4runnerman
New member
I have ( For Me) found no better powder than RL-15 for the 308.
308 Target load
- Thread starter cw308
- Start date
RL-15's in close company with several powders with an excellent track record for accuracy in .308 Win cases. Check out the following and note those extruded powders between 88 and 101 are popular for bullet weights from 150 to 190 grains.
http://www.hodgdon.com/burn-rate.html
Further down there's IMR4350 at number 114; excellent with 200-gr. and heavier bullets in the .308 cases.
http://www.hodgdon.com/burn-rate.html
Further down there's IMR4350 at number 114; excellent with 200-gr. and heavier bullets in the .308 cases.
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I have also used RL-15 shot well, IMR 4064 works alittle better for me. The barrel is a match grade Rock Creek M24 5R 11.27 twist 21" brl with a break, I'll be using 4 different targets. I kind of felt it is a small load change, from 40.2 -.5 I should see some kind of group change.
That's a .3 grain change; right?
That's the charge weight spread good lots of commercial match ammo has. I think you'll need to shoot 40 to 50 shot groups to see a significant difference. Shoot two 5-shot groups with each load. If both charge weight's groups are not within 10% in size, neither one is a good representation on the charge weights accuracy. You'll need more shots per load to make a valid comparison.
That's the charge weight spread good lots of commercial match ammo has. I think you'll need to shoot 40 to 50 shot groups to see a significant difference. Shoot two 5-shot groups with each load. If both charge weight's groups are not within 10% in size, neither one is a good representation on the charge weights accuracy. You'll need more shots per load to make a valid comparison.
I've never ever looked for a one-hole group. That's a waste of my time. Such things only show up when one of two series of shooting stuff happens. One is when all the variables in rifle, ammunition, shooter and environment cancel each other out for every shot fired. The other is when all those variables are at zero. Which means, if you shoot enough shots with any rifle or ammo, one of the groups will be a one-holer; they're all capable of doing that. At least once.
How do you determine which one it was?
The largest groups shot with a given system (rifle + ammo + shooter) happen when all those variables add up. That tells you their cumulative amounts are large. So reduce them by doing the right things with the right stuff. Next time the largest group shot will be smaller. Do those things better and that biggest group's gonna be even smaller the next time.
Getting the average of several groups is almost as bad. Several few-shot groups' all-shots composite will, 99.9% of the time, be larger than the biggest few-shot group. And one series average could be smaller than another ones, but have the largest few shot groupo. As could the series having the biggest average have the smallest few-shot group.
Arsenals typically use mean radius of dozens of shots in a group testing rifle ammo. That shows the average distance a shot will go from group center. But the furthest shot is oft times 3 times as far away. A 300-shot group can have a mean radius at 600 yards of 3 inches. The average 10-shot group's about 6 inches The extreme spread of the group is 15 inches. But its got several few-shot groups well under 1 inch.
Go figure. . . . . . . Then use the method that gives the results you want.
Meanwhile shoot that 40.2 grain load several dozen times. One of the groups will be a tiny one-holer. The odds are in favor of that. So is the statistical probability.
How do you determine which one it was?
The largest groups shot with a given system (rifle + ammo + shooter) happen when all those variables add up. That tells you their cumulative amounts are large. So reduce them by doing the right things with the right stuff. Next time the largest group shot will be smaller. Do those things better and that biggest group's gonna be even smaller the next time.
Getting the average of several groups is almost as bad. Several few-shot groups' all-shots composite will, 99.9% of the time, be larger than the biggest few-shot group. And one series average could be smaller than another ones, but have the largest few shot groupo. As could the series having the biggest average have the smallest few-shot group.
Arsenals typically use mean radius of dozens of shots in a group testing rifle ammo. That shows the average distance a shot will go from group center. But the furthest shot is oft times 3 times as far away. A 300-shot group can have a mean radius at 600 yards of 3 inches. The average 10-shot group's about 6 inches The extreme spread of the group is 15 inches. But its got several few-shot groups well under 1 inch.
Go figure. . . . . . . Then use the method that gives the results you want.
Meanwhile shoot that 40.2 grain load several dozen times. One of the groups will be a tiny one-holer. The odds are in favor of that. So is the statistical probability.
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Bart,
What you are describing is a textbook example of process control and elimination/reduction of errors to improve accuracy. Unfortunately for us humans, there are so many variables, we cannot account for all the effects produced.
It is fascinating to try though. . .goodness knows I have tried.
What you are describing is a textbook example of process control and elimination/reduction of errors to improve accuracy. Unfortunately for us humans, there are so many variables, we cannot account for all the effects produced.
It is fascinating to try though. . .goodness knows I have tried.
There's only three variables and they're all about the bullet; muzzle velocity, ballistic coefficient and direction out the muzzle. At least in my opinion. Each one has several things contributing to it, but those are the three things that determine where the bullet lands. Stable atmospheric conditions assumed.
I know I can't correct for all those variables' contributing things but most of them can be minimized. That's why I never worked up any super accurate load for all the 30 caliber barrels I've wore out. I just used the same loads the winners and record setters used in the same barrels that worked well for them. My rifles tested as accurate as theirs did with those loads but I sometimes couldn't shoot 'me quite as straight as they did. And there's not much difference across them.
Two exceptions; each for new bullet types/weights there was no data for.
I know I can't correct for all those variables' contributing things but most of them can be minimized. That's why I never worked up any super accurate load for all the 30 caliber barrels I've wore out. I just used the same loads the winners and record setters used in the same barrels that worked well for them. My rifles tested as accurate as theirs did with those loads but I sometimes couldn't shoot 'me quite as straight as they did. And there's not much difference across them.
Two exceptions; each for new bullet types/weights there was no data for.
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Bart,
I would not agree there are but three variables. I think there are a multitude of variables and all have some effect on overall accuracy. What is not known is how much those variables contribute to the process or how to minimize their influence. There is a lot going on when you shoot a rifle. I try to minimize the effects of things I can control and tweak them to try to achieve that elusive one hole group. Alas, I still get frequent flyers. I presented a paper once at a Measurement Science conference and one of the presenters was talking about the myth of the random error. In statistics as related to process control, we often chart "things." When things deviate from nominal or spike from the +/- 3 Sigma limits, we attribute that to an "outlier." As the presenter was explaining he asked the audience if they had ever experienced the deadly "blue screen" of death on a computer. Naturally we all had. He then asked us if we considered that a "random" event. We all did. Then he posed the question that made us all really think. He said: "How many of you think that if exactly the same conditions exist again that caused your deadly blue screen were to exist again, would you again get the deadly blue screen?" We had to say yes. He opined that many of the things we attribute as random events are not random at all. They are the result of underlying physics that are not always well understood. We have used the term of "outliers" or "flyers" to describe the result of variables acting in concert to disrupt our one shot group. Sometimes the variables act to screw up our group and sometimes they act to enhance our groups. The problem for us shooters is to try to figure out what is what and trying to control the influence of any variable on the process.
That is why I said I do not agree there are 3 variables in play here. I just don't know how to accurately define them and reduce their influence. I measured things for a living for over 40 years and it was ALWAYS a struggle to totally eliminate the effects of variables from our results. The fact that we were deputized from the National Bureau of Standards to perform sub-micron level measurements meant we were doing a lot of things right.
Very interesting work and one of the things I carry over into my shooting is attention to detail.
I hope I have not bored you to tears, it is not my attention. I really look forward to your posts.
I would not agree there are but three variables. I think there are a multitude of variables and all have some effect on overall accuracy. What is not known is how much those variables contribute to the process or how to minimize their influence. There is a lot going on when you shoot a rifle. I try to minimize the effects of things I can control and tweak them to try to achieve that elusive one hole group. Alas, I still get frequent flyers. I presented a paper once at a Measurement Science conference and one of the presenters was talking about the myth of the random error. In statistics as related to process control, we often chart "things." When things deviate from nominal or spike from the +/- 3 Sigma limits, we attribute that to an "outlier." As the presenter was explaining he asked the audience if they had ever experienced the deadly "blue screen" of death on a computer. Naturally we all had. He then asked us if we considered that a "random" event. We all did. Then he posed the question that made us all really think. He said: "How many of you think that if exactly the same conditions exist again that caused your deadly blue screen were to exist again, would you again get the deadly blue screen?" We had to say yes. He opined that many of the things we attribute as random events are not random at all. They are the result of underlying physics that are not always well understood. We have used the term of "outliers" or "flyers" to describe the result of variables acting in concert to disrupt our one shot group. Sometimes the variables act to screw up our group and sometimes they act to enhance our groups. The problem for us shooters is to try to figure out what is what and trying to control the influence of any variable on the process.
That is why I said I do not agree there are 3 variables in play here. I just don't know how to accurately define them and reduce their influence. I measured things for a living for over 40 years and it was ALWAYS a struggle to totally eliminate the effects of variables from our results. The fact that we were deputized from the National Bureau of Standards to perform sub-micron level measurements meant we were doing a lot of things right.
Very interesting work and one of the things I carry over into my shooting is attention to detail.
I hope I have not bored you to tears, it is not my attention. I really look forward to your posts.
Each of those variables are influenced by several sub-variables. Those three I came up with are properties of the bullet that determine the path it takes, in my opinion. They're the lowest common denomators of all things measurable I can think of that puts a bullet in flight.
They're listed in:
http://thefiringline.com/forums/showthread.php?p=5843979#post5843979
They're listed in:
http://thefiringline.com/forums/showthread.php?p=5843979#post5843979
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