I have a formula for the amount of black powder that should be used to reject my nosecone, but the result I am getting is oddly low (0.3 grams) and it is because the amount of pressure (psi) I calculated to eject the nosecone is coming out to about .5 psi, which is definitely wrong. It is a 4 inch diameter tube, and I know the area calculations are all correct. However, when testing the force needed to pull off the nosecone with a spring scale, it is coming out to about 2500 grams, and when I flip it upside down and shake it, the nosecone slowly loosens up. If I shake it violently enough, it will fully fall out. Is the spring scale wrong, or do I need to fix my psi calculations? What am I missing, possibly? I am dividing the force needed to pull off the nosecone by the area of the circle made by the inside of my airframe. Please help. I checked and all the units are correct.