USRE18137E - Priming mixture - Google Patents

Description

Reissued July 28, 1 931 UNITED STATES PATENT OFFICE JOSEPH MCNUTT, OF NEW HAVEN, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO WINCHESTER REPEATING ARMS COMPANY, OF NEW HAVEN, CONNEC- TICUT, A CORPORATION OF DELAWARE PRIMING MIXTURE No Drawing. Original No. 1,800,223, dated April 14,

1931, Serial No. 307,555, filed September 21, 1928.

'Application for reissue filed May 29, 1931. Serial No. 541,105.

This invention relates to improvements inpriming mixtures for small arms ammu n tion and more particularly to a non-corrosive priming mixture for rim fire cartridges.

In producing the priming mixture forming the subject matter of my invention, I employ a basic metallic nitrate as an oxygen supplying element, a metallic sulphocyanate as the fuel element and a metallic fulminate as the detonating element. To these ingredients I may add barium nitrate. I am aware that the use of a metal nitrate, a metal sulphocyanate and a metal fulminate together with ground glass or other suitable abrasive has been suggested in non-corrosive rim"fire"priming mixtures, but prior to my invention I am unaware of any prior noncorrosive priming mixtures containing a basic nitrate, alone or in combination with other substances. The basic nitrates, especially of the heavy metals, difi'er notably from the normal nitrates in their physical as well as their chemical properties. In general they are much less hygroscopic and also denser, both to such a degree that the normal nitrates and the basic nitrates, in particular those of lead, are by no means equivalents of each other as ingredients of priming mix-- tures. Priming mixtures containing normal lead nitrate Pb(NO have never been commercially successful owing to the great hygroscopicity of this salt and the resultant instability of priming mixtures containing it.

I have discovered that basic lead nitrate PbOH.NO has relatively so feeble a power of attracting moisture that priming mixtures containing it alone as the oxidizing agent or together with the other well known oxidizers are stable as well as efiicient.

A further difficulty with normal lead nitrate Pb(NO as an ingredient of priming mixtures is the fact that it has a relatively strong acid reaction in the presence of moisture. This together with its hygroscopic nature are the causes of the instability of such mixtures.

The basic nitrate of lead, PbOH.NO in the presence of moisture has a neutral or faintly alkaline reaction, and so, even it damp, it does not exert a decomposing influence on the mercury fulminate'or on the compounds as yet suggested as substitutes for the latter in converting corrosive priming mixtures into non-corrosive priming mixtures.

A suitable priming compound for rim fire use may be formed by mixing the ingredients in the following proportions:

Per cent Per cent Fulminate o1 mercury 40 Basic lead nitrate 30 12 Lead sulphocyanate. 12 10 Ground glass 22 21 Gum 1 1 Barium nitrate 113 The proportions of these ingredients may, of course, be varied, depending upon the commercial strength of the ingredients and to meet the requirements of various uses of the compound. The modification of the proportions with eventual omission of the glass for use in center fire primers is within the The mixture is then'poured into individual pellets of the proper size for the individual charges in the customary way by means of a charge plate provided with perforations adapted to mold pellets of the proper size. These pellets are then transferred to empty rim fire cartridge shells in the usual way and forced to distribute themselves into the hollow rims by spinning each shell in the customary machine. The shells are then loaded with powder and bullet in the cus tomary way. i

I claim: 1. A priming mixture comprising basic lead nitrate as an oxidizing ingredient. 2. A primin mixture comprising mercury m fulminate, baslc lead nitrate and a 'fuel ingredient.

3. A priming mixture comprising mercury fulminate, basic lead nitrate and lead sulphocyanate. u 4. A priming mixture consisting essentially of mercury fulminate, basic lead nitrate, a fuel and an abrasive.

5. A priming mixture comprising basic lead nitrate as its principal oxidizlng inso gredient, a fuel, and an abrasive.

6. A priming mixture comprising substantially 35 percent mercury fulminate, substantially 30 percent basic lead nitrate, substan- V tially 12 percent lead sulpho-cyanate and subg 25 stantia'lly 22 percent ground glass.

7. A priming mixture comprising substantially 40 percent mercury fulminate, substantially 12 percent basic lead nitrate, substantially 16 percent barium nitrate, substan- 3o tially 10 percent lead sulphocyanate and substantially 21 percent ground glass.

In testimony'whereof I afiix my si ature.

JOSEPH D. McN TT.