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Rifles, Reloading, Optics, Equipment
Reloading
What the hell happened
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<blockquote data-quote="Hugnot" data-source="post: 2239583" data-attributes="member: 115658"><p>Looks like deterioration of 20 YO plus?, slightly compressed 4064 (long for diameter grains). Upon forming the shoulder longitudinal stress fractures (compression) were formed making for a gateway for corrosion for products of powder deterioration like nitric acid; blue-green copper oxide formed. Long term warm storage would speed deterioration.</p><p></p><p>My thinking:</p><p></p><p>The "stress fractures' would be formed at the point where the shoulder was formed from compression of brass at junction of body & shoulder. These tiny little cracks would be formed in a ring where the body was bent to form the shoulder and deterioration stuff penetrated there making for the blue/green stuff (copper oxide) erupting thru the case. About a 20 * bend stretching the outside & compressing the inside, same location in each round.</p><p></p><p>Above the junction of body & shoulder the stress fractures would run parallel to the axis of the case. Outside brass looks clean & shiny especially extractor grooves indicating interior chemical/corrosion action. Powder deterioration is an on-going process and compounds like calcium carbonate are commonly added to smokeless powders to ****** the deterioration. </p><p></p><p>When large amounts of powder is hoarded deterioration of same is a possibility but there appears to be no set short term time limit as temperature is a big factor.</p><p></p><p>In the mid 60's I used surplus H4831 apparently salvaged from pull down 20mm rounds & that stuff might have been 20 years old. Red & yellow cardboard box for less than $3.00 per pound. Many pounds of this were used in .270's.</p></blockquote><p></p>
[QUOTE="Hugnot, post: 2239583, member: 115658"] Looks like deterioration of 20 YO plus?, slightly compressed 4064 (long for diameter grains). Upon forming the shoulder longitudinal stress fractures (compression) were formed making for a gateway for corrosion for products of powder deterioration like nitric acid; blue-green copper oxide formed. Long term warm storage would speed deterioration. My thinking: The "stress fractures' would be formed at the point where the shoulder was formed from compression of brass at junction of body & shoulder. These tiny little cracks would be formed in a ring where the body was bent to form the shoulder and deterioration stuff penetrated there making for the blue/green stuff (copper oxide) erupting thru the case. About a 20 * bend stretching the outside & compressing the inside, same location in each round. Above the junction of body & shoulder the stress fractures would run parallel to the axis of the case. Outside brass looks clean & shiny especially extractor grooves indicating interior chemical/corrosion action. Powder deterioration is an on-going process and compounds like calcium carbonate are commonly added to smokeless powders to ****** the deterioration. When large amounts of powder is hoarded deterioration of same is a possibility but there appears to be no set short term time limit as temperature is a big factor. In the mid 60's I used surplus H4831 apparently salvaged from pull down 20mm rounds & that stuff might have been 20 years old. Red & yellow cardboard box for less than $3.00 per pound. Many pounds of this were used in .270's. [/QUOTE]
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What the hell happened
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