A perfectly straight loaded round with .0000 bullet run-out might be the goal but has anyone done any group testing to try and measure the impact on accuracy of say .0005....to .0015 run-out? I other words, when is enough...enough?
Ben
Ben
Concentricity impact on accuracy
- Thread starter BenPerfected
- Start date
Many years ago I did some testing with the M14 shooting the national match course. I shot ten 600 yard matches during the year with one ten shot string with the straight ammo and the second ten shot string with the crooked ammo (alternating from match to match). The straight ammo scored very slightly higher on the average but not enough to be statistically significant. You may get different results with something demanding higher accuracy like F Class or bench rest. The problem is getting someone to invest the effort to obtain enough data to do a meaningful statically analysis.
OP, I have noticed no difference in 1K yd accuracy with runout equal-to or less than .001", versus .003", with loads Jammed .010. Seymour
;D ;D
;D ;Dtom said:
Tom, That's so true, not to mention hilarious. Seymour
Keith Glasscock
Gold $$ Contributor
I disagree, the guys that beat me regularly, I'm sure use all three. They also weight sort everything - Brass, bullets, and cases, and use a seating depth checker that is accurate to .0001"
It can't be that I'm not good enough at reading the wind...
It can't be that I'm not good enough at reading the wind...
Northridge
Gold $$ Contributor
I do have all said equipment in my reloading but other than cataloging data I'm not sold as to it defining my loaded ammo potential. I let my target decide what is a success or not and often I'm coloring outside the lines for the best results on paper.
don't get stuck in a rut!!!!
Shawn Williams
don't get stuck in a rut!!!!
Shawn Williams
Let's assume that your concentricity checker shows you are loading crooked rounds. It shows this with new brass and bullets and also the same after several loadings. This begs the questions(s):
How does it keep getting crooked?
What can you do about it?
How crooked does it have to be to affect accuracy?
AND----a depth gage that measures in TEN THOUSANDTHS? Bud those guys are beating you because they are better shooters and have blown so much smoke up your ___ you can no longer see to aim................
Answers:
It gets crooked from one or more reasons--
"C" or "O" press out of alignment-- a press that floats the head of the cartridge cannot be suspected --some brands that do this can be had from Forster and Corbin. The price tag on a "C" or "O" press can be some indication that extra care was taken to assure that misalignment does not happen, but is no guarantee. Using an Arbor press can help a lot--using a center mounted turret press can hurt a lot.
It gets crooked due to poor alignment of the chamber/bolt head or barrel/receiver join--pretty common with non-custom rifles--Savage's floating bolt head helps some-custom built to very close tolerances rifle are even better.
Both these problems defy easy and inexpensive fixes. Either you shoot your crooked rifle or you shoot your crooked cartridge and the next loading you are back to square one......and that is only if it really matters---which is not proven anyway.
----or-----
Money spent chasing this wild goose could be better spent on building more ammo to practice with--or getting professional help with your bench manners or stance or ---mental balance or whatever--buying wind flags-- saving up for a REAL match rifle custom built by a pro. the list goes on--
BTW, you might have noticed the short fat cartridges have pretty well taken over BR shooting and some other disciplines as well--if you think about it--in the type of shooting where misalignment could very well cost you a tenth of a MOA and therefore make the difference between first or fifth or tenth place in a match the shorts rule. When you compare the radius of angle in a .001" misaligned .30-06 cartridge to the same thing in a 6ppc cartridge, you'll see that the tip of the bullet is further from center of the bore in the .30-06, if things were allowed to get that far off.
I suspect that most other BR and similar discipline shooters have abandoned their case gages, too--if you are using good equipment this is a non-issue........
How does it keep getting crooked?
What can you do about it?
How crooked does it have to be to affect accuracy?
AND----a depth gage that measures in TEN THOUSANDTHS? Bud those guys are beating you because they are better shooters and have blown so much smoke up your ___ you can no longer see to aim................
Answers:
It gets crooked from one or more reasons--
"C" or "O" press out of alignment-- a press that floats the head of the cartridge cannot be suspected --some brands that do this can be had from Forster and Corbin. The price tag on a "C" or "O" press can be some indication that extra care was taken to assure that misalignment does not happen, but is no guarantee. Using an Arbor press can help a lot--using a center mounted turret press can hurt a lot.
It gets crooked due to poor alignment of the chamber/bolt head or barrel/receiver join--pretty common with non-custom rifles--Savage's floating bolt head helps some-custom built to very close tolerances rifle are even better.
Both these problems defy easy and inexpensive fixes. Either you shoot your crooked rifle or you shoot your crooked cartridge and the next loading you are back to square one......and that is only if it really matters---which is not proven anyway.
----or-----
Money spent chasing this wild goose could be better spent on building more ammo to practice with--or getting professional help with your bench manners or stance or ---mental balance or whatever--buying wind flags-- saving up for a REAL match rifle custom built by a pro. the list goes on--
BTW, you might have noticed the short fat cartridges have pretty well taken over BR shooting and some other disciplines as well--if you think about it--in the type of shooting where misalignment could very well cost you a tenth of a MOA and therefore make the difference between first or fifth or tenth place in a match the shorts rule. When you compare the radius of angle in a .001" misaligned .30-06 cartridge to the same thing in a 6ppc cartridge, you'll see that the tip of the bullet is further from center of the bore in the .30-06, if things were allowed to get that far off.
I suspect that most other BR and similar discipline shooters have abandoned their case gages, too--if you are using good equipment this is a non-issue........
Anyone doing any testing won't help.
An actual scientific method applied to actually answer the question, would be very difficult/expensive to pull off.
For example, you would need test barrels finished with representative cartridges of varying length/width, each with test barrels finished at different tolerances/FB/throats, then you get into bullet ogives & length, load development to baselines, reload sizing systems for various amount of separated body runout to neck only to bullet seated only runouts and headspacings and pin striking.
All this before any notions across the gamut could hold as credible.
An actual scientific method applied to actually answer the question, would be very difficult/expensive to pull off.
For example, you would need test barrels finished with representative cartridges of varying length/width, each with test barrels finished at different tolerances/FB/throats, then you get into bullet ogives & length, load development to baselines, reload sizing systems for various amount of separated body runout to neck only to bullet seated only runouts and headspacings and pin striking.
All this before any notions across the gamut could hold as credible.
You can load perfect ammo and then put it in a large sloppy oversize chamber and bore and the perfection of the ammo may do nothing for you because of the poor quality of the chamber.
What I have noticed is that if you get the bullet loaded straight and the length of the sized case matches the chamber length exactly your ammo will shoot much better- even in old military rifles.
What I have noticed is that if you get the bullet loaded straight and the length of the sized case matches the chamber length exactly your ammo will shoot much better- even in old military rifles.
T-Rex,
Since few of us have the means to do real scientific tests we do the best that we can with what we have, and over time if our accuracy improves, perhaps we have made some observations and changes that are valid. I have a good friend that has an engineering background that tends to go off onto discourses abut what is needed to do proper testing. Of course he has never done any to that standard. From time to time I have helped him improve his results with some of what I have picked up unscientifically, by repeated trial and error. There is a part of the shooting sports that is known as short range benchrest. Perhaps you are familiar with it. I would venture that none of the advances that it has produced in the last sixty years or so have come through true scientific research.
Boyd
Since few of us have the means to do real scientific tests we do the best that we can with what we have, and over time if our accuracy improves, perhaps we have made some observations and changes that are valid. I have a good friend that has an engineering background that tends to go off onto discourses abut what is needed to do proper testing. Of course he has never done any to that standard. From time to time I have helped him improve his results with some of what I have picked up unscientifically, by repeated trial and error. There is a part of the shooting sports that is known as short range benchrest. Perhaps you are familiar with it. I would venture that none of the advances that it has produced in the last sixty years or so have come through true scientific research.
Boyd
Back in the day when I first started shooting (short range group and score). I was at a match in Mainville, Pa. and listened to Allie and Lee Euber holding court on the finer points of shooting small. Being a Newbie with limited funds, I took advantage of all the free wisdom from guys that I thought were the smartest guys on the planet. Well after going home and tweaking this and moving that I proceeded to get beat buy everybody except Stevie Wonder and that's only because he wasn't in attendance. I soon figured out that they weren't the smartest guys on the planet but I might be the dumbest guy on earth. Since then I follow my dear departed Dad's advice, don't believe anything you hear and only half of what you see. Sorry to side track the OP's post but as far as runout goes, all I can tell you is that my R.O. gauge hasn't been used in years.
I can be pretty certain that concentricity has nothing to do with my reasons for drinking. I shoot SAAMI chambers and no longer even own a concentricity gauge. I am guessing that the former condition negates the need for the second condition. Could be wrong, but probably will also have a lot of company there.
Life's too short...
Greg
Life's too short...
Greg
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