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Rifles, Reloading, Optics, Equipment
Reloading
Cases seems to grow too much
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<blockquote data-quote="Hugnot" data-source="post: 2722831" data-attributes="member: 115658"><p>My AI rifles have shorter chambers that require new unformed brass to have a crush fit. Upon fire forming the brass expands in all directions but excessive case stretching is prevented by the crush fit - brass held firmly against bolt face by crush fit. Should I have a rifle chamber that allows a round to be chambered without a crush fit I would fireform with a bullet seated out to contact the leade. Subsequent loadings would require F/L sizing die adjustments to maintain minimum headspace.</p><p></p><p>Generally, AI cases require far less trimming than their parent case. A good example is the 6mm AI made from 6mm/.244 Remington brass that has a sloping body wall & 26-degree shoulder. Upon fireforming to the 6mm AI, the body taper is reduced to close to zippo & the shoulder angle is increased to 40 degrees. Fireforming is next with a nice firm crush fit. Using a trim length of .010 shorter than max case length trimming may be skipped for 5-7 loads & by then primer pocket expansion might result in cases being tossed.</p><p></p><p>Getting back to the OP's problem & guessing what happened with provided data. An existing cycle of excess stretching followed by trimming. I would suggest checking for a crush fit with new brass then if no crush fit, fire form with bullet seated out to contact leade then adjust F/L die to maintain minimum headspace.</p><p></p><p>The .284 is sort of an improved cartridge in that it has a 35-degree shoulder and little body taper. Expanding necks from .284 (ID) to .308 (ID) would reduce shoulder contact area. Should fireforming with bullets contacting not solve the problem the barrel might be set back & rechambered to provide a nice crush fit for unformed brass.</p><p></p><p>No problems with my COW formed 6mm AI. Has strong crush fit needing ground down shell holder - like jam them in tight for fireforming. Keep the ground down shell holder in the same box as the F/L die.</p></blockquote><p></p>
[QUOTE="Hugnot, post: 2722831, member: 115658"] My AI rifles have shorter chambers that require new unformed brass to have a crush fit. Upon fire forming the brass expands in all directions but excessive case stretching is prevented by the crush fit - brass held firmly against bolt face by crush fit. Should I have a rifle chamber that allows a round to be chambered without a crush fit I would fireform with a bullet seated out to contact the leade. Subsequent loadings would require F/L sizing die adjustments to maintain minimum headspace. Generally, AI cases require far less trimming than their parent case. A good example is the 6mm AI made from 6mm/.244 Remington brass that has a sloping body wall & 26-degree shoulder. Upon fireforming to the 6mm AI, the body taper is reduced to close to zippo & the shoulder angle is increased to 40 degrees. Fireforming is next with a nice firm crush fit. Using a trim length of .010 shorter than max case length trimming may be skipped for 5-7 loads & by then primer pocket expansion might result in cases being tossed. Getting back to the OP's problem & guessing what happened with provided data. An existing cycle of excess stretching followed by trimming. I would suggest checking for a crush fit with new brass then if no crush fit, fire form with bullet seated out to contact leade then adjust F/L die to maintain minimum headspace. The .284 is sort of an improved cartridge in that it has a 35-degree shoulder and little body taper. Expanding necks from .284 (ID) to .308 (ID) would reduce shoulder contact area. Should fireforming with bullets contacting not solve the problem the barrel might be set back & rechambered to provide a nice crush fit for unformed brass. No problems with my COW formed 6mm AI. Has strong crush fit needing ground down shell holder - like jam them in tight for fireforming. Keep the ground down shell holder in the same box as the F/L die. [/QUOTE]
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Reloading
Cases seems to grow too much
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