models. The M3 has no flash suppressors. Its igniter is 85 g of black powder instead of CBI, and the seams of the base are not turned inside out.
Tabular data
| Parameter | Value |
|---|---|
| Type | green bag, separate loading |
| Weight | 2.81 kg |
| Length | 406 mm |
| Colour | green with black markings |
| Propellant | M1, 2.54 kg (explosive) |
| Guns | M1, M1A1, M45, M126, M126A1, M185, M199 |
Temperature limits
| Mode | Lower limit | Upper limit |
|---|---|---|
| Firing | −40 °C | +51,7 °C |
| Storage | −62.2 °C, no longer than 3 days | +71.1 °C, no longer than 4 hours a day |
M4A1 projectile charge
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M4A2 powder charge
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Charge M4A1 and M4A2 (white bag), zones 3–7
Purpose. For 155 mm guns, for firing in zones 3, 4, 5, 6 and 7.
Description. The full charge (M4A2) contains 5.90 kg of propellant, divided between the base charge and four unequal increments in white bags. The bags are joined by four straps sewn to the base and tied over the bag.
The M4A2 charge igniter is 99 g of flashless propellant (CBI) in a red cloth pad sewn to the bottom of the base charge. A flash-suppressor pad with 28 g of potassium nitrate or sulphate is placed at the front end of the base bag (bag 3). The seams of the base pad are turned inside out so that the cloth edges are on the inside, which reduces residue after firing.
Differences between the models. The M4A1 is similar to the M4A2, but its igniter is 85 g of black powder instead of CBI, the seams of the base charge are not turned inside out, and the charge has no flash suppressor. The M2 flash suppressor can be used with the M4A1 charge if needed, but it is issued separately.
Tabular data (full charge)
| Parameter | Value |
|---|---|
| Type | separate loading, white bag |
| Weight | 6.35 kg |
| Length | up to 533 mm |
| Colour | white with black markings |
| Guns | M1, M1A1, M45, M126, M126A1, M185, M199 |
| Propellant M1 | 6.08 kg (explosive) |
Temperature limits
| Mode | Lower limit | Upper limit |
|---|---|---|
| Firing | −40 °C | +51,7 °C |
| Storage | −62.2 °C, no longer than 3 days | +60.6 °C, no longer than 4 hours a day |
Restriction. ⇒ When firing an M4-series charge in zones 3 and 4, results may be unstable in range, so for these zones the M3-series “green bag” charge should be used when it is available.
Comparison of old propellant charges with modular ones
Table of weight, dimensions, chemical composition of the propellants and muzzle velocity.
Thanks to these data a replacement for the propellant charge can be selected.
| Charge | Type | Zones | Weight, kg | Propellant (grade, kg) | Length, mm | Muzzle velocity, m/s |
|---|---|---|---|---|---|---|
| M3 / M3A1 | green bag | 1–5 | 2,81 | M1, 2,49 | 406 | ≈207–372 (charges 1–5) |
| M4A1 / M4A2 | white bag | 3–7 | 6,35 | M1, 5,90 | 533 | 274–564 (charges 3–7) |
| M119 / M119A1 | white bag | 8 | 10,4 | M6, 9,30 | 660 | 684 |
| M119A2 | red bag | 7 | 10,66 | M6, 9,48 | 737 | ≈690 |
| M203 | red bag | 8S | 11,8 | M30A1, 11,8 | 768 | 826 |
| M203A1 | combustible case | 8S | 14,06 | M31A1, 12,7 | 768 | 826 |
| M231 | module (MACS) | 1–2 | 1,93 | PAP-7993, 1,59 | 152 | ≈301 / ≈450 (1 / 2 modules) |
| M232 | module (MACS) | 3–5 (6) | 2,65 | M30A1, 2,25 | 156 | ≈547 (3 modules) |
| BC-E | module (BMCS) | 1–2 | 1,9 | single-base, 1.5 | 155 | 315 / 470 (1 / 2 modules) |
| TC-F | module (BMCS) | 3–6 | 2,8 | tri-base, 2.3 | 177 | 560 / 690 / 822 / 940 (3 / 4 / 5 / 6 modules) |
| TCME 101 | module (BMCS) | 1–2 | 2,1 | single-base | — | — |
| TCME 100 | module (BMCS) | 3–6 | 2,8 | multi-base | — | — |
| DM82 / DM82A1 | module (DM) | 1–2 | — | — | — | — |
| DM72 / DM92 | module (DM) | 3–6 | — | — | — | 810 (5 modules, 39 cal.) / 945 (6 modules, 52 cal.) |
Notes. The muzzle velocity depends on the gun, the projectile, the charge temperature and barrel wear, so approximate values are given. The sign “≈” marks estimated or calculated data.
M3A1 (charges 1–5) — an estimate based on old ballistic data for the M107 projectile. M4A1 / M4A2 — manufacturer's requirements for 155 mm/23 cal. howitzers. M119 / M119A1 — charge 8, M107 projectile. M119A2 — nominal velocity from a 39 cal. howitzer. M203 and M203A1 — 826 m/s, according to the US Army procurement description.
M231 and M232 — calculated values for the M107 projectile from the M114 howitzer (23 cal.); for M232 only zone 3. BC-E and TC-F — data from the manufacturer MSM for a 52 cal. gun and a 23 L chamber; module weights are also from MSM. DM72 / DM92 — Nitrochemie / Rheinmetall requirements for the average velocity with the L15A1 projectile at 21 °C. For TCME 100 / 101 the weight is the net module mass and the propellant type is from the Nexter Munitions catalogue; no lengths or muzzle velocities are available in open sources. For DM82A1 no open data on weight, dimensions or velocity were found.
Read also on this site
Conversion of propellant charges
Conversion of M3 and M4 charges
Conversion of M119 charges
Conversion of M203 and M203A1 charges
Conversion of MACS charges (M231 and M232)
Modular charge system
MCS and BMCS modular charge systems: what is the difference
Propellant charges — all pages of the section
Informative content — all articles of the section
Oleh Syrota (Georgich©) for the Armed Forces of Ukraine /
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