{"id":2288,"date":"2024-04-03T16:50:05","date_gmt":"2024-04-03T16:50:05","guid":{"rendered":"https:\/\/americangunpeople.com\/?p=2288"},"modified":"2024-04-03T16:50:05","modified_gmt":"2024-04-03T16:50:05","slug":"rifle-nodes-101-busting-age-old-load-development-myths","status":"publish","type":"post","link":"https:\/\/americangunpeople.com\/?p=2288","title":{"rendered":"Rifle Nodes 101: Busting Age-Old Load-Development Myths"},"content":{"rendered":"


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Finding a rifle\u2019s nodes is just one of many commonly-practiced load development procedures that handloaders follow in the pursuit of creating the most consistent, accurate ammo possible. The meticulous reloader will select quality powder, bullets, brass, primers, and other components, then methodically test different variables \u2014 primarily different charge weights and seating depths \u2014 to find what works best in each individual gun. For the 24 years or so that I\u2019ve loaded my own ammo, everything I\u2019ve read, watched, and done has focused on finding just the right combination of charge weight and seating depth to identify the sweet spot where velocities settle into a repeatable groove and groups tighten down to nothing. I\u2019ve burned countless pounds of gunpowder, and managed to make some good ammo by following these procedures. But what if all that, including finding a rifle\u2019s nodes, is just nonsense \u2014 an illusion created by small sample sizes?<\/p>\n

Getting Out of the Matrix<\/h2>\n

As I tell people what I\u2019m going to share with you, I feel like I\u2019m describing Neo in the movie The Matrix. <\/em>I was existing happily in my religious-like beliefs about rifle accuracy and reloading when, on a wolf hunt in Alberta<\/a>, I heard about a podcast episode that Hornady had published called Ep. 50 Your Groups are Too Small<\/em><\/a>. In the episode, Hornady Senior Ballistician Jayden Quinlan and Project Engineer Miles Neville presented some ideas that challenge many of the commonly-used methods for load development and gauging a rifle\u2019s accuracy \u2014 all based on thousands and thousands of rounds of test shooting they\u2019d done. Eventually I listened to it, and it made sense. I listened to it again, and it started changing the way I thought about and defined rifle accuracy. More importantly, I recognized the importance of using significant sample sizes \u2014 and how I\u2019d been misled by small sample sizes in my own testing and load development.\u00a0<\/p>\n

I listened to the follow-up episode (episode 52<\/a>), then another, and another \u2014 realizing that much of what I thought about load development and the methods I used were all based on small and, ultimately, invalid sample sizes. Sometimes I\u2019d strike gold with a great-shooting load, but now I know that I could have just picked a random charge weight and probably seen the same results. I felt pretty small at the thought of how much gunpowder and time I\u2019d wasted on load testing that was essentially pointless.<\/p>\n

We shooters and hunters often tend to stick with what we know works, or what we believe works, regardless of any evidence to the contrary. To complicate this matter, experienced reloaders who follow these practices and use good components and equipment usually do produce great-shooting ammo. However, Neville posed the valid question: \u201cIf a hundred different people develop loads a hundred different ways, and they all end up with comparable results, is it really the method that matters?\u201d\u00a0<\/p>\n

Like Neo in the movie, once I learned that everything I thought I knew about load development might be a myth, I couldn\u2019t turn back. Rather than remaining comfortable in my ignorance, I had to dive further into the rabbit hole to see if there might be a more efficient way to reload ammo, and a more effective way to quantify and measure rifle accuracy.<\/p>\n

Rifle Nodes: What Is a Node?<\/h2>\n

Many commonly-used terms in the shooting community aren\u2019t widely understood or used in a consistent context, so it\u2019s important to define what we are talking about. The technical term \u201cnode\u201d refers to the points on a wave at which the amplitude or displacement is the smallest. In terms of a vibrating object like a rifle barrel, it\u2019s the point at which the vibrating barrel moves the least. A rifle barrel does have nodes as it vibrates during and after a shot is fired, but when someone refers to \u201cfinding their rifle\u2019s nodes,\u201d they\u2019re referring to finding the charge weight and velocity that causes the bullet to exit at or near that node or dead spot in the barrel\u2019s movement as it vibrates back and forth. That\u2019s one dominant idea, but I\u2019ve heard a variety of theoretical explanations of the relationship between a barrel\u2019s vibrations, bullet exit timing, and charge weight.<\/p>\n

Whether you want to call it a node, sweet spot, or optimal charge weight, shooters have developed many methods for homing in on the best-shooting combination for their rifles. One of the most common methods is to run a velocity ladder test. There are many different ways these are conducted, but they usually involve incrementally increasing charge weights \u2014 usually one to three rounds per charge weight \u2014 that start low, then end up near or at book maximum. These can be valuable for getting a rough idea of what velocity each charge weight should produce, or tell you when you\u2019ve hit your pressure limit, but many reloaders use ladder tests to find \u201cnodes\u201d or flat spots \u2014 consecutive charges with relatively little change in velocity. In theory, the middle of this \u201cnode\u201d should produce consistent, forgiving velocity, even if your charge weight varies by a couple tenths of a grain.<\/p>\n

Another popular method for finding that sweet spot is called the OCW or \u201coptimal charge weight\u201d test. This primarily uses accuracy and point of impact to determine the best load. The OCW test prescribes loading three rounds per charge weight in a ladder test fashion, but shooting each charge weight at a separate aiming point. You\u2019ll then calculate your mean point of impact for each charge weight and, like a velocity ladder test, look for the tightest correlation of results. Your three consecutive charge weights that produce the closest points of impact highlight your \u201cnode.\u201d\u00a0<\/p>\n

At face value, a lot of this stuff makes sense. It seems logical that a given rifle would prefer certain charge weights of certain powders, depending on the bullet. But maybe it only seems logical because that\u2019s what we\u2019ve always believed and confirmed with small samples. After all, there\u2019s people that believe the earth is flat because we would be flung off a spinning, round earth. What if you pick a bullet for your rifle, and either it shoots well with a given powder, or not? It would change everything about how we approach load development \u2014 for the better.<\/p>\n

Test rifles from top to bottom: Savage 110 Carbon Predator in .223, Ruger American Gen 2 in 6.5 CM, and the Remington 710 in .30\/06. <\/figcaption><\/figure>\n

Find the Nodes, Then Test Them<\/h2>\n

As compelling as the tremendous amount of data compiled by the guys at Hornady is, I needed to see it for myself. They found that when using the small sample sizes (that everyone uses for these tests), a shooter will see consistencies in accuracy and velocity that are really just random noise within the outer limits of the system. The problem? They\u2019re not repeatable. When they increased their sample sizes, they saw all of these imaginary nodes disappear.\u00a0<\/p>\n

When I brought up the subject with Shooting Editor John B. Snow, he said that all his data had supported the idea that chasing nodes doesn\u2019t gain you anything. He and other high-level shooters at team events will even tailor their loads to target matching velocities to simplify drop and windage calculations between shooting partners \u2014 that\u2019s what he did in his Nightforce ELR Match prep<\/a> last year.<\/p>\n

I wanted to test this as thoroughly as I could, so I decided to use three rifles in three different calibers (.223 Rem., 6.5 Creedmoor, and .30\/06) with varying degrees of accuracy and components, and treat them as if I was trying to develop a load. I picked a powder and bullet, then ran both velocity ladder and OCW tests to find my nodes. Then, I loaded 30-shot samples at each \u201cnode,\u201d a sample at the \u201cantinode\u201d or worst-looking spot, and a fourth 30-shot sample to fill any big gaps in the charge weight spectrum. Any statistics textbook will tell you that 30 samples is a minimum good number for sample size, and though I expected some variability with that, they would certainly be more accurate than 3-, 5-, or 10-shot groups.<\/p>\n

Test Rifles<\/h3>\n

I selected three different rifles and calibers with different capabilities for this test. I wanted to see what a match-grade barrel would do, sure, but I also wanted to see if this matters for mid-priced rifles<\/a> and budget-grade rifles<\/a>. After all, I\u2019ve heard many arguments that budget rifles can shoot just as well as more expensive guns, it just takes developing the load it likes. I selected components and powders that were caliber-appropriate that I had in stock, but not with any particular strategy.<\/p>\n

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Finding the Nodes<\/h2>\n

The first test I conducted was a basic 10-shot velocity ladder, using one shot per charge weight. I used Hodgdon\u2019s Reloading Data Center<\/a> to find safe load ranges with my components, and incrementally increased charge weights by 0.3 grains with the 6.5 Creedmoor and .30\/06, and 0.2 grains with the .223. I noted spots with the smallest incremental changes in velocity and compared them to the additional three velocities from the OCW test (which I conducted next) to find my suspected nodes. These velocity \u201cflat spots\u201d seemed consistent between the 1-shot and 3-shot tests. I called this charge weight my \u201cvelocity node.\u201d<\/p>\n

After the velocity ladder test, I cleaned the barrels, re-fouled with 5 shots apiece, and conducted an OCW test, giving the barrels plenty of time to cool between groups. As mentioned above, I recorded velocities in my OCW test, but for this node, I correlated my points of impact to find my OCW node or \u201caccuracy node.\u201d Below is a table detailing the nodes I found, the \u201cantinode\u201d or least consistent charge weight, and the fourth charge weight that I tested. Velocities are the ones recorded during this testing session.<\/p>\n

\n\n\n\n\n\n\n
Rifle<\/strong><\/td>\nCharge Weight Range<\/strong><\/td>\nVelocity Node<\/strong><\/td>\nOCW Node<\/strong><\/td>\nAntinode<\/strong><\/td>\n<\/tr>\n
Savage .223 Rem.<\/strong><\/td>\n21.7 to 23.5 grains<\/td>\n23.1 grains \/ 2,736 fps<\/td>\n22.3 grains \/ 2,598 fps<\/td>\n22.3 grains \/ 2,535 fps<\/td>\n<\/tr>\n
Ruger 6.5 CM<\/strong><\/td>\n39.1 to 41.8 grains<\/td>\n41.5 grains \/ 2,611 fps<\/td>\n40.6 grains\/ 2,529 fps<\/td>\n39.7 grains \/ 2,468 fps<\/td>\n<\/tr>\n
Remington .30\/06<\/strong><\/td>\n54.8 to 57.5 grains<\/td>\n56.9 grains \/ 2,751 fps<\/td>\n56.6 grains \/ 2730 fps<\/td>\n55.1 grains \/ 2,652 fps<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

Next, I would increase the sample size to see how these nodes would hold up to more scrutiny. I did note that the velocity and OCW nodes I found for the .30\/06 were only 0.3 grains apart, but both of the other rifles showed significantly different nodes in each test. I found the OCW node and velocity \u201cantinode\u201d to perfectly line up at 22.3 grains of powder in the .223.<\/p>\n

Testing the Nodes<\/h2>\n

To test both nodes and the other two charge weights, I loaded 30 rounds of each, plus 5 fouling shots. I fired these test batches over the course of two different days, and a temperature difference of around 15 to 20 degrees between days. I tested the velocity node and antinode the first day at about 5 degrees, then the OCW node and fourth charge weight on the second day at about 20 degrees. I fired each 30-shot aggregate in the same format: 5 3-shot groups, then 3 5-shot groups, letting barrels cool between groups. I did this to see and show the variability in group sizes with small samples, and I used group analysis software to correlate points of aim to show extreme spread of the group and calculate mean radius (the average distance by which shots missed the center of the group). I recorded each shot\u2019s velocity in the test, and came away with 30-shot samples for reasonably accurate velocity average and standard deviation figures.<\/p>\n

If these nodes are real, or any optimal charge weight exists, one of these test samples should show significantly better \u2014 or even just different results than the others. The Hornady crew claimed to have found no significant change in group size with varying charge weights \u2014 except that group sizes seemed to decrease slightly as charge weight decreased. What would my data say? After over 600 rounds fired, recorded, and tabulated, here\u2019s what I found:<\/p>\n

\".223
For my OCW tests, I fired three shots of each charge weight at an aiming point, then calculated mean POI for each group. <\/figcaption><\/figure>\n

Savage M110 Carbon Predator: .223<\/strong><\/h3>\n

This was the most accurate rifle in the test, one that I\u2019ve used to evaluate .223 and 5.56mm ammo<\/a>, and it will reliably print 20- and 30-shot groups at an inch or less at 100 yards with several types of ammo.\u00a0<\/p>\n

Determining the Nodes<\/h4>\n