ES2978984T3 - Composition for single-base propellant powder for ammunition and ammunition provided with such composition - Google Patents

Abstract

The present invention relates to a composition for a single-base propellant powder for ammunition comprising nitrocellulose as the explosive base, an inert plasticizer component, at least one nitrocellulose stabilizing component, and optionally a flame-reducing component, and traces of one or more solvents and water. The aforementioned inert plasticizer component is dibutyl sebacate (DBS). Preferably, dibutyl sebacate is present at a content of between 2% and 7% by weight. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Composition for propellant powder of a single base for ammunition and ammunition provided with such compositionScope

The present invention relates to a single-base propellant powder composition for ammunition and to an ammunition provided with such a propellant powder composition.

In particular, the propellant powder composition according to the invention can be used in artillery ammunition, particularly in ammunition with a calibre between 40 mm and 155 mm.

State of the art

In general, a munition, both civil and military, consists of a projectile and a propellant charge. The propellant charge in turn consists of a so-called propellant powder and an ignition system.

The main element of the propellant charge is the propellant powder.

Propellant powders are classified according to the number of active components that constitute them, i.e. the number of explosive bases. The term “active component” or “explosive base” refers to a compound that can develop propulsion energy.

Depending on the number of explosive bases, conventional propellant powders are divided into four types:

- single-base, in which the active component (sole or main) is nitrocellulose;

- double-based, in which, in addition to nitrocellulose as the active component, there is also a nitroester, usually nitroglycerin;

- triple-base, in which the active components are nitrocellulose, a nitroester and a nitroamine (e.g. nitroguanidine); and

- multi-base, in which the active components are normally four: nitrocellulose, a nitroester and two nitroamines, generally nitroguanidine and cyclotrimethylenetrinitroamine (RDX).

Generally, high nitrogen nitrocellulose (known as guncotton) and medium nitrogen nitrocellulose (known as collodion cotton), usually obtained from cotton flakes or other plant forms, i.e. so-called tree nitrocellulose, are used in the production of propellant powders.

In addition to the active components, other components with a specific function are present in propellant powder compositions, as listed below: - plasticisers, which allow the workability of nitrocellulose; - stabilisers, designed to ensure the safety and stability of the propellant powder over time. In some cases, flash-reducing components may also be included directly in the propellant powder, in order to reduce the so-called muzzle flash of the weapon system.

The plasticizers used in single-base propellant powders are made up of inert materials, while in the other families, the nitroester, in addition to acting as an active component, also acts as a nitrocellulose plasticizer.

Currently, the plasticizers used in single-base propellant powders are dinitrotoluene (DNT) and dibutyl phthalate (DBP).

Dinitrotoluene (DNT), classified as a carcinogenic compound, has been subject, like all chemical compounds, to classification by the European Chemicals Agency (ECHA) and has been mandatorily banned both in production and use since 21 August 2015, without the possibility of repeal (Commission Regulation (EU) No 125/2012).

In addition, dibutyl phthalate (DBP) has been tested and classified as harmful to fertility and the unborn child (Commission Regulation (EU) No 143/2011 and related corrigenda). In this case, however, the date set for the end of its use, or 21 February 2015, has been postponed to 21 February 2027. The derogation is temporary and valid until the replacement/elimination of DBP.

In the field of ammunition, for reasons of occupational safety and the environmental impact of the chemicals used, it has become necessary to launch research programmes aimed at eliminating or replacing the two substances, dinitrotoluene (DNT) and dibutyl phthalate (DBP), from propellant powders, without, however, affecting their workability and performance.

To date, there are no known single-base propellant powder compositions for ammunition that are free of dinitrotoluene (DNT) and dibutyl phthalate (DBP) and at the same time guarantee workability and performance similar to those of propellant powders containing these two substances. “Workability” refers to both the ability of the composition to undergo a gelatinisation process, whereby the nitrocellulose mass coagulates into a gelatinous state (gel) without liquid separation, and the ability of the materials used to mix homogeneously and with stability over time. However, performance is related to the energy of the final composition, represented, for propellant powders, by the calorific value.

In addition to the composition, the geometry of the grains in which the propellant powder is formed also contributes to ballistic performance. Typically, a propellant powder grain is defined by typical dimensions (which vary from case to case): the number of longitudinal through holes, the diameter of the holes, the outer diameter and the length. For proper ballistic performance, it is essential that the holes are symmetrical and reproducible.

Obtaining propellant powder grains that have a well-defined geometry is directly related to the workability of the composition. This confirms the importance of the workability of a propellant powder composition.

US3785888 discloses a gas generating composition comprising 19% by weight of nitrocellulose, 1% by weight of ethyl acrylate and 3% by weight of dibutyl sebacate as a plasticizer. US3690970 discloses a single base powder comprising 93.8% nitrocellulose, 1.0% diphenylamine as a stabilizer and 4.7% dibutyl phthalate as a plasticizer. US 2016/244382 discloses that dibutyl phthalate (used as a burn rate modifier/plasticizer in propellants) is toxic and dibutyl sebacate is on a list of optional burn rate modifiers.

Therefore, in the ammunition field, there is a great need for a single-base ammunition propellant powder composition that is devoid of dinitrotoluene (DNT) and dibutyl phthalate (DBP), while at the same time having workability and performance similar to propellant powders containing these two substances.

Presentation of the invention

Therefore, the object of the present invention is to eliminate, in whole or in part, the drawbacks of the above-mentioned prior art by providing a single-base propellant powder composition for ammunition which is devoid of dinitrotoluene (DNT) and dibutyl phthalate (DBP) and which, at the same time, guarantees workability and performance comparable to conventional single-base propellant powders containing these two substances.

A further object of the present invention is to provide a composition for a single-base propellant powder for ammunition which is devoid of dinitrotoluene (DNT) and dibutyl phthalate (DBP) and which can be manufactured with production costs comparable to conventional single-base propellant powders containing these two substances.

The technical characteristics of the invention are clearly evident from the content of the claims provided below, and the advantages thereof will become more apparent in the detailed description that follows, in particular with reference to one or more preferred and non-limiting embodiments.

Detailed description

The present invention relates to a single-base propellant powder composition for ammunition and to an ammunition provided with such a propellant powder composition.

In particular, the propellant powder composition according to the invention can be used in artillery ammunition, particularly in ammunition with a calibre between 40 mm and 155 mm.

According to a general embodiment of the invention, the single-base propellant powder composition consists of:

- nitrocellulose as explosive base;

- an inert nitrocellulose plasticizer component;

- at least one nitrocellulose stabilizing component; and

- optionally, at least one flash-reducing component.

The propellant powder composition may also optionally contain traces of one or more solvents and water.

According to the invention, the above-mentioned inert plasticizer component consists of dibutyl sebacate (DBS). Dibutyl sebacate is present in the composition with a content of between 1% and 10% by weight based on the total amount by weight of nitrocellulose, nitrocellulose stabilizing component, inert plasticizer component and, if present, flash-reducing component.

In this case and in the rest of the description, the percentages (%) by weight of the individual components (including dibutyl sebacate as indicated above) refer to the dry part of the composition, “dry part” meaning the total components of the composition excluding any solvent and water. The content of any solvent and water is counted “out of one hundred”, i.e. as the number of parts by weight per 100 parts by weight of the total of all other components (dry part of the composition).

It has surprisingly been found that, in single-base propellant compositions, for the function of nitrocellulose plasticizer, dibutyl sebacate, with a content ranging from 1% to 10% by weight, can completely replace the conventional plasticizers used in single-base propellant powders, i.e. dinitrotoluene (DNT) and dibutyl phthalate (DBP), without compromising the workability of the composition or the final performance or stability of the propellant powder over time.

As already anticipated, “workability” is intended to mean both the ability of the composition to undergo a gelatinisation process, whereby the nitrocellulose mass coagulates into a gelatinous state (gel) without liquid separation, and the ability of the materials used to be mixed homogeneously and with stability over time. The material thus obtained can be stretched/extruded and subsequently subjected to a cutting process to give it a well-defined shape. Obtaining propellant powder grains having a well-defined geometry (essential as mentioned above to ensure ballistic performance) is directly related to the workability of the composition. Generally, as already mentioned above, a propellant powder grain is defined by typical dimensions (variable from case to case): the number of longitudinal through holes, the diameter of the holes, the external diameter, the length. For adequate ballistic behaviour it is essential that the holes are symmetrical and reproducible. This can only be achieved if the propellant powder composition can be worked in the direction specified above.

Furthermore, performance is related to the energy of the final composition, represented, for propulsion powders, by the calorific value.

As can be seen from the comparative examples in the description, the weight content of dibutyl sebacate in the propellant powder composition according to the present invention is not higher than the weight content of dinitrotoluene (DNT) and dibutyl phthalate (DBP) present in conventional single-base propellant powders. This means that the replacement of these two compounds by dibutyl sebacate (according to the present invention) does not require any reduction of the weight content of nitrocellulose in the composition and consequently no decrease in its calorific value (i.e. ultimately its performance) with respect to conventional propellant powders.

International safety regulations do not indicate any specific restrictions on use of dibutyl sebacate in terms of health safety. In particular, dibutyl sebacate is not classified as either a carcinogenic compound or a compound that is harmful to fertility and the fetus.

In light of what has been shown above, dibutyl sebacate is therefore a particularly suitable compound for the complete replacement of dinitrotoluene (DNT) and dibutyl phthalate (DBP) as inert plasticizer in single-base propellant powders.

In particular, it was established that, at a content of less than 1% by weight, the plasticizing action of dibutyl sebacate is not sufficient to guarantee the workability of the propellant powder during the production phase, since it turned out to be excessively viscous. At a content of more than 10% by weight, the plasticizing action of dibutyl sebacate is still effective, although the calorific value is negatively affected, thus affecting the energy yield of the propellant powder. In addition, for DBS percentages higher than 10% by weight, swelling phenomena may occur after extrusion.

Preferably, dibutyl sebacate is present in the composition at a content of between 2% and 7% by weight. Even more preferably, dibutyl sebacate is present in the composition at a weight content of between 3% and 5%. The different percentages of plasticizer affect the plasticity of the mixture during extrusion. It has been found that the preferred ranges indicated above make it possible to more easily obtain a correct extrusion of the composition and the subsequent size of the extrusion in propellant powder grains, without causing deformation phenomena of the extrusion either at the exit of the extruder or after the shearing phase.

As already noted above, the propellant powder composition according to the invention is single-base, in which the explosive base (or single active component) consists of nitrocellulose.

Preferably, the nitrocellulose is selected from nitrocelluloses with a high nitrogen content (known as guncotton) and nitrocelluloses with a medium nitrogen content (known as collodion cotton), usually obtained from cotton flakes or other plant forms, i.e. so-called tree nitrocellulose.

Preferably, the nitrocellulose is present at a weight content of between 82.5% and 98%. Even more preferably, the nitrocellulose is present at a weight content of between 89% and 94.5%. The energy, i.e. the calorific value, of the propellant powder is directly related to the nitrocellulose content, in addition to the nitrogen content thereof.

As already indicated above, the composition includes at least one nitrocellulose stabilizing component.

Advantageously, the nitrocellulose stabilizer mentioned above is selected from the group consisting of nitroamines, nitrosamines, ureas, derivatives of such compounds or mixtures thereof.

Preferably, among the nitroamines, the above-mentioned nitrocellulose stabilizer may be selected from diphenylamine and N-nitrosodiphenylamine, while from its derivatives it may be selected from 2-nitrodiphenylamine, 4-nitrodiphenylamine, N-nitroso-2-nitrodiphenylamine, N-nitroso-4-nitrodiphenylamine, 2,2'-dinitrodiphenylamine, 2,4-dinitrodiphenylamine, 2,4'-dinitrodiphenylamine, 4,4'-dinitrodiphenylamine, N-nitroso-2,4'-dinitrodiphenylamine, N-nitroso-4,4'-dinitrodiphenylamine, N-nitroso-2-nitrodiphenylamine, 2,2'-dinitrodiphenylamine, 2,4-dinitrodiphenylamine, 2,4'-dinitrodiphenylamine, N-nitroso-4-nitrodiphenylamine, 2,4-dinitrodiphenylamine, 2,4'-dinitrodiphenylamine, 4,4'-dinitrodiphenylamine.

Preferably, among the nitrosamines, the above-mentioned nitrocellulose stabilizer may be selected from dimethylnitrosamine and N,N-diethylnitrosamine.

Preferably, among the ureas, the above-mentioned nitrocellulose stabilizer may be selected from ethyl scintillate (1,3-diethyl-1,3-diphenylurea) and acardite (type I: 1,1-diphenylurea; type II: 1-methyl-3,3-diphenylurea), while among its derivatives it may be selected from 2-nitroethyl scintillate, 4-nitroethyl scintillate, 2,2'-dinitroethyl scintillate, 2,4-dinitroethyl scintillate, 2,4'-dinitroethyl scintillate, 4,4'-dinitroethyl scintillate, N-nitroso-N-ethylaniline, 2-nitro-N-ethylaniline, 4-nitro-N-ethylaniline, 4-nitro-N-nitroso-N-ethylaniline, 2,4-dinitro-N-ethylaniline.

Preferably, the at least one nitrocellulose stabilizing component mentioned above is constituted by ethyl phosphate (1,3-diethyl-1,3-diphenylurea). According to a particularly preferred embodiment of the invention, the composition comprises a single nitrocellulose stabilizing component, constituted by ethyl phosphate (1,3-diethyl-1,3-diphenylurea).

It has been experimentally proven that ethyl ester (1,3-diethyl-1,3-diphenylurea/EC), in addition to the stabilizing effect, also provides a plasticizing effect, actively contributing to the workability of the final mixture. In this way, it is possible to reduce the weight content of dibutyl sebacate (DBS), allowing the content of this component in the composition to be more easily brought to the preferred range of 2%-7%, or to the particularly preferred range of 3%-5%.

Preferably, said nitrocellulose stabilizing component is present with a content comprised between 1% and 5% by weight. Even more preferably, said stabilizing component is present with a content comprised between 2.5% and 3.5% by weight. In the above percentages by weight, it is possible to incorporate the stabilizer in the final composition in the appropriate quantity to guarantee the desired stability of the final product over time.

Advantageously, the composition may optionally comprise at least one flash-reducing component. Preferably, if provided, the at least one flash-reducing component mentioned above is present with a weight content of between 0.5% and 2.5%.

According to a preferred embodiment of the invention, the at least one flash-reducing component mentioned above is composed of potassium sulfate (K<2>SO<4>).

According to a preferred embodiment of the invention, the single-base propellant powder composition has the following formulation:

- nitrocellulose: 82.5%-98% by weight;

- dibutyl sebacate (DBS): 1%-10% by weight;

- stabilizing component (preferably ethyl ether): 1%-5% by weight;

- flash-reducing component: 0% to 2.5% by weight.

According to a particularly preferred embodiment of the invention, the single-base propellant powder composition has the following formulation:

- nitrocellulose: 89%-94.5% by weight;

- dibutyl sebacate (DBS): 3%-5% by weight;

- stabilizing component (preferably ethyl ether): 2.5%-3.5% by weight;

- flash-reducing component: 0%-2.5% by weight.

As already anticipated, the propellant composition may also optionally contain traces of one or more solvents and water. The content of any solvent and water is calculated as content in addition to the dry part of the composition, in terms of the number of parts of solvent per 100 parts of the total of other components of the composition. In particular, the total solvent content (including water) may reach up to 1.5 parts by weight per 100 parts of the dry part of the composition (nitrocellulose, plasticizer, stabilizer and, if present, flash reducer).

Examples of composition according to the invention

Propellant powder compositions have been produced for different types of ammunition.

In particular, single-base propellant powder compositions produced according to the invention are shown below for four different artillery munitions, the caliber of which is reported.

For some composition examples, a comparative example of a conventional single-base propellant powder composition used for the same ammunition is provided.

Example 1

A first example (Example 1) relates to a single-base propellant powder composition for 40 mm L70 calibre ammunition. The composition values are given in Table 1.

Table 1 - Example 1

Table 2 below shows data relating to a conventional single-base propellant powder composition used for the same ammunition.

Table 2 - Comparative example of M1 propellant powder

The propellant powder composition according to the invention was produced using the same production line and the same production parameters as the conventional one (M1) without any alteration of the finished product. The composition according to the invention thus presents a workability similar to the conventional one.

It has been found that the calorific value of the composition according to the invention is in line with the reference (M1), as well as the ballistic characteristics, in particular the velocity at the muzzle and the pressure developed in the weapon by the ammunition whose propulsion system provides for the use of the new propellant powder.

The composition of the propellant powder according to the invention has been subjected to physicochemical and ballistic characterization with complete success. This has confirmed that the composition of the propellant powder according to the invention guarantees a performance similar to the conventional one.

Example 2

A second example (Example 2) concerns a single-base propellant powder composition for 155 mm calibre ammunition, in particular for bottom-shot propellant charges. The composition values are given in Table 3.

Table 3 - Example 2

The propellant powder composition according to the invention was subjected to physicochemical and ballistic characterization with complete success. This has confirmed that the composition according to the invention has adequate workability and guarantees adequate performance.

Example 3

A third example (Example 3) relates to a single-base propellant powder composition for 100 mm calibre ammunition. The composition values are given in Table 4.

Table 4 - Example 3

Also in this case, the propellant powder composition according to the invention has been subjected to physicochemical and ballistic characterization with complete success. This has confirmed that the composition according to the invention has adequate workability and guarantees adequate performance.

Example 4

A fourth example (Example 4) concerns a single-base propellant powder composition for 76 mm L62 calibre ammunition. The composition values are given in Table 5.

Table 5 - Example 4

Table 6 below shows data relating to a conventional single-base propellant powder composition used for the same ammunition.

Table 6 - Comparative example of M6 propellant powder

The propellant powder composition according to the invention was produced using the same production line and the same production parameters as the conventional one (M6) without any alteration of the finished product. The composition according to the invention thus presents a workability similar to the conventional one.

It has been found that the calorific value of the composition according to the invention, as well as the ballistic characteristics, are in line with the reference (M6), in particular the velocity at the muzzle and the pressure developed in the weapon by the ammunition, whose propulsion system provides for the use of propellant powder according to the invention.

The composition of the propellant powder according to the invention has been subjected to physicochemical and ballistic characterization with complete success. This has confirmed that the composition of the propellant powder according to the invention guarantees a performance similar to the conventional one.

Example 5

A fifth example (Example 5) relates to a single-base propellant powder composition for 155 mm calibre ammunition, produced according to the invention. In this example, the composition is devoid of a flash-reducing component. The values of the composition are given in Table 7.

Table 7 - Example 5

Table 8 below shows data for a conventional single-base propellant powder composition used for the same ammunition.

Table 8 - Comparative example of propellant powder for 155 mm calibre The propellant powder composition according to the invention was produced using the same production line and the same production parameters as the conventional one without any alteration of the finished product. The composition according to the invention thus presents a workability similar to the conventional one.

It has been found that the calorific value of the composition according to the invention, as well as the ballistic characteristics, are in line with the reference, in particular the muzzle velocity and the pressure developed in the weapon by the ammunition, whose propulsion system provides for the use of the new propellant powder.

The propellant powder composition according to the invention was successfully subjected to physicochemical and ballistic characterization. This confirmed that the propellant powder composition according to the invention guarantees a performance similar to that of the conventional powder.

Advantageously, the single-base propellant powder composition for ammunition according to the invention can be obtained by the same production processes used to produce conventional single-base propellant powder compositions.

In particular, a solvent-based or solvent-free production process can be used.

In particular, the specific propellant powder compositions of Examples 1 to 5 above and their comparative examples were produced following a solvent production process.

In more detail, such propellant powders were produced according to the following production scheme (which should be understood as a purely non-limiting example):

- Stage 1: dehydration of nitrocellulose;

- Stage 2: mixing nitrocellulose with the other components of the composition;

- Stage 3: extrusion;

- Stage 4: solvent removal;

- Stage 5: drying;

- Stage 6: homogenization.

Dehydration is necessary to make nitrocellulose (NC) usable. In fact, for transport, NC has a water content of about 30%. For the mixing phase to take place efficiently, only solvents capable of gelatinizing NC must be present. In particular, for single-base powders, gelatinization of NC takes place using ethyl ether and ethanol, in the ratio of 65/35. Gelatinization is a process through which a partial solubilization of nitrocellulose occurs, through which a macromolecular superstructure is generated which, when evaporation is complete, leads to the final grain structure of the propellant powder.

The mixing of the nitrocellulose with the other components of the composition (step 1) was carried out in the presence of solvents (in particular water, alcohol and ether) to allow gelatinisation of the mixture of components and therefore to allow its workability. Gelatinisation is an exothermic phenomenon, so it is necessary to control the temperature inside the mixer with a water cooling system. The extrusion stage (step 3) occurs using certain moulds depending on the application, i.e. the type of ammunition for which the propellant powder is intended. The speed of the die can influence the final structure of the powder grain. The shear rate must be correctly adjusted to obtain powder grains with the desired length. The design of the mould for the die is very important, it must take into account the correct feeding, the stresses transmitted to the mould and the shrinkage of the propellant powder after drying. At this stage, the action of the plasticizer (DBS) is decisive, making it possible to extrude the propellant mixture through the die shells, so that the final grain maintains the geometric characteristics established in the design phase, to which the ballistic performance in subsequent use is associated. The homogenization stage (stage 6)

Stages 4 and 5 concern the reduction in the finished product of the content of all volatile substances used during the various stages of production. This has a dual objective: to preserve the ballistic characteristics of the final product and to make the product safer after the packaging phase.

If the propellant powder composition according to the invention is produced by a solvent production process, it may contain traces of solvents and water used in the production process. The total solvent content, i.e. solvents and water, used in the production process is such that it does not alter the chemical stability or performance over time. In particular, the total solvent content (including water) may reach up to 1.5 parts by weight per 100 parts of all other components of the composition (nitrocellulose, plasticizer, stabilizer and, if present, flash reducer).

The homogenisation stage (stage 6) allows a batch of gunpowder to be produced from a production batch. At this stage, the powder grains are mixed to ensure homogeneity of the powder batch and are packed into suitable containers.

In particular, the propellant powder composition according to the invention is in the form of extruded grains having a predominant longitudinal direction of development. Preferably, such grains are provided with a plurality of longitudinal through holes.

An object of the present invention is also an ammunition characterized by the fact that it is provided with a propelling powder having a composition according to the present invention and in particular as described above.

Advantageously, the ammunition mentioned above has a caliber between 40 mm and 155 mm.

Preferably, the ammunition has a caliber of 40 mm, 76 mm, 100 mm or 155 mm.

The invention provides many advantages already described in part.

The single-base propellant powder composition for ammunition according to the invention is devoid of dinitrotoluene (DNT) and dibutyl phthalate (DBP) and at the same time guarantees workability and performance similar to conventional single-base propellant powders containing these two substances.

The single-base propellant powder composition for ammunition is free of dinitrotoluene (DNT) and dibutyl phthalate (DBP) and can be produced by processes similar to those used to produce conventional single-base propellant powders. Production costs are therefore comparable to conventional single-base propellant powders containing dinitrotoluene (DNT) and dibutyl phthalate (DBP).

Therefore, the invention thus conceived achieves the above purposes.

Obviously, in its practical implementation, it can also adopt forms and configurations other than those described above without, for this reason, departing from the present scope of protection as defined in the claims.

Claims (13)

1. A single-base propellant powder composition for ammunition, consisting of nitrocellulose as explosive base, an inert plasticizer component, at least one nitrocellulose stabilizing component and, optionally, a flash-reducing component and traces of one or more solvents and water, characterized in that said inert plasticizer component consists of dibutyl sebacate (DBS), wherein the dibutyl sebacate is present in a content of between 1% and 10% by weight. 2. Composition according to claim 1, wherein dibutyl sebacate is present in a content between 2% and 7% by weight. 3. Composition according to claim 2, wherein dibutyl sebacate is present in a content between 3% and 5% by weight. 4. Composition according to one or more of the preceding claims, wherein said at least one nitrocellulose stabilizing component is selected from the group consisting of nitroamines, nitrosamines, ureas, derivatives of said compounds or mixtures thereof. 5. Composition according to one or more of the preceding claims, wherein said at least one nitrocellulose stabilizing component consists of 1,3-diethyl-1,3-diphenylurea. 6. Composition according to one or more of the preceding claims, wherein said nitrocellulose stabilizing component is present with a content comprised between 1% and 5% by weight. 7. Composition according to claim 6, wherein said nitrocellulose stabilizing component is present with a content between 2.5% and 3.5% by weight. 8. Composition according to one or more of the preceding claims, wherein nitrocellulose is present with a content between 82.5% and 98% by weight. 9. Composition according to claim 8, wherein nitrocellulose is present with a content between 89% and 94.5% by weight. 10. Composition according to one or more of the preceding claims, wherein said at least one flash-reducing component is present with a content comprised between 0.5% and 2.5% by weight. 11. Composition according to claim 10, wherein said at least one flash-reducing component consists of potassium sulfate. 12. Ammunition characterized in that it is provided with a propellant powder having a composition according to one or more of the preceding claims. 13. Ammunition according to claim 12, having a caliber between 40 mm and 155 mm, preferably a caliber of 40 mm, 76 mm, 100 mm or 155 mm.