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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Different types of rifling and there uses.
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<blockquote data-quote="tim_w" data-source="post: 1350295" data-attributes="member: 11132"><p>Are you speaking of the part on Bartliens site in the Faq section? </p><p></p><p>If so that is not against or negative to gain twist from what I read. As I read it the negative part was specific in the comparison to button rifling and that the buttoning if not done very carefully can speed up and slow down in one barrel blank. Obviously a decrease would be disastrous. A increase and then decrease even worse. We already know just from looking that most buttons are not accurate to 0.1 of twist rate and it seems there are some that are up to 0.5 off expected.</p><p></p><p>Here is the quote near the end of the topic</p><p></p><p>"I feel even a slight gain twist will help accuracy wise and not hurt a jacketed bullet shooter as well." He directly quotes Pope a few times who was a proponent of gain twist.</p><p></p><p>I think it depends on the extreme of the gain in the twist for increasing the angle of the rifling. By changing the angle you are changing the engraving position on the bullet. With small amounts this IMO has little to no real world effect ( i.e. bench rest comps have been won with gain twist so they produce very small groups) But I think when you get past 1-1.5 increase the the angle change might become an issue. I honestly have never tested it. I have only used .5 to 1 inch increase in twist rate. Where I think it comes in handy is when you have thin jackets and fast twists. We have had issues in the past keeping a number of caliber bullets like the Berger hunting or j4 jackets together when vel get up there with the faster twists for these longer bullets.</p><p></p><p>I think in general and not going to extreme starting bullet a bit slower spin and increasing it has some benefits.</p><p></p><p>Rock has had a slight twist increase in most all his barrels for how long now? I think its only .5 gain but still its there.</p><p></p><p>I can not speak to the bore rider setup that had bullets with the driving bands and extreme gain twist of increasing 5 to 6 inch or more thru the barrel. I have no experince what so ever with that but I do understand the theory and what they were after just no first hand knowledge so I can not speak on it.</p><p></p><p>I think over all small to moderate gain twist has benefit as we get into these faster and faster twist to stabilize these heavier higher bc bullets as they just keep getting longer and longer not to mention mono bullets. In the case of jackets I think even more so. As with jackets and high vel you get into the same situation why gain twist worked well in lead. Also the slightly slower start into the lands IMO s never a bad thing. </p><p></p><p>Its also why I like a radius on the rifling on the nondriving edge. IMO it allows for a easier start into the lands and thus less peak pressure from the sudden friction. I know the barrels I have setup this way always are very fast and can take hotter loads.</p><p></p><p>I think 3 groove for maximum life and over all I like 5 groove as my standard goto with a radius on the trailing side of the land bore intersect. I do not think this combo has any positive effect on accuracy but slight benefit in vel and pressure and I guess copper fouling and does not stress the jacket as much.</p></blockquote><p></p>
[QUOTE="tim_w, post: 1350295, member: 11132"] Are you speaking of the part on Bartliens site in the Faq section? If so that is not against or negative to gain twist from what I read. As I read it the negative part was specific in the comparison to button rifling and that the buttoning if not done very carefully can speed up and slow down in one barrel blank. Obviously a decrease would be disastrous. A increase and then decrease even worse. We already know just from looking that most buttons are not accurate to 0.1 of twist rate and it seems there are some that are up to 0.5 off expected. Here is the quote near the end of the topic "I feel even a slight gain twist will help accuracy wise and not hurt a jacketed bullet shooter as well." He directly quotes Pope a few times who was a proponent of gain twist. I think it depends on the extreme of the gain in the twist for increasing the angle of the rifling. By changing the angle you are changing the engraving position on the bullet. With small amounts this IMO has little to no real world effect ( i.e. bench rest comps have been won with gain twist so they produce very small groups) But I think when you get past 1-1.5 increase the the angle change might become an issue. I honestly have never tested it. I have only used .5 to 1 inch increase in twist rate. Where I think it comes in handy is when you have thin jackets and fast twists. We have had issues in the past keeping a number of caliber bullets like the Berger hunting or j4 jackets together when vel get up there with the faster twists for these longer bullets. I think in general and not going to extreme starting bullet a bit slower spin and increasing it has some benefits. Rock has had a slight twist increase in most all his barrels for how long now? I think its only .5 gain but still its there. I can not speak to the bore rider setup that had bullets with the driving bands and extreme gain twist of increasing 5 to 6 inch or more thru the barrel. I have no experince what so ever with that but I do understand the theory and what they were after just no first hand knowledge so I can not speak on it. I think over all small to moderate gain twist has benefit as we get into these faster and faster twist to stabilize these heavier higher bc bullets as they just keep getting longer and longer not to mention mono bullets. In the case of jackets I think even more so. As with jackets and high vel you get into the same situation why gain twist worked well in lead. Also the slightly slower start into the lands IMO s never a bad thing. Its also why I like a radius on the rifling on the nondriving edge. IMO it allows for a easier start into the lands and thus less peak pressure from the sudden friction. I know the barrels I have setup this way always are very fast and can take hotter loads. I think 3 groove for maximum life and over all I like 5 groove as my standard goto with a radius on the trailing side of the land bore intersect. I do not think this combo has any positive effect on accuracy but slight benefit in vel and pressure and I guess copper fouling and does not stress the jacket as much. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Different types of rifling and there uses.
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