Originally Posted by trueblue
What constitutes a "node" during load developement ?
I understand the desire to get the least velocity variance , but do not know what a node is, or what to look for .
A node is a point along a standing wave where the wave has minimal amplitude. For instance, when tuning a load to a rifle barrel it is desired to find a load that produces the least vibration or at least consistent vibration. It can also work the other way,you can tune a barrel to a load by changing the length or by adding weight. I don't believe a node is neccessaril talking about E.S and velocity, but is also a key part in finding a node. For what good is finding a node if your next round is outside of that velocity node?
In short for the ultimate accuracy you want to find a load that produces the least amount of vibration as well as finding a load that produces the most consistent ignition and burn. There are many things that can change once you develop this load, such as temperature, humidity, of course changing powder and bullet lots. barrel fouling etc...etc... this is why when developing a load I like to find a powder/bullet/primer combination that has a fairly wide acceptable node/consistent combustion. I have had many people ask if their rifle will shoot the same point of impact with and without a muzzle brake and my answer is no as you are adding weight to the end of the barrel, there have also been cases when the existing load for the barrel shot worse by adding weight to the end of the barrel, as well as some that have shot better. Depending on the contour of the barrel the variance will be different.
Sometimes it can be very frustrating and sometimes you can land right on the money! I definitely don't have all the answers for getting there, but I do know it sure is a lot of fun when you do......