Straighten or index

Charles,
I am somewhat limited by my equipment. The ammo that it produces is all under .002 runout. That is why I had to manufacture crookedness in the way that I did. But I can tell you that in my experience in straightening that there is a range in which moving the bullet is somewhat easier,I believe because of the rather large pressure ring that the bullet that I most commonly use has. I have also noticed that if one does not succeed in straightening a round in say two tries that the integrity of the neck tension seems to be damaged.

In Tony's book, he mentions the accuracy that he obtained with ammo that had tested quite a bit more crooked than I no how to manufacture without bending it. It seems to me that one issue is where on the bullet it was measured, because typically the closer to the tip one measures, the larger the number. The other issue was that he did not write about checking to see if the rounds were straightened by chambering, and if that happened, then the conclusion that he reached might have been different. It would seem to me that if the bullet is seated into the lands, that there may simply not be room in a typical benchrest chamber for it to be at much of an angle to the CL of the loaded round, but that if the bullet is seated so that it jumps, that this may be less the case. I did not do a test of that situation because I generally seat so that my bullets are marked to one degree or another. Is it possible that one reason that the double radius ogive bullets have become popular with some shooters (including myself) is that the part of the bullet that engages the lead angle, when they are seated into the rifling, is very close to parallel with the lead angle, and that this produces better centering and where it applies, more positive straightening as the bullet is forced into the rifling?
Boyd
 
It would seem to me that a long list of variables could apply to this issue. Things like a fairly new case which has not
work hardened in the neck area straightens with much less force than a well worn case. How agressive the FL sizing would
also play a part. A neck sized only cases would stay centered in the chamber much better. Then we have bullets that
are smaller at the forward bearing surface area. Bullets which are seated quite shallow in the case neck lack the same
radial support that a deeper seated bullet would have. How bullet runout is measured , meaning how it is supported when
measured can mean a lot. Some measuring setups simply don't tell the whole story.
 
excerpt from Harold vaughn

I have re-read the chapter on bullet cant in Harold Vaughn's book rifle accuracy facts. It seems as though if a bullet is made with a tapered after body before the ogive begins it will cant in the barrel irrespective of whether it exhibited any measurable run out to begin with. This can cause flyers. Commercially made bullets are more likely to have this tapered after body but custom made bullets are not immune. This canting I think is of greater concern than my original question regarding the straightening of rounds because if I am understanding his writing correctly the projectiles can still leave the barrel crooked even if they are loaded straight to begin with.

Any one interested in commenting on or dismissing Vaughn's writings on this ?

Andy.
 
I believe that there are some bullets, that are demonstrably accurate, that have a slight taper all the way to their pressure rings. Results can differ from what theory and mathematics tell us should happen. That is why we test. Yes?
 
About 6 months of testing

Yep testing is really the only way to gain definitive answers. If what this guy states is true he found out about the canting issue from about 6 months of testing. More than any bench rest shooter could be bothered doing. So my guess is that until we that is BR shooters begin addressing issues like this our progress may stagnate. Which is a shame because dropping those aggs is really what the game is all about.
Andy.
 
Andy Cross said:
So my guess is that until we that is BR shooters begin addressing issues like this our progress may stagnate. Which is a shame because dropping those aggs is really what the game is all about. Andy.
Click to expand...

Lots of BR shooters have tested this stuff, Andy. The fact that individuals come to different conclusions is influenced by many things..most of which have been touched on here. That two of BR's greats, Mr. Boyer and Mr. Radigan, have different views simply underscores this.

And as much as I respect Mr Vaughn's work, just because something is written does not make it fact in every situation. Substitute a different testing platform (rifle) and it's quite likely that Mr. Vaughn would have come to a different conclusion.

Good shootin'. :) -Al
 
Al Nyhus said:
Lots of BR shooters have tested this stuff, Andy. And as much as I respect Mr Vaughn's work, just because something is written does not make it fact in every situation. Substitute a different testing platform (rifle) and it's quite likely that Mr. Vaughn would have come to a different conclusion.

Good shootin'. :) -Al
Click to expand...
Something else Mr Nyhus didn't explain in doing this kind of test is that at the accuracy levels benchrest shooters insist on is that from the moment we break in a new barrel its accuracy potential is constantly degrading. Meaning, that a test of, say, 50 rounds of canted seatings vs. 50 rounds of perfectly seated bullets, we are not comparing apples to apples.

Set that test up, in a well designed tunnel, and in an 1.450" rail gun barrel and there may be some definitive results. Just shooting a bag gun on an open-air range, in a day long test where the environmental conditions are changing by the minute and I doubt if a lot could be told shooting benchrest tolerance chamber and brass.
 
Andy Cross said:
........So my guess is that until we that is BR shooters begin addressing issues like this our progress may stagnate. Which is a shame because dropping those aggs is really what the game is all about.
Andy.
Click to expand...

Hasn't stagnated in almost 60 years !!
 
Could be approaching it

Considering the way the aggs have dropped over the last 10 years I believe that we may be approaching a stagnation point. But I like to be optimistic in that sooner or later there will be another development that will see a shooter having to consistently agg 0.1 or lower to win anything.
 
Andy,
I don't believe that, the reason being that even if rifles scopes rests, bullets, and tune achieve perfection, there is still the atmosphere, the earth and the sun to deal with.
 
Boyd, just imagine the future, when they compete with lasers. Scoring will have to be electronic, and while there will likely be no rings (just distance from center), an approximation would be: diameter of X-ring, one micron, 10 ring, 2 microns, etc. Just human nature. Someone always wants to say "mine's bigger" -- Oops, that should be, uh, "better."
 
I'd use a different word

Boyd Allen said:
Andy,
I don't believe that, the reason being that even if rifles scopes rests, bullets, and tune achieve perfection, there is still the atmosphere, the earth and the sun to deal with.
Click to expand...

I think I would phrase that .... ,the earth and sun to accommodate. But once done the groups would be reduced yet again.
 
Yep

Yep
I re-entered the sport of short range BR shooting after a nearly 15 year absence. Also considering 1000 yard BR. The gear has changed with rifle configurations, wind flags, scopes etc but not much else in spite of it all. I was sure when I got back into it I was going to find that to win even a local club match you would need to agg in the low ones and be in the zero something for a match like the nationals.

So in one way I was relieved but in another way disappointed that this wasn't the case.

Andy.
 
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