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Post by davet on May 3, 2015 8:15:39 GMT
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Post by tisme on May 3, 2015 8:25:00 GMT
Can you find me some 162 A max?
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Post by c18rch on May 4, 2015 14:55:42 GMT
Got some162s in stock. How many do you want?
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Post by tisme on May 4, 2015 18:41:29 GMT
Was going to re barrel the new howa but found out today it shoots really well without the mod! Now not sure if I should go 7-08 or not?
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Post by sako75varminter on May 4, 2015 20:02:42 GMT
Was going to re barrel the new howa but found out today it shoots really well without the mod! Now not sure if I should go 7-08 or not? Go for it Pete!!..you seemed most impressed by Rich's performance on the Sunday!!...
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Post by sako75varminter on May 4, 2015 20:03:19 GMT
Plus you will get a better barrel life!
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Post by tisme on May 5, 2015 7:36:39 GMT
But this barrel is brand new and only shot 120 rounds. It just wouldn't group at all, 4" at 100 yards, with the mod off I got 1/2". At first I thought it was the barrel so was going to re barrel but yesterday I found out it was the mod. Now I just need to work out if its the thread been cut badly or if its the mod itself. If I can get this shooting ok I've got a slot for a 7-08 so I'll buy another rifle (Tikka T3 sporter)
Sorry for going off topic
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Post by bryanlitz on Jun 17, 2015 10:38:06 GMT
I can appreciate what you guys are trying to do! Transonic stability is difficult to predict so the other approach is to 'shoot and see'. Unfortunately the issue requires a bit more data to be useful.
The biggest variable is altitude, or more specifically air density. Air density has the basic affect of slowing the bullet more or less but it also has an effect on stability. Thin air at high altitude will result in the bullet being more stable than the same bullet (fired from the same rifle) at lower altitude. Point being; a bullet that's transonic stable at 5,000 feet Above Sea Level may tumble at transonic speed at sea level. So if you say 'Bullet X' is transonic stable, you need to give the conditions that it was stable. I recall a thread some time ago where an epic argument formed up with two guys arguing that the 6mm 95 grain VLD was stable in a 1:9" twist. Turns out the guys saying it was stable lived at 4,000 feet ASL and the guy who observed it wasn't was at sea level. Of course if a bullet is transonic stable at sea level it will be so at higher altitudes as well (barring temperature extremes).
Another consideration is twist rate, and how well the bullet retains it's spin as it flies. Some riflings will slow down a bullets spin rate more than others; the bullets that can retain spin better arrive at transonic with more stability, so it's not just about the rifling twist rate, it also depends on spin retention.
Probably the single most important attribute of bullet design that's related to transonic stability is boat tail design. Bullets with shallow BT's (7 degrees or less) are more likely to remain stable in challenging conditions like transonic. Just going to 9 degrees can have an effect. Bullets with BT's in the 13 degree range will really struggle with stability. Of course BT isn't all there is to it; length and CG/CP matter as well but the BT is one quick easy way to get an idea.
Take care, -Bryan
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Post by tisme on Jun 17, 2015 14:15:09 GMT
Thats a lot more to think about. I'll start collecting a lot more data when I shoot from now on. Thanks
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Post by c18rch on Oct 16, 2015 8:07:27 GMT
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