The 400 yard groups 6 shot groups are usually a horizontal oval shape (wind) and I do have the 3 x 9 syndrome and hunting bullets, not target bullets.
You guys mentioned variable velocity rates, which could also be contributing, because I don't yet have a chrony.
So there is hope of improvement.
Thanks guys
Stray what kinda rig is this cartrige and rifle if you know the twist rate and what bullets are you useing
JBM I would realy love to hear you make these arguments to some of my shooting buddies one who I belive to be the best barrel maker in the world bar none.Second if twist rate is not a factor why do we have difrent twist rates I gave a example of a under rotation problem now how about a over 155 palma bullet out of a 1-10 and beef up the load the bullet will hold together but is as accurate as a pig in a poke. Lets also not forget hatchers note book and a section on spin drift!! what about the green hill formula
[ 10-28-2004: Message edited by: sdiehn ]
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the bullet will lose the amount of rotation that is need to keep it stable.This is why you have difrent twist rates for difrent leanght bullets
I have shot the 107 seirras out of a 243 witha twist of 1-11 at 100 yards they were tack drivers but at 200 they were all over the place this is a extreme case as the bullet should be shot threw a 1-9 twist and 10 would be marginal.
I would be willing to bet if you looked close at the targets when the load loses accuracy at a spacific range say a 400 yard target that you find that the holes are not round. you wil need to keep a specific RPS to keep the bullet stable
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the best gun for the job is the one you shoot best
<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>the bullet will lose the amount of rotation that is need to keep it stable.This is why you have difrent twist rates for difrent leanght bullets <HR></BLOCKQUOTE>
Yes, it loses rotation, but it also loses velocity. The forces that are attempting to yaw the bullet come from forward velocity. The forces maintaining stability come from rotation. The velocity forces fall faster than the rotation forces so the stability goes up as the bullet goes down range.
<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>JBM I would realy love to hear you make these arguments to some of my shooting buddies one who I belive to be the best barrel maker in the world bar none.Second if twist rate is not a factor why do we have difrent twist rates I gave a example of a under rotation problem now how about a over 155 palma bullet out of a 1-10 and beef up the load the bullet will hold together but is as accurate as a pig in a poke. Lets also not forget hatchers note book and a section on spin drift!! what about the green hill formula<HR></BLOCKQUOTE>
I never said that it wasn't a factor. I said that bullets that are stable at the muzzle tend to stay stable going downrange (again, all bets are off as they cross through the speed of sound). We have different twists to make different bullets stable at the muzzle. I don't deny spin drift exists - I've seen it with my .338/.416. Greenhill's formula I can do without. There are much better programs/formulas available.
Pick a reason and most of the time, combination of several.
Popular misconception, groups can tighten up at longer distance. Yes, and it is called a "freak accident", but it will not happen normally or more important repeatedly. if it will not shoot good at 100, no way it will shoot good at 500 or 1000.
What i was orginaly trying to get at was that a lot of times when you find a load out of a good gun that shoots great out to 300 -400 yards you will usely find that the bullet is marginal for the twist.Now if its a gun that has some throat erosion this will compond the problem
one of the guys i use to work with had a 240 NM with a 10 twist (this gun shot sub .250 5 shot groups) and shot the international 3 postion he went and practiced at 300 yards before going to Fort Benning the difrence was 300 yards to 300 meters that difrence with the fact the throat was on the way out was masive. He set the barrel back .060 not much for a bad throat and the gun begain to shot again this rifle even when he first built it would not shoot 600.
There are a lot of pricopals and formulas that peaple use as a absulute hard and fast rules. this has to be because the math or computer says so. But in all acuality the practical use and experiances are tottaly difrent.
My guess is that stray is useing a lite bullet in a faster twist barrel say 130`s in 30 cal. and a 10 twist or heavy bullets in a slow twist say 80 grainers in 223 cal. out of a 10 or slower twist.
When I try to diganose a problem their is a process that I go threw steps to find out what may be the problem one of the most commom problems you find is that shooters are useing the wrong bullets for what the barrel is set up for varmint bullets out of heavy game barrels or heavy game bullets out of varmint barrels
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