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Rifles, Reloading, Optics, Equipment
Reloading
Best coyote bullet for .22-250
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<blockquote data-quote="Trickymissfit" data-source="post: 455955" data-attributes="member: 25383"><p>I don't know if you picked up on the part where I stated that I was in the camp that felt that the gyroscopic effect was more important than anything else. I chased the spin envelope for years, and results were fair, but also never got over the top. Walt said that he felt it took 179K rpm to stabalize a VLD bullet on impact, and the idea worked fairly well in my eyes, but never produced those bug hole groups I so much sought after. Yet shortly after that statement it was also discovered that a bullet with a .0001 displacement in it's C/G would also be about .093" out of the place of aim. But even more critcle was the fact that the faster you spun the bullet the further this displacement was down range. (this was about the time I decided it was time to start all over.) After a few conversations with the Fairland bunch I soon learned that I was operating on another planet, and the bullet shape and correct rifeling was far more important. Later I learned from some folks that make bullets about a couple of formulas they work with, and how to use them. (keep in mind I'm still a novice with this concept). I now know that over stabalization is just as bad as understabalization when it comes to group size. But even then they all operate in a window that seems always to be there. Most benchrest shooters now are using these formulas that came from the bullet makers in the first place. But I also have noticed that many folks operate with a different set of numbers, but use the same bullets. (I think this is to further confuse my old brain)</p><p> </p><p>Now back to the 53 grain bullet a bit. Someone said it has a B/C of .290, and the diameter is .223 (or .224 as that's not all that important). I get a 1.30 number with a .223 diameter. That's just barely in the 1:12 envelope, but not good enough for a 1:14 twist. But that won't always work. Most guys use a guide number (I prefer the term factor), and will multiply the 1.30 with their own set number. I like .80, but may move it up to .85 or even .87. These results show a 1:10 twist rate to be ideal. And I do believe that's why there has been some success with 1:9 twist barrels as the twist is about perfect. In otherwords a bullet that was a perfect design for a Savage .223 using a 1:9 twist rate. So I then did some calculations with the generic Sierra #1365 bullet. It's well known to print very tight groups in a 1:12 twist barrel. I made some measurments and plugged in the formula, and Bingo the numbers match the barrel twist perfectly. So now I'm at least moving in the right direction (I hope I am!). This leads me into the next paragraph (I know it's long)</p><p> </p><p>I go out to the garage and bring in four tubs of custom built 6mm and .223 bullets. Each tub is a different bullet, and these bullets have won a lot of matches in the midwest. I got these for doing some machine work for a well known bullet maker who may be gone to meet his maker. He told me that they were for 1:14 twist barrels (all eight tubs were), and were made off his custom built carbide swedging dies. I made measurments and the numbers were near perfect for a 1:14 twist barrel with each set (the 6mm's were 68 and 70 grains and the 22's were 50 and 53 grains), and maybe a 1:14.5 would have been perfect. I'll be doing some experimenting this spring with this new database, and will try to keep us posted on my findings. But for sure I've learned that the twist rate is much more important than the velocity of the bullets</p><p>gary</p></blockquote><p></p>
[QUOTE="Trickymissfit, post: 455955, member: 25383"] I don't know if you picked up on the part where I stated that I was in the camp that felt that the gyroscopic effect was more important than anything else. I chased the spin envelope for years, and results were fair, but also never got over the top. Walt said that he felt it took 179K rpm to stabalize a VLD bullet on impact, and the idea worked fairly well in my eyes, but never produced those bug hole groups I so much sought after. Yet shortly after that statement it was also discovered that a bullet with a .0001 displacement in it's C/G would also be about .093" out of the place of aim. But even more critcle was the fact that the faster you spun the bullet the further this displacement was down range. (this was about the time I decided it was time to start all over.) After a few conversations with the Fairland bunch I soon learned that I was operating on another planet, and the bullet shape and correct rifeling was far more important. Later I learned from some folks that make bullets about a couple of formulas they work with, and how to use them. (keep in mind I'm still a novice with this concept). I now know that over stabalization is just as bad as understabalization when it comes to group size. But even then they all operate in a window that seems always to be there. Most benchrest shooters now are using these formulas that came from the bullet makers in the first place. But I also have noticed that many folks operate with a different set of numbers, but use the same bullets. (I think this is to further confuse my old brain) Now back to the 53 grain bullet a bit. Someone said it has a B/C of .290, and the diameter is .223 (or .224 as that's not all that important). I get a 1.30 number with a .223 diameter. That's just barely in the 1:12 envelope, but not good enough for a 1:14 twist. But that won't always work. Most guys use a guide number (I prefer the term factor), and will multiply the 1.30 with their own set number. I like .80, but may move it up to .85 or even .87. These results show a 1:10 twist rate to be ideal. And I do believe that's why there has been some success with 1:9 twist barrels as the twist is about perfect. In otherwords a bullet that was a perfect design for a Savage .223 using a 1:9 twist rate. So I then did some calculations with the generic Sierra #1365 bullet. It's well known to print very tight groups in a 1:12 twist barrel. I made some measurments and plugged in the formula, and Bingo the numbers match the barrel twist perfectly. So now I'm at least moving in the right direction (I hope I am!). This leads me into the next paragraph (I know it's long) I go out to the garage and bring in four tubs of custom built 6mm and .223 bullets. Each tub is a different bullet, and these bullets have won a lot of matches in the midwest. I got these for doing some machine work for a well known bullet maker who may be gone to meet his maker. He told me that they were for 1:14 twist barrels (all eight tubs were), and were made off his custom built carbide swedging dies. I made measurments and the numbers were near perfect for a 1:14 twist barrel with each set (the 6mm's were 68 and 70 grains and the 22's were 50 and 53 grains), and maybe a 1:14.5 would have been perfect. I'll be doing some experimenting this spring with this new database, and will try to keep us posted on my findings. But for sure I've learned that the twist rate is much more important than the velocity of the bullets gary [/QUOTE]
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Best coyote bullet for .22-250
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