US1825466A - Priming mixture - Google Patents

Description

rav s e patented Sept. 29, 1931 PATENT OFFICE JOSEPH D. MCNUTT, OF NEW HAVEN, CONNECTICUT, ASSIGNOR TO WINCHESTER RE- PEATING ARMS COMPANY, OF NEW HAVEN, CONNECTICUT, A CORPORATION OF DELAWARE PRIMING MIXTURE L'No Drawing.

This invention relates to priming mixtures for small arms ammunition and more particularly to non-corrosive priming mixtures. This application is a continuation in part of my copending application Serial No. 347,190,

filed March 14, 1929.

Heretofore rim fire priming mixtures have contained ground glass or other inert abrasive material to give the mixture sulficient harshness to permit it to properly function. Antimony sulphide, one of the commonly used fuels, also possesses a certain degree of abrasion, but no one heretofore has produced an operative priming mixture for rim fire cartridges without ground glass or other inert abrasive material, even though,

antimony sulphide were used as the fuel.

Various carbonates, and other basic compounds, both organic and inorganic, have also been added to priming mixtures as stabilizing agents. Among such compounds I have employed barium carbonate. Barium carbonate, and other carbonates, have heretofore been used in the form of impalpable powder and have performed no other function except that of a stabilizing agent.

I have found that Witherite, a natural occurring barium carbonate, may be employed as a stabilizing agent in priming mixtures in place of the artificially produced barium carbonate, and when it is so used with antimony sulphide an operative rim fire mixture may be produced without the use of ground glass or other inert abrasive material.

I have also found that witherite may be used to good advantage in place of artificially produced barium carbonate in priming mix tures for center fire cartridges.

A suitable mixture for rim fire use may be formed by mixing the ingredients of the following proportions:

The proportions of these ingredients may, of course, be varied, depending upon the commercial strength of the lngredients and to Application filed October 28, 1930. Serial No. 491,812.

meet the requirements of various uses of the priming mixture.

As stated above, an important feature of the present invention is the use of witherite to function both as a stabilizing agent and as an abrasive. Witherite is a mineral which is macro-crystalline and can thus be ground to any desired degree of granulation. When used in conjunction with antimony sulphide, which also functions to some extent as an abrasive, the use of ground glass in a rim fire mixture may be eliminated. As indicated above, the fuel employed may consist partly of antimony sulphide and partly of lead sulphocyanate. As is well known by those skilled in the art, lead sulphocyanate produces a greater amount of heat in a shorter space of time thanantimony sulphide and its use as a portion of the fuel facilitates combustion of the priming mixture upon detonation. Except for the presence of some antimony sulphide, within the minimum limits expressed, for the purpose of producing the necessary harshness in the priming mixture, I consider the use of these two fuels as the mere substitution of equivalents Within the skill of any explosives chemist.

In mixing the ingredients I first Weigh out the oxidizing agent, fuels and Witherite and mix them dry on paper. A small amount of a gum solution, preferably 1 percent, such as is generally used in wet mixtures, is then added and worked in briefly by hand. The Wet fulminate of mercury, containing approximately 16 percent of Water, is then Weighed out and added to the other ingredients and the whole mixed until a homogeneous mixture is obtained.

The mixture is then formed into individual pellets of the proper size for individual charges in the customary manner by means of a charge plate provided with perforations adapted to mold pellets of the proper size'and weight. These pellets are then transferred to empty rim fire cartridge shells in the usual way and forced to distribute themselves in the hollow rims by spinning each shell in the customary rim fire loading machine. The shells, after the priming mixture has dried, may then be loaded with powder and bullets in the customary way.

As stated above, the mineral characteristics of witherite permit the ground glass or other inert abrasive to be dispensed with and the necessary harshness for rim fire mixture obtained when the witherite is used in c011- junction with antimony sulphide as a part of the fuel. lVhile it functions as an abrasive at the time of the burning of the pri1ning mixture, it does not have the destructive abrasive effect on the bore of the firearm in which it is used that ground glass or other inert abrasive materials have. lVhile I am unable to distinctly state why the witherite may be present to function as an abrasive and still not produce the effect referred to above on the bore of the firearm, it may be stated that the witherite is probably converted into impalpable barium oxide at the temperature of the explosion, after it has performed its function as an abrasive.

For a center fire priming mixture, I may employ the following ingredients in substantially the following proportions:

Witherite 2%-5% (preferably 3.: Barium carbonate, less than 1% In forming the center fire mixture the ingredients are first mixed and the mixture then formed into individual )ellets of the proper size for individual charges in the customary manner by means of a charge plate provided with perforations adapted to mold pellets of the proper size and weight. These pellets are then transferred into primer cups of the proper size and the charged primer cups submitted to pressure in the usual manner and then loaded into empty shells. The shells, after the priming mixture has dried, may then be loaded with powder in the customary way.

lVhile I have specifically disclosed the use of basic lead nitrate and barium nitrate as oxidizing agents, other oxidizing agents may be substituted therefor. I prefer to employ an oxidizing agent having a non-corrosive residue and as an example of a material that may be substituted for the basic lead nitrate of the rim fire priming mixture disclosed above,

Mercury fuhninate 30 -4070 (preferably 35.5%) Barium nitrate 40%50% (preferably 4'. 7,.) Lead sulphocyanate 14%1D% (preferably 16 "a (preferably .5

I may mention the well known oxidizing agent, barium nitrate. hen barium nitrate is substituted for basic lead nitrate, certain changes in the proportions of the ingredients may be necessary to obtain the proper sensitiveness and priming capacity, but these details of proportion and the like are within the skill of the explosives chemist and specific examples thereof are therefore not included in this specification.

I claim:

1. A priming mixture comprising mercury fulminate, an oxidizing agent having a noncorrosive residue, a fuel and witherite.

2. A priming mixture comprising mercury fulminate, an oxidizing agent having a noncorrosive residue, antimony sulphide and witherite.

3. A priming mixture comprising mercury fulminate, an oxidizing agent having a noncorrosive residue, lead sulphocyanate and witherite.

l. A priming mixture comprising mercury fulminate, an oxidizing agent having a noncorrosive residue, antimony sulphide, lead sulphocyanate and witherite.

5. A priming mixture comprising mercury fulminate, basic lead nitrate, antimony sulphide and witherite.

6. A priming mixture comprising mercury fulminate, basic lead nitrate, antimony sulphide, lead sulphocyanate and witherite.

7. A priming mixture comprising 35 to 50% mercury fulminate, 23 to 33% basic lead nitrate, 5 to 15% lead sulphocyanate, 5 to 20% antimony sulphide, and 5 to 10% witherite.

8. A priming mixture comprising substantially 42.5% mercury fulminate containing approximately 16% of water, substantially 28% basic lead nitrate, substantially 10% lead sulphocyanate, substantially 12% antimony sulphide, and substantially 7.5% witherite.

9. A priming mixture comprising mercury fulminate, barium nitrate, lead sulphocyanate and witherite.

10. A priming mixture comprising substantially 35 to 50% mercury fulminate, l0 to 50% barium nitrate, 14K to 19% lead sulphocyanate, and 2 to 5% witherite.

11. A priming mixture comprising substantially 35.5% mercury fulminate, substantially 45% barium nitrate, substantially 16% lead sulphocyanate and substantially 3.5% wither- 1te.

12. A priming mixture comprising substantially 35.5% mercury fulminate, substantially 45% barium nitrate, substantially 16% lead sulphocyanate, substantially 8.5% witherite and substantially 5% barium carbonate.

In testimony whereof I aiiix my signature.

JOSEPH D. MoNUTT.