Why are velocity nodes so important?

[jlanecr500]

Basically, the vibration or wave that is caused when the primer fires, travels back and forth from breech to muzzle. The barrel diameter at any given point is largest when the wave is there so we want the wave near the breech when the bullet exits the muzzle. So, with this wave traveling back and forth, the bullet might exit the muzzle on the 4th cycle of the wave for one node. But if we increase our charge which speeds up the bullet, the bullet could exit on the 3rd cycle of the wave on the next node. So, this explains what I meant when I said that I hit 3 different nodes with the same bullet and powder but with different charge weights. Beyond this, all we really need is the node list and Quick Load software, along with bullet/powder/barrel length/brass water weight in grains/desired powder to calculate loads that get us real close to the node and prepares us for ladder or OCW testing. Below is the barrel time list.

 

[jlanecr500]

Let's calculate some loads in Quickload. Someone pick a rifle that you have all reloading components for and you know has a good barrel. I will need specifics.
1 caliber
2 Bullet manufacturer, weight, description, and if possible part number.
3 using a comparator or other means, measure the COAL with the bullet seated .020" from the lands. ( We can go Sammi length but it will be a better starting load at .020" off lands)
4 Weigh a piece of fire formed, neck sized brass with primer installed. Then fill it with water and weigh again. I need the weight difference. That is the cartridge fill weight in h20.
5 measure barrel length from bolt face to end of muzzle. If threaded, to end of threads without brake or flash hider.
6 Pick your powder. Obviously it needs to be a powder that works well in that caliber.

 

[fullstream]

Jlanecr500 knows this stuff inside and out, he got me going with my WinMag and was within .5 gr of my powder charge that ended up being the accuracy node for my 180 gr NAB final load recipe.

Agreed he's a good fellow to ask questions too. He shares his knowledge freely. I for one am glad he's part of our forum.

 

[MUP]

I've got the specs from my Rem Sendero 300WinMag, but I only have the OAL to the tip recorded. I can get the data from my book when I get home tho.

 

[jlanecr500]

I've got the specs from my Rem Sendero 300WinMag, but I only have the OAL to the tip recorded. I can get the data from my book when I get home tho.

That's what I need, COAL to the bullet tip while seated .020" off the lands. I know it can vary a little with lead tipped bullets. Also, if your barrel is throated excessively deep, loading to .020" off the lands may exceed mag length. If you would like to stay mag length, we can just run it at that length.

 

[MUP]

Remington Model 700 Sendero 300 WM
Nosler 180 gr Accubond bullet
Empty case - 241.5 gr
Filled case - 333.7 gr
COAL - Case Base to tip = 3.575"
Barrel length - 26.063"

Powder RL22
Primer - CCI LRP

 

[jlanecr500]

I ran the load as requested with RL22. Quickload has a function that allows it to list alternative powder loads that meet certain criteria that you specify, such as barrel time, max pressure, cartridge fill %, etc. Of those loads, I picked the best and have them for your consideration also. These loads will require tuning to your gun but will likely be very close to the node. Usually within .5 gr. As with any new load, watch for pressure signs. ALSO, These loads are calculated for THIS rifle and cartridge COAL. A shorter COAL with the same load will equal increased pressure. Propellant type and charge in grains are in the lower window of each pic

 

[MUP]

This rifle and load recipe have already been dialed in, and, using RL 22, and the rest of the posted load data, the finished load for me worked at 75.5 gr of powder. That recipe netted a 3 shot group of .4 MOA at 1000 yds. Amazed at the accuracy of this program.

 

[Maude]

This is a very interesting read. Thanks for sharing this info. I've read the paper twice and follow what Chris is proposing. I want to use Quickload to see if I can verify some of my pet loads and possibly improve on them.

 

[TheLBLman]

That recipe netted a 3 shot group of .4 MOA at 1000 yds. Amazed at the accuracy of this program.

Seriously? 0.4 MOA at 1,000 yds?
Com' On Man! Are You Serious?

 

[jlanecr500]

This is a very interesting read. Thanks for sharing this info. I've read the paper twice and follow what Chris is proposing. I want to use Quickload to see if I can verify some of my pet loads and possibly improve on them.

The research Chris did adds meaning to it all. The barrel time chart is the meat of the equation. We must remember that the barrel time list was compiled using a 6BR caliber. Bullet travel distance in the barrel is a big part of the barrel time equation. A 6BR cartridge is much shorter than MUP's 300WM so it will have a longer travel distance vs the 300WM in a given length barrel. Therefore, I take the COAL difference between the 6BR and the caliber I'm calculating for and subtract it from the barrel length on the node list. For example, MUP's barrel is 26" but after subtracting the difference in COAL, I used the 25.5"barrel length on the node list to find correct barrel times. I continue to use the 26" barrel length in Quickload.

 

[MUP]

Seriously? 0.4 MOA at 1,000 yds?
Com' On Man! Are You Serious?

Yes sir, a 3 shot group, but still at .44 MOA.

 

[TheLBLman]

Yes sir, a 3 shot group, but still at .44 MOA.

That's very impressive
Best I've ever done with any gun has been 0.125 MOA at 200 yds (3-shot group),
but my MOA always GREATLY expands as the range increases.

If I can consistently get a 1" group (0.50 MOA) at 200 yds,
it "should" be about a 2" group (0.50 MOA) at 400 yds.

But, I'd typically be lucky for 0.50 moa (1" group) at 200
to (consistently) be any less than 1.50 moa (6" group) at 400.

Amazing how the variable factors get amplified as range increases.

 

[MUP]

Wind makes or breaks even a good load.

 

[MUP]

Well it was actually .41 MOA

 

[TheLBLman]

Amazing shooting, MUP!

 

[MUP]

With a calm wind I might could stay under MOA with any consistently. Reading the wind is what I'm trying learn at this point, as I have some good loads that I think will work for groups, just need to learn how to read wind speed for proper windage dialing now, hopefully.

 

[fairchaser]

With a calm wind I might could stay under MOA with any consistently. Reading the wind is what I'm trying learn at this point, as I have some good loads that I think will work for groups, just need to learn how to read wind speed for proper windage dialing now, hopefully.

 

[MUP]

Thanks fc! Looks like I know what my next book purchase is going to be now!