Title:
Primer mixture
United States Patent 2480141


Abstract:
This invention relates to primer mixtures and more particularly to rion-mercuric primer mixtures capable of performance equal to or superior to mercury fulminate now presently available. Itis an object of the invention to provide primer mixtures of the aforesaid non-mercuric character. It is...



Inventors:
King, William N.
Application Number:
US55666844A
Publication Date:
08/30/1949
Filing Date:
08/22/1944
Assignee:
FED CARTRIDGE CORP
Primary Class:
Other Classes:
149/41
International Classes:
C06B41/02
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US Patent References:



Description:

This invention relates to primer mixtures and more particularly to rion-mercuric primer mixtures capable of performance equal to or superior to mercury fulminate now presently available. Itis an object of the invention to provide primer mixtures of the aforesaid non-mercuric character. It is also an object of the invention to provide a primer mixture having a sensitivity equal or superior to that of mercury fulminate mixtures, one that is capable of uniform performance, and more particularly capable of stability at extreme climatic temperatures and under conditions of humidity approaching saturation.

It is particularly an object of the invention to overcome the instability manifested by mercuric primer mixtures under temperature conditions in excess of 100' F. and humidity in excess of 75% relative humidity. It is also an object of the invention to provide a primer mixture capable of satisfactory performance at sub-zero temperatures and one that will eliminate the difficulty of "blown primers," and that may be manufactured at a satisfactory cost as compared to the other primer mixtures available.

I have discovered that the aforesaid objects are fulfilled by a non-mercuric primer mixture wherein the primer explosive is basic lead styphnate. The primer mixture may desirably contain an oxidizer, a fuel, an explosive fuel and, if desired, a sensitizer. Throughout the present specification and claims all percentages given are on a dry weight basis, the entire composition being 100%.

The primary explosive, viz. basic lead styphnate is utilized in an amount representing 35-45% of the primer composition. As the oxidizer there may be utilized barium nitrate in an amount representing 37-47% of the mixture. In addition to the primary explosive and oxidizer there is used a fuel in an amount ranging from 12-22 % of the mixture. If desired, the fuel may be composed of a simple fuel in an amount ranging from 8-14% and an explosive fuel in an amount ranging from 3-9%. The sensitizer or catalyst is likewise included in an amount ranging from 0% to 2%.

As the oxidizer there may be utilized barium nitrate, lead nitrate, potassium chlorate, lead peroxide or other suitable oxidizing salt.

As the simple fuel there may be utilized antimony sulfide, lead sulfocyanate, copper sulfocyanate, calcium silicide, or metallic magnesium, aluminum, zirconium or other material capable of burning with flying embers.

As the explosive fuel there may be utilized nitrocellulose, grourp n gum eotton, powdered trinitrotoluene, nitrestarch or pentaerythritol tetranitrate, AS the seositizer (catalyst) there may be utilitd tetrs~ene or powdered glass.

An exemplary composition of the present invention is as follows Per cent Basic lead styphnate ------ ------ 40 ± 3 Barium nitrate --------------------- 42 3 Antimony sulfide ------------------11 ± 2 Nitrocellulose ------------------------ 6 ± 2 Tetracene: Range --------------------------0.3 to 5 Preferred range ------------------0.5 to 2 The aforesaid specific primer mixture is especially useful for shotgun shells. The mixture is loaded with an average dry weight of charge of 20 1.0 grain, utilizing a standard primer cup, standard battery cup with 0.090" flash hole and a standard anvil. The sensitivity of the primer of the present invention is about the same as the regular mercury fulminate primer mixture and may be varied by increasing or decreasing the amount of sensitizer in the mixture. Increased amounts of sensitizer increase the sensitivity of the mixture.

Ballistic tests show that this primer mixture can in general be used with the smokeless powders now in use, to give loads having a uniformity equal to or better than that encountered when utilizing the mercury primers heretofore available.

The primer mixture is particularly stable. Tests on primers stored at 110-120° F. and also at 140° F. with an 80-90% humidity show the nonmercuric primer of the present invention to be superior to standard mercury fulminate primers.

Tests made after cooling the loaded cartridges 4to -40° F. indicate no hangfires. Random firing gives good results with the non-mercuric primers of the present invention, and since it is less violent with the mercury fulminate primers it is helpful in eliminating blown primers. The cost of the primer mixture of the present invention compares favorably with the mercury fulminate mixtures, being equal to or less than the fulminate primer costs.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments herein except as defined by the appended claims.

What I claim is: 1. A non-mercuric primer mixture comprising basic lead styphnate in an amount ranging from 35% to not more than 45% of the total weight of the mixture, 39-45% oxidizer and a small percentage, not exceeding 5%, of sensitizer.

2. A non-mercuric mixture comprising basic' lead styphnate in an. amount ranging from- 3 7%o to 43% of the total weight of the mixture, 39-45% oxidizer and a small percentage, not exceeding 5%, of sensitizer.

3. A non-mercuric primer mixture comprising 37% to 40% basic lead styphnate, 39% to 45% ox- : idizer, 12% to 22% fuel and a small percentage, not exceeding 5%, of sensitizer. 4. A non-mercuric primer mixture comprising . 35% to less than 45% of basic lead styphnate, 37-47% of an oxidizer selected from the class consisting of barium nitrate, lead nitrate, potassium chlorate and lead perborate, 8-14% of fuel selected from the class consisting of lead sulfocyanate, copper sulfocyanate, calcium silicide, metallic magnesium, metallic aluminum and metallic zirconium, 3-9% of an explosive fuel selected from the class consisting of nitrocellulose, 2r, nitrostarch, ground gun cotton, powdered trinitrotoluene and pentaerythritol tetranitrate and 0-2% of a sensitizer selected from the class consisting of tetracene and powdered glass. : 5. A non-mercuric primer mixture having the following formula: Per cent Basic lead styphnate ----------------37 to 43 Barium nitrate ---- _____------------ 39 to 45 Antimony sulfide -------_-- ----- - 9 to 13 Nitrocellulose ---- -- ______ 4 to 8 Tetracene ------------------___0.2 to WILLIAM N. KING.

REFERENCES CITED The following references are of record in the file of this- patent: UNITED STATES PATENTS Number .1,312,156 1,889,116 1,905,796 1,928,208: 2,137,234 2,265,230 2,268,372 2,275,169* " 2,275,170 2,275,173 2,350,670 2,356,210 Name Date Buell -----_____- __ Aug. 5, 1919 Herz -------------- Nov. 29, 1932 Burus ------- Apr. 25, 1933 Large --- ------- Sept. 26, 1933 Brun -----___----- Nov. 22, 1938 Hitchens ---___--_ _ Dec. 9, 1941 Burrows --__------ Dec. 30, 1941 Brun-------------_ Mar. 3, 1942 Brn ----------____ Mar. 3, 1942 Brun: ----------- Mar. 3, 1942 Brun------------- June 6, 1944 Brun ---------- _ Aug. 22, 1944