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
7mm STW
How far do you have to jump the lands?
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="Greyfox" data-source="post: 2603576" data-attributes="member: 10291"><p>I agree with this. </p><p>Whether VLD or more conventionally shaped bullets I have frequently found there to be more then one accuracy node with bullet jump. I have precision rifles that use jumps from .005" to +.150". Given I find a bullet that will deliver consistent accuracy at more then one distance, my preference is to choose the greater distance. My observation have been that while velocity can be a lower, so will chamber pressure, throat erosion, and the necessity of "chasing the lands" in order to maintain accuracy with a very small jump. A .005" throat erosion with a .005" jump doubles the distance and may throw you out of the node. With a longer jump, IMO, throat erosion is lessened, and at the same time, if any erosion does occur, it's effect on the longer distance jump is far less influential on the accuracy node. A .005" throat erosion effect on a .075" jump is only 7% compared to 100% in the previous example, and, rarely takes you out if the accuracy node which tend to be much wider when a longer jump is used. Of course, all this is just my experience and speculation with my rifles/loads, and, dependent on being able to achieve your desired accuracy in a longer node. It is also important, as noted by Bill Larson that there is minimal run-out(<.003"). I have run a few 6.5x284's over the years that I have observed bullet jump effects. My rifles that run mostly VLD style bullets at jumps in excess of .050" have demonstrated less throat wear with minimal/no load tuning for +1000 rounds compared to my <.020" loads requiring more attention/ load tuning over shot volume.</p></blockquote><p></p>
[QUOTE="Greyfox, post: 2603576, member: 10291"] I agree with this. Whether VLD or more conventionally shaped bullets I have frequently found there to be more then one accuracy node with bullet jump. I have precision rifles that use jumps from .005” to +.150”. Given I find a bullet that will deliver consistent accuracy at more then one distance, my preference is to choose the greater distance. My observation have been that while velocity can be a lower, so will chamber pressure, throat erosion, and the necessity of “chasing the lands” in order to maintain accuracy with a very small jump. A .005” throat erosion with a .005” jump doubles the distance and may throw you out of the node. With a longer jump, IMO, throat erosion is lessened, and at the same time, if any erosion does occur, it’s effect on the longer distance jump is far less influential on the accuracy node. A .005” throat erosion effect on a .075” jump is only 7% compared to 100% in the previous example, and, rarely takes you out if the accuracy node which tend to be much wider when a longer jump is used. Of course, all this is just my experience and speculation with my rifles/loads, and, dependent on being able to achieve your desired accuracy in a longer node. It is also important, as noted by Bill Larson that there is minimal run-out(<.003”). I have run a few 6.5x284’s over the years that I have observed bullet jump effects. My rifles that run mostly VLD style bullets at jumps in excess of .050” have demonstrated less throat wear with minimal/no load tuning for +1000 rounds compared to my <.020” loads requiring more attention/ load tuning over shot volume. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
7mm STW
How far do you have to jump the lands?
Top