Pellet sizers and sizing is like running barefooted in the dark where you have no idea if the ground is such as slick as ice, dirt, pavement, pebbles, or rocks. Now, you decide to size the shoes (pellets) and you decide on some 10 inch shoe size (254.00mm). Great! But you are not done because not all two people have the "exact" same foot size. Notice that I did not say foot "length" because feet are not perfectly rectangular in shape, they also have curvatures, densities, skin textures and different type of socks (Pb + %antimony, or PBA), unless you wear sandals then you wear no sock type (100% Pb only, which by the way is impossible to attain better than 99.9999% Pb, similar to H2SO4, or zero Kelvin, or perfect vacuum, or the speed of light, or the true value of pi etc. etc.). The variables are more than the caliber because no two barrels have the "exact" same size caliber tolerance to within one lead (Pb) atom diameter, so one barrel either before or after the manufacturing process will be either one lead atom diameter bigger, or smaller due to wear and tear of tooling and specification changes due to the stress and strains of the manufacturing process. In essence, modern man, no matter how modern he is cannot manufacture a test tube baby that will win the Olympics.Like the Greeks did upon the birth of a child, if it showed any form of deformity they would toss it over a precipes. Now, that is one wild and crazy type of "sizing". I say "Every pellet has its God given right to be shot!" What I find interesting is how modern man applies discrimination, segregation, prejudices and biases to projectiles (pellets). Why don't we have an NBA team with all pygmies that are white guys? I don't know, but what I do know is that in order to have pure accuracy you need pure gun an pellet precision (repeatability) AND knowledge and skill of the shooter. You can cancel out the knowledge and shooter skill of the equation if you attach the gun to a vice attached to the moon where there is no weather, or air variables. As to the other variables of the gun are the number of land and grooves and their depth and finish along with the metallurgy and metrology of the Pb pellet, so there is no quick trick to an answer. The fun and joy of airgunning is not just jerking the trigger, hoping, praying, wishing that you hit what your intended target, but the shear joy of calculating the myriad of variables, predicting and testing you hypothesis for accuracy then narrowing it down from wild guesses to 100% certainty. When I accomplish that, I will be ready to die and move on to a new challenge, which will be coming back to life. In essence; for example, a 0.177 caliber, JSB Monster pellet perfectly symmetrical in its center of gravity and center of force, weighing exactly 13.45 grains and a head diameter of 4.545mm with a skirt of 4.555mm can come out of a barrel at a velocity of 819 feet per second and out of its twin brother barrel at 821 feet per second does NOT mean that it came out at 820 feet per second, which is why we have the Olympic Games, people die, I miss Jesse Owen. In ;, pellet sizing works and it doesn't work; sometimes for the better, sometimes for the worse, and everyone is unique because "cookie-cutters" are only theoretical; especially when you do ballistic analysis like I do at the planck level, which by the way, is addicting. Picture this in the future: "Hello, my name is Francisco and I am a ballistic planck addict for over 55 years." "Welcome Francisco!". The future is tomorrow, which will never come because we are stuck in the present. A theoretical pellet once told me that time travel is inevitable.