Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Help me understand this-Velocity is going down??
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="QuietTexan" data-source="post: 2485167" data-attributes="member: 116181"><p>Short answer - yes, velocity can and will decrease at certain points with an increased charge weight.</p><p></p><p></p><p>You asked for a long answer <img class="smilie smilie--emoji" loading="lazy" alt="😎" title="Smiling face with sunglasses :sunglasses:" src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f60e.png" data-shortname=":sunglasses:" /> Probably a confluence of too many things to ever nail down a solid "why". Change in the timing of the gas going around the bullet before engraving, changes in internal ballistics due to being at a different point for pressure/burn rate, change in how the primer ignites the column, bullet seating change from being pushed out, inconsistent powder packing if you aren't using a drop tube. So many things it could be.</p><p></p><p><s>Not sure how many shots you took at each charge weight</s>, My man! 6 shots at each weight is commendable, and actually gets to the edge of being inferential. No less than 5 shots for numbers is my general opinion, but as many as possible is best. There's a mathematical answer here that could be anything from "yes it's actually slower" to "it's not really slower, it's just a very unstable load and/or you don't have enough data points to show that it's really faster but you're so likely to get a slow load that you can't really use the load".</p><p></p><p>Typical results of a ladder test - are the decreases real? Or are they statistical lies where a 95% percentile round was shot right before a 5% percentile round?</p><p>[ATTACH=full]352773[/ATTACH]</p><p>Source:</p><p>[URL unfurl="true"]https://precisionrifleblog.com/2012/07/13/creighton-audette-ladder-testing/[/URL]</p><p></p><p>In practical terms we avoid the messy areas and focus on the more promising flat areas because it's more likely they actually are stable than it is that the unstable areas are actually stable. Not a lot of hard evidence on what makes bad things bad because not a lot of people are lining up to make bad loads on purpose. I do it sometimes - if I find a bad load I'll keep it written down to use to test something specific or see if it can get one part of it tuned better, but generally I work from good to better. Mikecr makes a good point in that testing the effects of some changes needs to be done intentionally outside of a node so that the changes aren't being obscured by another factor compensating for those changes. Maybe we should do more "bad" work to learn from it.</p><p></p><p>Edit: You posted while I was typing, had to change my assumptions.</p></blockquote><p></p>
[QUOTE="QuietTexan, post: 2485167, member: 116181"] Short answer - yes, velocity can and will decrease at certain points with an increased charge weight. You asked for a long answer 😎 Probably a confluence of too many things to ever nail down a solid "why". Change in the timing of the gas going around the bullet before engraving, changes in internal ballistics due to being at a different point for pressure/burn rate, change in how the primer ignites the column, bullet seating change from being pushed out, inconsistent powder packing if you aren't using a drop tube. So many things it could be. [S]Not sure how many shots you took at each charge weight[/S], My man! 6 shots at each weight is commendable, and actually gets to the edge of being inferential. No less than 5 shots for numbers is my general opinion, but as many as possible is best. There's a mathematical answer here that could be anything from "yes it's actually slower" to "it's not really slower, it's just a very unstable load and/or you don't have enough data points to show that it's really faster but you're so likely to get a slow load that you can't really use the load". Typical results of a ladder test - are the decreases real? Or are they statistical lies where a 95% percentile round was shot right before a 5% percentile round? [ATTACH type="full" width="367px" alt="1648138049861.png"]352773[/ATTACH] Source: [URL unfurl="true"]https://precisionrifleblog.com/2012/07/13/creighton-audette-ladder-testing/[/URL] In practical terms we avoid the messy areas and focus on the more promising flat areas because it's more likely they actually are stable than it is that the unstable areas are actually stable. Not a lot of hard evidence on what makes bad things bad because not a lot of people are lining up to make bad loads on purpose. I do it sometimes - if I find a bad load I'll keep it written down to use to test something specific or see if it can get one part of it tuned better, but generally I work from good to better. Mikecr makes a good point in that testing the effects of some changes needs to be done intentionally outside of a node so that the changes aren't being obscured by another factor compensating for those changes. Maybe we should do more "bad" work to learn from it. Edit: You posted while I was typing, had to change my assumptions. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Help me understand this-Velocity is going down??
Top