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Rifles, Reloading, Optics, Equipment
Reloading
264 WM heavy bolt lift
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<blockquote data-quote="bigedp51" data-source="post: 1185039" data-attributes="member: 28965"><p>So how many case greasers do we have here and are experts on the subject?</p><p></p><p>Did any of you ever hear about anyone who lubes his cases all the time complain about heavy bolt lift.</p><p></p><p>We seem to have a lot of experts who have no personal experience on the subject. Bolt timing effects the camming force during bolt lift and its breaking the case free of the chamber during primary extraction. Bolt thrust doesn't cause high chamber pressure. BUT high chamber pressure will cause brass to flow beyond its elastic limits and why you measure just above the extractor groove or belt for high pressure.</p><p></p><p> <img src="http://i122.photobucket.com/albums/o254/bigedp51/base%20expanshion_zpss3c0gjcm.png" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>The British used the base crusher system of pressure taking where a hollow copper crusher was used and the firing pin passed through the hollow copper crusher. The case was oiled in order for full chamber pressure to register on the copper crusher. These same rifle were proof pressure tested with two oiled proof cartridges. After proofing if the Enfield rifles headspace increased over .003 the rifle failed proof testing. At no time did firing oil cartridges cause hard bolt lift but it will cause lug setback and a increase in headspace.</p><p></p><p>Below is from the "1929 British Textbook of Small Arms" and to this day the British used two oiled proof cartridges to test their small arms.</p><p></p><p><img src="http://i122.photobucket.com/albums/o254/bigedp51/TBOSA2-1_zpsecf9f76c.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>Bottom line, well used older rifles might have a problem with hard bolt lift at the top of the upward bolt movement due to bolt wear. If what you said above was true all neck sized cases would cause hard bolt lift from the drag on the base of the case.</p></blockquote><p></p>
[QUOTE="bigedp51, post: 1185039, member: 28965"] So how many case greasers do we have here and are experts on the subject? Did any of you ever hear about anyone who lubes his cases all the time complain about heavy bolt lift. We seem to have a lot of experts who have no personal experience on the subject. Bolt timing effects the camming force during bolt lift and its breaking the case free of the chamber during primary extraction. Bolt thrust doesn't cause high chamber pressure. BUT high chamber pressure will cause brass to flow beyond its elastic limits and why you measure just above the extractor groove or belt for high pressure. [IMG]http://i122.photobucket.com/albums/o254/bigedp51/base%20expanshion_zpss3c0gjcm.png[/IMG] The British used the base crusher system of pressure taking where a hollow copper crusher was used and the firing pin passed through the hollow copper crusher. The case was oiled in order for full chamber pressure to register on the copper crusher. These same rifle were proof pressure tested with two oiled proof cartridges. After proofing if the Enfield rifles headspace increased over .003 the rifle failed proof testing. At no time did firing oil cartridges cause hard bolt lift but it will cause lug setback and a increase in headspace. Below is from the "1929 British Textbook of Small Arms" and to this day the British used two oiled proof cartridges to test their small arms. [IMG]http://i122.photobucket.com/albums/o254/bigedp51/TBOSA2-1_zpsecf9f76c.jpg[/IMG] Bottom line, well used older rifles might have a problem with hard bolt lift at the top of the upward bolt movement due to bolt wear. If what you said above was true all neck sized cases would cause hard bolt lift from the drag on the base of the case. [/QUOTE]
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Reloading
264 WM heavy bolt lift
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