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Rifles, Reloading, Optics, Equipment
Reloading
Powder or primer degradation
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<blockquote data-quote="Canadian Bushman" data-source="post: 1988334" data-attributes="member: 41122"><p>There is a handful of things that blank primers.</p><p></p><p>Too much pressure - you have</p><p>Small cases with big firing pins - you have</p><p>Excessive headspace - dont know</p><p>Firing pins with improper shape - dont know</p><p>Too big of firing pin hole, loose - probably not</p><p>Thin cups on primers - dont know</p><p>Weak firing pin springs - dont know</p><p></p><p>I highly doubt firing pin length is your problem. The primer cup and anvil stop the firing pin not the stop collar. This is why the dent in you primer is usually shallower than firing pin protrusion. </p><p></p><p>You have two cases, with different head stamps, with severely flattened primers that are also punctured.</p><p></p><p>The cases with different headstamps that dont have severely flattened primers are nut punctured. </p><p></p><p>I can also tell by looking that you have a large dia firing pin. Much larger than is needed on such a small case. Common on older rifles. Also looks like it has a bit of an edge near the OD but cant see well enough.</p><p></p><p>Both high pressure and excessive headspace can make primers look flattened. Both can result in punctured primers.</p><p></p><p>Small cases build pressure faster than large cases. Primers push out of the pocket towards the boltface and over the firing pin much quicker.</p><p></p><p>Small cases are WAY more susceptible to pressure spikes due to volume or powder changes than large cases. 1gn variations to a 10gn charge is a 10% increase, to a 100gn charge its 1%.</p><p></p><p>Because only 2 cases have punctured primers, The same two with similar headstamps, the primers that are not punctured are neither flattened, cratered, or punctured.</p><p></p><p>Id say excessive pressure is most likely</p><p>Excessive headspace is 2nd</p><p>Wrong size or mis-shaped firing pin is 3rd</p><p></p><p></p><p>Check inside of bolt for primer bits</p><p>Check firing pin for flame cutting</p><p>Revert to starting charges and minimum headspace</p><p>Use fresh, thick cup primers</p><p>And im betting youll be just fine.</p><p></p><p>If you wanna be thorough, check the volume of the cases with punctured primers to one that isnt. If its smaller you know excessive pressure is the culprit.</p></blockquote><p></p>
[QUOTE="Canadian Bushman, post: 1988334, member: 41122"] There is a handful of things that blank primers. Too much pressure - you have Small cases with big firing pins - you have Excessive headspace - dont know Firing pins with improper shape - dont know Too big of firing pin hole, loose - probably not Thin cups on primers - dont know Weak firing pin springs - dont know I highly doubt firing pin length is your problem. The primer cup and anvil stop the firing pin not the stop collar. This is why the dent in you primer is usually shallower than firing pin protrusion. You have two cases, with different head stamps, with severely flattened primers that are also punctured. The cases with different headstamps that dont have severely flattened primers are nut punctured. I can also tell by looking that you have a large dia firing pin. Much larger than is needed on such a small case. Common on older rifles. Also looks like it has a bit of an edge near the OD but cant see well enough. Both high pressure and excessive headspace can make primers look flattened. Both can result in punctured primers. Small cases build pressure faster than large cases. Primers push out of the pocket towards the boltface and over the firing pin much quicker. Small cases are WAY more susceptible to pressure spikes due to volume or powder changes than large cases. 1gn variations to a 10gn charge is a 10% increase, to a 100gn charge its 1%. Because only 2 cases have punctured primers, The same two with similar headstamps, the primers that are not punctured are neither flattened, cratered, or punctured. Id say excessive pressure is most likely Excessive headspace is 2nd Wrong size or mis-shaped firing pin is 3rd Check inside of bolt for primer bits Check firing pin for flame cutting Revert to starting charges and minimum headspace Use fresh, thick cup primers And im betting youll be just fine. If you wanna be thorough, check the volume of the cases with punctured primers to one that isnt. If its smaller you know excessive pressure is the culprit. [/QUOTE]
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Powder or primer degradation
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