been reloading for years but, new to precision loads. my question is this. is velocity accuracy? i have seen a wide range of max velocities for .308. will a slower bullet be more accurate at 300 yards and fall to the ground at 1000? i would like to work up 1 load that works out to 1000 with 175 smk's. is that possible. do i just play around till i bump into a load that works all over or is there a process that helps work up to a best load for this barrel?
Re: load work up
Search on <span style="font-style: italic">Optimal Charge Weight</span> and <span style="font-style: italic">Audette's Ladder Method</span>.
Ballistics Tables will answer your questions regarding how different bullets perform at various ranges.
Search on <span style="font-style: italic">Optimal Charge Weight</span> and <span style="font-style: italic">Audette's Ladder Method</span>.
Ballistics Tables will answer your questions regarding how different bullets perform at various ranges.
Re: load work up
There is a methodology to developing a load which will locate the nodes, and a range of loads which have a common point of impact POI in only 15 to 20 rounds, then how to tune selected load by adjusting seating depth. You have a real opportunity to adopt a mythology that will help you developed loads very rapidly with only a few test rounds.
These two links will give you the information the first is the methodology the second is a web forum were people discuss their loads and post photos. There is a learning curve in selecting the optimum charge weight from your test, look at some test does not matter which powder or even cal. just to get the hang of it.
www.optimalchargeweight.embarqspace.com/ and www.practicalrifler.6.forumer.com/index.php
www.eskimo.com/~jbm/calculations/traj/traj.html free calculator
There is a methodology to developing a load which will locate the nodes, and a range of loads which have a common point of impact POI in only 15 to 20 rounds, then how to tune selected load by adjusting seating depth. You have a real opportunity to adopt a mythology that will help you developed loads very rapidly with only a few test rounds.
These two links will give you the information the first is the methodology the second is a web forum were people discuss their loads and post photos. There is a learning curve in selecting the optimum charge weight from your test, look at some test does not matter which powder or even cal. just to get the hang of it.
www.optimalchargeweight.embarqspace.com/ and www.practicalrifler.6.forumer.com/index.php
www.eskimo.com/~jbm/calculations/traj/traj.html free calculator
Re: load work up
Accuracy and velocity are only vaguely related.
While it's true that the faster round will drop and drift less, actual basic dispersion is a factor of barrel harmonics and bore transit time.
A particular barrel will have one or more optimum bore transit times, each of which will correspond to a specific velocity, and different load combination recipes will generate identical velocities, but different bore transit times.
It's the transit times that correlate to barrel harmonics, and that's what counts, not the same velocity.
While it's true that loads near max will often show good accuracy, this is a lot more of a coincidence than a rule of thumb. Even when they do, the value of this accuracy is dubious, as such loads tend to degrade barrel performance far more quickly, rendering the accuracy more short-lived.
When a barrel produces more than one accuracy load, usually the slower one is preferable, because of enhanced bore life issues.
Greg
Accuracy and velocity are only vaguely related.
While it's true that the faster round will drop and drift less, actual basic dispersion is a factor of barrel harmonics and bore transit time.
A particular barrel will have one or more optimum bore transit times, each of which will correspond to a specific velocity, and different load combination recipes will generate identical velocities, but different bore transit times.
It's the transit times that correlate to barrel harmonics, and that's what counts, not the same velocity.
While it's true that loads near max will often show good accuracy, this is a lot more of a coincidence than a rule of thumb. Even when they do, the value of this accuracy is dubious, as such loads tend to degrade barrel performance far more quickly, rendering the accuracy more short-lived.
When a barrel produces more than one accuracy load, usually the slower one is preferable, because of enhanced bore life issues.
Greg
Re: load work up
in the reloading section up near the top their is the loads for 308 winchester---- hit that and search through it looking for similar components and similar rifle, similar barrel lenght and twist. After you find a few matches then start the load a bit lower than what they used and work up from there using OCW or ladder or both or whatever you like. Ultimately look for what your rifle likes and shoot it.
I have had speeds close as far as deviation and they wouldnt group as well as other groups with high speed deviations. a bullet needs to be spun just so with your twist and length- not just low deviations to be happy. With that in mind, you find what your rifle likes for speeds and then shrink your SD and you will be set up well.
in the reloading section up near the top their is the loads for 308 winchester---- hit that and search through it looking for similar components and similar rifle, similar barrel lenght and twist. After you find a few matches then start the load a bit lower than what they used and work up from there using OCW or ladder or both or whatever you like. Ultimately look for what your rifle likes and shoot it.
I have had speeds close as far as deviation and they wouldnt group as well as other groups with high speed deviations. a bullet needs to be spun just so with your twist and length- not just low deviations to be happy. With that in mind, you find what your rifle likes for speeds and then shrink your SD and you will be set up well.
Re: load work up
great advice, guys, i appreciate it. i have looked through the loads section and seen some close to me. we're talking such small differences making huge changes in poi, i'm glad to know there are processes to find the best for me. looks like i've got some reading to do. thanks again.
great advice, guys, i appreciate it. i have looked through the loads section and seen some close to me. we're talking such small differences making huge changes in poi, i'm glad to know there are processes to find the best for me. looks like i've got some reading to do. thanks again.
