Node at different barrel lenght

[RTTY]

Hello, a friend myne had tested some Reload with a new powder.
This had find nodes at 38,7gn and 39,5gn.
My rifle and the rifle of this are identical apart for the barrel lenght, myne 28" and his 26".
Same bullets, same powder, same primers same case.
Have I some possibilities to find the nodes on my rifle near the friend nodes?

Thanks

 

[diggler1833]

The simple, yet frustrating answer:

- Maybe. Maybe not.

Barrels are individuals, so the guarantee that his load will be equally good in your barrel isn't there. However, certain cartridge/bullet/powder combinations seem to do well in many barrels.

You'll have to shoot it to see.

 

[RTTY]

So the solution is the usual one...
Try loads in 0.2gn increments near the best SD and ES rounds?

 

[Maurygold]

I’d be more concerned over length than charge based on my experience

 

[RTTY]

I’d be more concerned over length than charge based on my experience

Can you explain me better?

 

[Maurygold]

In my experience the cartridge length impacts group size more than charge. The old adage is that powder changes vertical and length changes horizontal

 

[RTTY]

My approach for load finding are to start 2 or 2,5gn below the max load data for the combos.
After finding a good load make some seathing adjustments.

 

[Seymour Fish]

Hello, a friend myne had tested some Reload with a new powder.
This had find nodes at 38,7gn and 39,5gn.
My rifle and the rifle of this are identical apart for the barrel lenght, myne 28" and his 26".
Same bullets, same powder, same primers same case.
Have I some possibilities to find the nodes on my rifle near the friend nodes?

Thanks

Yes. Reverse-engineer the load via GRT or quick load to derive barrel time for 26”. Some adjustment to Ba to match chrono #’s if needed. See where the barrel time falls on Chris Long’s model. See what percentage variation is vs Longs predicted ideal- generally 1-2% slower than predicted ie longer barrel time. Apply same %to 28” barrel time node prediction, adjusting charge as necessary to hit the desired #. Should be very close.

 

[RTTY]

Yes. Reverse-engineer the load via GRT or quick load to derive barrel time for 26”. Some adjustment to Ba to match chrono #’s if needed. See where the barrel time falls on Chris Long’s model. See what percentage variation is vs Longs predicted ideal- generally 1-2% slower than predicted ie longer barrel time. Apply same %to 28” barrel time node prediction, adjusting charge as necessary to hit the desired #. Should be very close.

Hi, thanks for the reply, but what you explained is still too elaborate for my skills. Can you help me?

 

[straightshooter1]

Hello, a friend myne had tested some Reload with a new powder.
This had find nodes at 38,7gn and 39,5gn.
My rifle and the rifle of this are identical apart for the barrel lenght, myne 28" and his 26".
Same bullets, same powder, same primers same case.
Have I some possibilities to find the nodes on my rifle near the friend nodes?

Thanks

Hi, thanks for the reply, but what you explained is still too elaborate for my skills. Can you help me?

To start with, two barrels of the same length, same material, same contour from the same company can still have chambers that are cut a little different even with the same reamer (reamers wear over time), which can produce different results. Even the bore can have a little different cut. Next, barrel lengths produces different velocities. . .the projectiles are in the bore for a different length of time with exactly the same cartridge load. Then there's "harmonics" where different barrel lengths vibrate differently, just like orchestral chimes. Different vibrations of the barrel means a different point of release when the projectile exits the muzzle.

You might use your friends load as a starting point for your load development. You might get lucky and find a "node" pretty close to what's works for him.

 

[JR1200W3]

Hello, a friend myne had tested some Reload with a new powder.
This had find nodes at 38,7gn and 39,5gn.
My rifle and the rifle of this are identical apart for the barrel lenght, myne 28" and his 26".
Same bullets, same powder, same primers same case.
Have I some possibilities to find the nodes on my rifle near the friend nodes?

Thanks

What's a node?

 

[JR1200W3]

Nevermind, I found the answer. Sounds like a "node" is a really small sample size that falls inside a larger distribution and causes shooters to think they have achieved something significant until it doesn't repeat which requires more testing. Usually, it seems, by round robin testing marking bullet tips with different colored permanent markers to track elevational impacts of single rounds as evidence of a singular data point, and to be interpreted as meaningful.

 

[Seymour Fish]

Hi, thanks for the reply, but what you explained is still too elaborate for my skills. Can you help me?

Start at low end of powder range. Load a one-shot ladder from there, in 0.3 gr increments. Hold same poi for each. Find your own node

 

[straightshooter1]

What's a node?

A "node" is technically a reference to the barrel's harmonics where there's the least movement at the muzzle and the projectile leaves the muzzle at the same position/angle resulting in more consistent POI's. Often it's nothing more than just a reference to where POI's stay consistent as conditions change (e.g. ambient and barrel temperature, throat erosion) and/or the slight variations in powder weight.

 

[JR1200W3]

A "node" is technically a reference to the barrel's harmonics where there's the least movement at the muzzle and the projectile leaves the muzzle at the same position/angle resulting in more consistent POI's. Often it's nothing more than just a reference to where POI's stay consistent as conditions change (e.g. ambient and barrel temperature, throat erosion) and/or the slight variations in powder weight.

Oh. I guess the council of 15yr ago reloading scientologists gathered a quorum and came to a consensus about which myth to apply to the name recently. Good to know. If you believe in that stuff

 

[30cal user]

develop a system and only change one thing at a time and do the same thing for each barrel and adjust the system when needed and keep notes and then verify the results next time, tunning takes time