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Rifles, Reloading, Optics, Equipment
Reloading
Neck Bushing Sizes
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<blockquote data-quote="entoptics" data-source="post: 1898145" data-attributes="member: 104268"><p>Using a 0.316 bushing seems a little big for a 0.284 bullet...</p><p></p><p>0.316 + 0.001 = 0.317 neck OD (brass will spring back a little after sizing)</p><p></p><p>I've used a ball micrometer on a dozen rifle calibers, and the thickest neck wall I've ever seen is 264WM at ~0.016". Most other calibers, including my 7mm Rem Mag are more like 0.014" - 0.015" (some as low as 0.0125"). The necks can thin even more from repeated firing and trimming.</p><p></p><p>So...</p><p></p><p>0.317 - (2 x 0.015) = 0.287 ID...</p><p></p><p>You'd need no spring back, and thicker than average neck walls to get down around the correct 0.001-0.002" neck tension of 0.282 - 0.283" inner diameter. e.g. 0.316 - (2 x 0.0165) = 0.283" ID</p><p></p><p>I'd just buy a smaller bushing. Probably .314". Do you have access to a ball micrometer? If so, just measure the neck walls in 4-6 places around the neck, get the average number and apply the above math to get a 0.282" - 0.283" neck ID.</p><p></p><p>I got <a href="https://smile.amazon.com/Anytime-Tools-Micrometer-Spherical-0-0001/dp/B01524DDIO/ref=sr_1_4?dchild=1&keywords=Ball+micrometer&qid=1588965840&sr=8-4" target="_blank">this one from Amazon</a>, and it works well down to 0.0003 or so.</p></blockquote><p></p>
[QUOTE="entoptics, post: 1898145, member: 104268"] Using a 0.316 bushing seems a little big for a 0.284 bullet... 0.316 + 0.001 = 0.317 neck OD (brass will spring back a little after sizing) I've used a ball micrometer on a dozen rifle calibers, and the thickest neck wall I've ever seen is 264WM at ~0.016". Most other calibers, including my 7mm Rem Mag are more like 0.014" - 0.015" (some as low as 0.0125"). The necks can thin even more from repeated firing and trimming. So... 0.317 - (2 x 0.015) = 0.287 ID... You'd need no spring back, and thicker than average neck walls to get down around the correct 0.001-0.002" neck tension of 0.282 - 0.283" inner diameter. e.g. 0.316 - (2 x 0.0165) = 0.283" ID I'd just buy a smaller bushing. Probably .314". Do you have access to a ball micrometer? If so, just measure the neck walls in 4-6 places around the neck, get the average number and apply the above math to get a 0.282" - 0.283" neck ID. I got [URL='https://smile.amazon.com/Anytime-Tools-Micrometer-Spherical-0-0001/dp/B01524DDIO/ref=sr_1_4?dchild=1&keywords=Ball+micrometer&qid=1588965840&sr=8-4']this one from Amazon[/URL], and it works well down to 0.0003 or so. [/QUOTE]
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Reloading
Neck Bushing Sizes
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