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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
338 win mag, 300 win mag, or 300 weatherby mag?
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<blockquote data-quote="Bart B" data-source="post: 795729" data-attributes="member: 5302"><p>Thanks for posting a link to those World Open Relay Results.</p><p></p><p>I checked the cartridges used in the top 50 places of heavy gun group agg's. A rimless bottleneck round had about twice as many places as any belted round. Which is why I suggested the .300 WSM or similar large-capacity rimless cases.</p><p></p><p>Would be interesting to find out how those shooting belted cases resized them. Neck only, partial neck, full length with standard or bushing dies with or without expander balls. Decades ago, when 30 caliber belted magnums were "the" cartridge to use in 1000-yard prone matches, top competitors learned that new cases gave excellent accuracy. But any full length sizing of fired belted cases with a standard die did not get rid of the ridge right in front of the belt caused by the case body expanding at that point at peak pressure when the case head was hard against the bolt face. That ridge interferred with repeatable positioning of the back end of the case in the chamber. Even if fired belted cases were full length sized such that they headspaced on their shoulders, that ridge still caused accuracy problems. Standard dies do not size that ridge down; they stop about .010" or thereabouts in front of the belt.</p><p></p><p>A solution was to cut the top and bottom of a standard full length sizing die off making it a "body" die. It was set in the press to resize a full length sized fired case all the way, totally, to the belt swaging that ridge back down to body diameters; the case diameter at that point was virtually the same as new cases. Such resized fired belted cases shot just as accurate as new ones. Virtually the matches won and records set were done with such cases. Nowadays, a collet die's availible to do the same thing: <a href="http://www.larrywillis.com" target="_blank">Innovative Technologies - Reloading Equipment</a>.</p><p></p><p>After good quality 26 caliber bullets became available, the milder recoiling 6.5x.284 round became the favorite even though better BC bullets were available in 30 caliber. They still are today for shoulder fired rifles.</p><p></p><p>There really are belted 30 caliber magnums that'll shoot 1/4 MOA. . .at short range. Once in a while. And it's a popular thing to only tell others the smallest groups your hardware shoots. And benchresters seldom, if ever, published outside their range scoreboard the sizes of all groups/scores fired for each competitor. So we don't know exactly how big the largest groups/scores are. Even those 1000-yard single 5-shot groups are probably the smallest one ever fired by that rifle; all the others are larger. The group agg score numbers in the World Open Relay Results are typically about 2/3rds the size of the largest group in the series. And that agg record's probably the smallest one that rifle ever shot. Which means only 10 competitors kept all their record group shots under 10 inches. And if we superimposed each single group atop each other, the all-group composite would be larger; much larger.</p><p></p><p>All of which to me means, if your hardware shoots under 1 MOA all the time at 1000 yards, then you've got something special. And your best chance of doing it is to use rimless cases or a second body die on your belted ones.</p></blockquote><p></p>
[QUOTE="Bart B, post: 795729, member: 5302"] Thanks for posting a link to those World Open Relay Results. I checked the cartridges used in the top 50 places of heavy gun group agg's. A rimless bottleneck round had about twice as many places as any belted round. Which is why I suggested the .300 WSM or similar large-capacity rimless cases. Would be interesting to find out how those shooting belted cases resized them. Neck only, partial neck, full length with standard or bushing dies with or without expander balls. Decades ago, when 30 caliber belted magnums were "the" cartridge to use in 1000-yard prone matches, top competitors learned that new cases gave excellent accuracy. But any full length sizing of fired belted cases with a standard die did not get rid of the ridge right in front of the belt caused by the case body expanding at that point at peak pressure when the case head was hard against the bolt face. That ridge interferred with repeatable positioning of the back end of the case in the chamber. Even if fired belted cases were full length sized such that they headspaced on their shoulders, that ridge still caused accuracy problems. Standard dies do not size that ridge down; they stop about .010" or thereabouts in front of the belt. A solution was to cut the top and bottom of a standard full length sizing die off making it a "body" die. It was set in the press to resize a full length sized fired case all the way, totally, to the belt swaging that ridge back down to body diameters; the case diameter at that point was virtually the same as new cases. Such resized fired belted cases shot just as accurate as new ones. Virtually the matches won and records set were done with such cases. Nowadays, a collet die's availible to do the same thing: [url=http://www.larrywillis.com]Innovative Technologies - Reloading Equipment[/url]. After good quality 26 caliber bullets became available, the milder recoiling 6.5x.284 round became the favorite even though better BC bullets were available in 30 caliber. They still are today for shoulder fired rifles. There really are belted 30 caliber magnums that'll shoot 1/4 MOA. . .at short range. Once in a while. And it's a popular thing to only tell others the smallest groups your hardware shoots. And benchresters seldom, if ever, published outside their range scoreboard the sizes of all groups/scores fired for each competitor. So we don't know exactly how big the largest groups/scores are. Even those 1000-yard single 5-shot groups are probably the smallest one ever fired by that rifle; all the others are larger. The group agg score numbers in the World Open Relay Results are typically about 2/3rds the size of the largest group in the series. And that agg record's probably the smallest one that rifle ever shot. Which means only 10 competitors kept all their record group shots under 10 inches. And if we superimposed each single group atop each other, the all-group composite would be larger; much larger. All of which to me means, if your hardware shoots under 1 MOA all the time at 1000 yards, then you've got something special. And your best chance of doing it is to use rimless cases or a second body die on your belted ones. [/QUOTE]
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338 win mag, 300 win mag, or 300 weatherby mag?
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