sort of a newby to reloading, been reading a lot on here and have been working on load developement mainly ocw. i keep wondering if all these ladder and ocw tests are doing is telling me that this rifle likes this velocity for this bullet. and if so does that mean that any powder i use under that bullet is gonna shoot best at that velocity. it seems to me that barrel harmonics would be directly tied to velocity and thats whats changing at different charge weights. am i misguided or oversimplifying this? please school me.
newby ocw question
- Thread starter marduk185
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Re: newby ocw question
I think the harmonics of the barrel is more a direct result of the chamber pressure and not speed of the round exiting the muzzle. Different powders will develop pressures at different rates and therefore change the harmonics.
I think the harmonics of the barrel is more a direct result of the chamber pressure and not speed of the round exiting the muzzle. Different powders will develop pressures at different rates and therefore change the harmonics.
Re: newby ocw question
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: marduk185</div><div class="ubbcode-body">and if so does that mean that any powder i use under that bullet is gonna shoot best at that velocity.</div></div>
To a first order, yes--when you get to finely tuned loads, this general trend falls apart unless the pressure curves by the different powders have almost the excat shame shapes.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> it seems to me that barrel harmonics would be directly tied to velocity and thats whats changing at different charge weights. </div></div>
To a first order this is the general trend. It will fail to work when using powders that are on opposite ends of the burn rate curves that are still appropriate for the cartrige in question.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: marduk185</div><div class="ubbcode-body">and if so does that mean that any powder i use under that bullet is gonna shoot best at that velocity.</div></div>
To a first order, yes--when you get to finely tuned loads, this general trend falls apart unless the pressure curves by the different powders have almost the excat shame shapes.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> it seems to me that barrel harmonics would be directly tied to velocity and thats whats changing at different charge weights. </div></div>
To a first order this is the general trend. It will fail to work when using powders that are on opposite ends of the burn rate curves that are still appropriate for the cartrige in question.
Re: newby ocw question
so if they are similar burn rates my assumption may work. like going varget to imr4064 to h4895 for .308 loads perhaps?
so if they are similar burn rates my assumption may work. like going varget to imr4064 to h4895 for .308 loads perhaps?
Re: newby ocw question
Maybe possibly. Remember, though, that some powders with very similar bulk burn 'rates' can have very different specific burn characteristics. Double-base spherical powders come to mind as ones which will have a noticeably slower barrel time for a given velocity vs. single-base extruded powders. There are even quite noticeable differences between brands of similar sphericals. My limited experience (I tend to shoot ball/spherical powder, so don't have too much experience with most extruded powders) is that this kind of difference is easily enough to mess up the notion of an OCW being tied to a muzzle velocity.
Maybe possibly. Remember, though, that some powders with very similar bulk burn 'rates' can have very different specific burn characteristics. Double-base spherical powders come to mind as ones which will have a noticeably slower barrel time for a given velocity vs. single-base extruded powders. There are even quite noticeable differences between brands of similar sphericals. My limited experience (I tend to shoot ball/spherical powder, so don't have too much experience with most extruded powders) is that this kind of difference is easily enough to mess up the notion of an OCW being tied to a muzzle velocity.
Re: newby ocw question
this theory also came into play for me when switching brass makes. from prvi to lake city powder charge varied to reach same speeds but with pretty similar results for where the node was, however reaches pressure spike earlier with prvi than with lc. co-enky-dink?
this theory also came into play for me when switching brass makes. from prvi to lake city powder charge varied to reach same speeds but with pretty similar results for where the node was, however reaches pressure spike earlier with prvi than with lc. co-enky-dink?
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