• Help Support TNDeer:

Why are velocity nodes so important?

fairchaser

fairchaser

Well-Known Member
Joined
Sep 13, 2011
Messages
9,095
Location
TN, USA
We have powder measures that will measure down to the kernel of powder. Yet, we obsess over velocity nodes. Shouldn't we more concerned about groups , SD's and ES?
 
Long range shooters I've been talking to have always told me that "numbers are nice" but "don't neglect what shows up on paper, bc groups win matches, not velocity". They know more than I do, so I keep tabs on my numbers, but will take a small group size over a velocity node. Hopefully, they're one and the same tho. ;) Which is the case with one of my 6.5 Creedmoor loads, single digit sd and es and sub MOA group size.
 
I know guys who move their powder charge due to changes in temp, pressure and even elevation. There are other factors affecting speed over powder charge and pressures. I believe we lump these together in a node because it's the easiest thing to measure.

I've done most of my testing at 100 yds but when I moved out to 600, I found some more tweaking had to be done. Groups at 100, 200 and even 300 might not translate to 600 due to barrel harmonics. Like MUP says, the proof is on paper. Groups win matches.
 
When referred to as velocity nodes, people get the wrong impression. What it all boils down to is barrel time. Obviously, the hotter the charge, more velocity is gained and it is possible to advance to the next node or barrel time. Generally, nodes are around a couple grains apart on say 308, 30-06, etc. A few years ago, I spent a lot of time, research, money learning about nodes, barrel time, barrel harmonics, etc, including pressure trace equipment and load development software. Being as I use it for smokeless muzzleloading, I am not limited to case capacity. There were no loads out there for advanced ignition 40 and 45 caliber sml's and without proper tools, things can get super dangerous in a hurry. So I built a 45 sml with a 1.385" straight barrel 28" long on a Savage large target action nutless like a Remington. I obtained, developed, and verified a calibration load for the pressure trace equipment. I also built a 40 cal similarly. When I built the 40, there were no really good bullets out there so Kyle Pittman, owner of Pittman Bullets designed a line of cup and core high bc 40cal bullets. When he got the first test bullets, he brought 12 of each weight of 225gr, 250gr, and 275gr to the Norris rifle range. I brought my new 40 cal sml with a Rock Creek 1:13.2 twist barrel at 28".
Being that we had never shot those bullet weights, much less those bullets, we were in the dark on loads. I had already spent a great deal of time with Quick Loads and barrel times that were already established through another developer. I ran loads with various powders, looking to obtain barrel times that matched established nodes, that were in a stable pressure range (45 to 65kpsi). The following pics are of targets on that test day. Mind you these are untuned loads. I took vials with these charges and that is all we had, along with12 bullets of each weight.

My spare time is valuable to me but I also like to pass on knowledge that I have acquired because it is super interesting to me. I am willing to do a series of threads over a period of time explaining this matter and giving links so that you can see for yourself, but I'm not going to take a beating on here over it. You guys can decide up front how it's gonna be and we will go from there. I do not proclaim to be a know-it-all, I just want to share information. Granted, with rifles, it is all pretty much figured out but I can show without a doubt how it works. Here are the targets. Remember, these are untuned loads calculated on the computer, measured and poured down the barrel with a bullet design that had never before been fired in any gun on the planet. Notice I hit 3 different nodes with the same bullet and powder just with different charges. The pics are out of order but it is easy to see the increased charges and velocities.
20170910_213335.jpg
20170910_213405.jpg
 

Attachments

  • 20170910_213310.jpg
    20170910_213310.jpg
    741.8 KB · Views: 57
Last edited:
jlanecr500 said:
When referred to as velocity nodes, people get the wrong impression. What it all boils down to is barrel time. Obviously, the hotter the charge, more velocity is gained and ot is possible to advance to the next node or barrel time. Generally, nodes are around a couple grains apart on say 308, 30-06, etc. A few years ago, I spent a lot of time, research, money learning about nodes, barrel time, barrel harmonics, etc, including pressure trace equipment and load development software. Being as I use it for smokeless muzzleloading, I am not limited to case capacity. There were no loads out there for advanced ignition 40 and 45 caliber sml's and without proper tools, things can get super dangerous in a hurry. So I built a 45 sml with a 1.385" straight barrel 28" long on a Savage large target action nutless like a Remington. I obtained, developed, and verified a calibration load for the pressure trace equipment. I also built a 40 cal similarly. When I built the 40, there were no really good bullets out there so Kyle Pittman, owner of Pittman Bullets designed a line of cup and core high bc 40cal bullets. When he got the first test bullets, he brought 12 of each weight of 225gr, 250gr, and 275gr to the Norris rifle range. I brought my new 40 cal sml with a Rock Creek 1:13.2 twist barrel at 28".
Being that we had never shot tose bullet weights, much less tose bullets, we were in the dark on loads. I had already spent a great deal of time with Quick Loads and barrel times that were already established through another developer. I ran loads with various powders, looking to obtain barrel times that matched established nodes, that were in a stable pressure range (45 to 65kpsi). The following pics are of targets on that test day. Mind you these are unturned loads. I took vials with these charges and that is all we had, along with12 bullets of each weight.

My spare time is valuable to me but I also like to pass on knowledge that I have acquired because it is super interesting to me. I am willing to do a series of threads over a period of time explaining this matter and giving links so that you can see for yourself, but I'm not going to take a beating on here over it. You guys can decide up front how it's gonna be and we will go from there. I do not proclaim to be a know-it-all, I just want to share information. Granted, with rifles, it is all pretty much figured out but I can show without a doubt how it works. Here are the targets. Remember, these are untuned loads calculated on the computer, measured and poured down the barrel with a bullet design that had never before been fired in any gun on the planet. Notice I hit 3 different nodes with the same bullet and powder just with different charges. View attachment 73307View attachment 73309
Click to expand...
That's some great shooting and looks like a great bullet/load for the sml. I'd love to pick your brain sometime. Share anything you want. I'm sure many of us reloaders would appreciate it. Btw, is there anything that Varget doesn't work well in? Lol
 
I don't have pics of the 250gr loads but here are some of the 225gr loads from that test day. Check out the lower target. Almost 3400fps with a 225gr bullet into a .210" 3 shot group. Not too shabby for a computer calculated load.
20180917_134148.jpg
20180111_121206.jpg
 
Excellent shooting for sure. Recoil? When I see 86 grains of IMR3031 behind a 225 grain bullet the recoil has to be rough (?).
 
DaveB said:
Excellent shooting for sure. Recoil? When I see 86 grains of IMR3031 behind a 225 grain bullet the recoil has to be rough (?).
Click to expand...
It's not that bad in a gun weighing 10 to 12 pounds fully dressed. Now, 140gr of H4350 behind a 350gr bullet at 3400fps will definitely get your attention, even in a 18 pound gun.
My hunting sml is a 22" barreled 40 cal weighing 11 pounds dressed shooting a 300gr bullet over 83 gr imr4166 is a little shy of a mossberg 835 with a 3 1/2" turkey load.
 
Last edited:
What do you mean when you say you "hit 3 different nodes"? I see 3 nice size groups at 3 different velocities. Do you have a lot of groups at other velocities with significantly larger groups? I'd think you would.

Also isn't this the purpose of the process some call a "Ladder test" I think where they shoot a series of shots loaded with different powder charges at a long range target and mark each bullet hole, then see the holes that tend to clump together as an indicator of a "Node" where small variations in powder make the least difference in velocity hence drop for long range??
 
Hunter 257W said:
What do you mean when you say you "hit 3 different nodes"? I see 3 nice size groups at 3 different velocities. Do you have a lot of groups at other velocities with significantly larger groups? I'd think you would.

Also isn't this the purpose of the process some call a "Ladder test" I think where they shoot a series of shots loaded with different powder charges at a long range target and mark each bullet hole, then see the holes that tend to clump together as an indicator of a "Node" where small variations in powder make the least difference in velocity hence drop for long range??
Click to expand...
Typically, I calculate close enough to the node so as to start out with a decent group. Sometimes things don't go as planned and some powders don't work out either because they foul heavily making loading more difficult, etc.

Some do ladder tests and others do OCW progressions. Either way, at .2gr increments, I would go thru a lot of $2 bullets spanning the gap from 74gr to 86gr of powder in a ladder or OCW test. Calculating the load in Quick Load and targeting specific barrel times, I am able to get within a grain or 2 of the sweet spot. Unlike common cartridges, that have book loads which only need tweaking in your gun, we are shooting loads that have never been fired before so we're in uncharted territory. I understand that this doesn't mean much to some people but in this case it is a vehicle to demonstrate proven concepts and theories. This in no way replaces shooting ladders or progressions but it will get you close and demonstrate why nodes are so important. I know it isn't real clear as I really haven't gotten in deep enough but I will. I found this target pic from that same test day. It is 250gr bullets but doesn't have charges listed. We didn't shoot any large groups that day as I was able to calculate close to the nodes. Notice the velocities that are similar to the other targets with different weight bullets. Barrel time is a big part of accuracy.
20180111_121025.jpg
 
Last edited:
I just wish the pics would load! All of this talk is way over this rednecks head for sure! I guess Im kinda like William Munny, Ive always been lucky when it comes to killing things, or in this case working up an accurate load for a gun. What youre doing goes beyond my comprehension and I will be the first to admit it!
 
I would love to see the software that calculates barrel time. Is it as simple at 2650 FPS divided by a 2.5 ft long barrel? 1060 barrels per second?
 
fairchaser said:
I know guys who move their powder charge due to changes in temp, pressure and even elevation. There are other factors affecting speed over powder charge and pressures. I believe we lump these together in a node because it's the easiest thing to measure.

I've done most of my testing at 100 yds but when I moved out to 600, I found some more tweaking had to be done. Groups at 100, 200 and even 300 might not translate to 600 due to barrel harmonics. Like MUP says, the proof is on paper. Groups win matches.
Click to expand...
Fairchaser & MUP bring up some great points.....I am very comfortable using even factory loads out to 300 yards......it's having the confidence in the accuracy for the 400-700 yard shot that I care about for hunting....as I develop my loads for my .284 Winchester I'd appreciate your cumulative experience in load development and testing for these distances.....if it's accurate and consistent at 500-600 yards I am not going to worry about the 200-300 yard shot. I am out in California and will be hunting open lands in the West where it is not uncommon to make shots from 400-700 yards. Thank you in advance. BTW, I am doing a custom build using a Borden Ridgeline Medium Action so the COAL can be longer than the 2.71.
 
A fellow named Chris Long is the mastermind who, through tons of research, discovered and produced the barrel time list that I use in load calculation. As our first part in understanding nodes and barrel times, please read the paper Chris produced. Then I will start calculating loads for a rifle one of you guys have. We can look at different powders and bullet weights to see if we can achieve proper pressure, case fill, and barrel time as all three must come together to make a good load for testing. Please thoroughly read the paper at the below link.

 
jlanecr500 said:
A fellow named Chris Long is the mastermind who, through tons of research, discovered and produced the barrel time list that I use in load calculation. As our first part in understanding nodes and barrel times, please read the paper Chris produced. Then I will start calculating loads for a rifle one of you guys have. We can look at different powders and bullet weights to see if we can achieve proper pressure, case fill, and barrel time as all three must come together to make a good load for testing. Please thoroughly read the paper at the below link.

Click to expand...
Thanks for sharing this research. I read it once and it's pretty deep and mostly over my head but I think I got it. It makes sense and I would definitely like to try it.
 

Latest posts

Back
Top