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russell m
Guest
Is my assumption correct if I have vertical to change the powder charge. If my groups open up change seating depth. russell m
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murphy
Guest
Getting Into the Accuracy Window.
For what it is worth, here is how I think the whole accuracy node thing works. A rifle barrel vibrates mostly in the vertical plane in a slightly figure of 8 pattern. If your powder charge and bullet combination just happens to exit the muzzle at the top or bottom of the barrels amplitude ,the barrel is in the slow down or stop phase before starting to travel in the opposite direction and good accuracy results.
This spot at the end of the barrels elastic limit is the so called accuracy window and it may be accessed in many different ways. The Browning Boss or various barrel tuners is one way,incremental powder charges is another but the one that works best for me is simply to make big incremental changes to seating depth. With most rifles about four moves will get me onto the accuracy node. With factory produced sporter weight rifles the results have been spectular.With target rifles the results are harder to prove as the nodes appear to be very close together probably due to very stiff barrels being less susceptible to vibration. Hope this helps as without uderstanding the nature of the beast, making adjustments is difficult. Reguards Murphy
For what it is worth, here is how I think the whole accuracy node thing works. A rifle barrel vibrates mostly in the vertical plane in a slightly figure of 8 pattern. If your powder charge and bullet combination just happens to exit the muzzle at the top or bottom of the barrels amplitude ,the barrel is in the slow down or stop phase before starting to travel in the opposite direction and good accuracy results.
This spot at the end of the barrels elastic limit is the so called accuracy window and it may be accessed in many different ways. The Browning Boss or various barrel tuners is one way,incremental powder charges is another but the one that works best for me is simply to make big incremental changes to seating depth. With most rifles about four moves will get me onto the accuracy node. With factory produced sporter weight rifles the results have been spectular.With target rifles the results are harder to prove as the nodes appear to be very close together probably due to very stiff barrels being less susceptible to vibration. Hope this helps as without uderstanding the nature of the beast, making adjustments is difficult. Reguards Murphy
M
murphy
Guest
Getting Into the Accuracy Window.
For what it is worth, here is how I think the whole accuracy node thing works. A rifle barrel vibrates mostly in the vertical plane in a slightly figure of 8 pattern. If your powder charge and bullet combination just happens to exit the muzzle at the top or bottom of the barrels amplitude ,the barrel is in the slow down or stop phase before starting to travel in the opposite direction and good accuracy results. This spot at the end of the barrels elastic limit is the so called accuracy window and it may be accessed in many different ways. The Browning Boss or various barrel tuners is one way,incremental powder charges is another but the one that works best for me is simply to make big incremental changes to seating depth. With most rifles about four moves will get me onto the accuracy node. With factory produced sporter weight rifles the results have been spectular.With target rifles the results are harder to prove as the nodes appear to be very close together probably due to stiff barrels being less susceptible to vibration. Hope this helps as without uderstanding the nature of the beast, making adjustments is difficult. Reguards Murphy.
For what it is worth, here is how I think the whole accuracy node thing works. A rifle barrel vibrates mostly in the vertical plane in a slightly figure of 8 pattern. If your powder charge and bullet combination just happens to exit the muzzle at the top or bottom of the barrels amplitude ,the barrel is in the slow down or stop phase before starting to travel in the opposite direction and good accuracy results.
This spot at the end of the barrels elastic limit is the so called accuracy window and it may be accessed in many different ways. The Browning Boss or various barrel tuners is one way,incremental powder charges is another but the one that works best for me is simply to make big incremental changes to seating depth. With most rifles about four moves will get me onto the accuracy node. With factory produced sporter weight rifles the results have been spectular.With target rifles the results are harder to prove as the nodes appear to be very close together probably due to stiff barrels being less susceptible to vibration. Hope this helps as without uderstanding the nature of the beast, making adjustments is difficult. Reguards Murphy.
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Pete in Surry
Guest
I have experienced the same
I select a powder charge that proiduces good speed with good crono numbers and then tune it in using seating depth. I use .003 as my incremental change and I too usually find a round hole within the first 5 increments. There is sometimes the odd barrel that will like a .015 jam but usually the hole comes in the first .009. I have wondered about but never felt I had to adjust powder a bit after finding the single hole, to make it smaller. Logically one would think that would be the thing to do.
For those who don't think precise seating depths and exact OAL's, measured where the bullet will engage the lands matters, this process will show one very quickly.
I select a powder charge that proiduces good speed with good crono numbers and then tune it in using seating depth. I use .003 as my incremental change and I too usually find a round hole within the first 5 increments. There is sometimes the odd barrel that will like a .015 jam but usually the hole comes in the first .009. I have wondered about but never felt I had to adjust powder a bit after finding the single hole, to make it smaller. Logically one would think that would be the thing to do.
For those who don't think precise seating depths and exact OAL's, measured where the bullet will engage the lands matters, this process will show one very quickly.
Pete....I do a lot of the same but I start at jam, find as fast (hot) as load that will shoot decent and then tweak by moving the seating depth in .005 at a time, then in smaller increments to fine tune. I like to keep the bullet as close to jam as possible to remove variables.
Hovis
Hovis
M
murphy
Guest
On seating depth.
This seating depth thing is amazing. Benchrest rifles seem to respond to increments of .005" because of their stiff barrels and tight tolerances.What most people don't seem to realise is that it is just as easy to tune a rifle with a number 3 profile barrel this way ,except that the seating depth increments need to be much more course because of the greater barrel amplitude. My experiments lead me to believe that about 1/16" is right for a sporter. The degree of seating depth movement is proportional to the degree of refinement built into your rifle.
This seating depth thing is amazing. Benchrest rifles seem to respond to increments of .005" because of their stiff barrels and tight tolerances.What most people don't seem to realise is that it is just as easy to tune a rifle with a number 3 profile barrel this way ,except that the seating depth increments need to be much more course because of the greater barrel amplitude. My experiments lead me to believe that about 1/16" is right for a sporter. The degree of seating depth movement is proportional to the degree of refinement built into your rifle.