It is very real. It has two causes. Adhesion and cohesion. Adhesion is the bonding of two dissimiliar substances such as when you use a glue to hold two pieces of wood together. Cohesion is when two similiar substances bond together because the molecules of each piece bond Cohesion usaully requires some mechanical interaction or chemical interaction. Rust will join iron together.
Let us discuss adhesion first. If you use a case lube then you have placed an organic material of petroluem origin inside the case neck and it will slowly turn to a material that you would call varnish if it was in your favorite Holley double pumper. This varnish is basically a glue that your can see adhering to the engine parts. It will glue the bullet into the case neck.
Now let us speak of cohesion. Two similiar metals such as iron or in our case brass, if they are pressed together so that the matrix structures can complete themselves will become bonded by weak molecular forces. The more pressure the more the matrices are brought closer together and the more molecular bonds will form. For those of you who wish to verify the fact yourself, simply Google up "cohesion of metals". It amazes me sometimes the amount of useless stuff I actually know.
This reference has been written since I first studied this stuff 40 years ago and apparently what I know is out of date.
Now then those of you who have been living happily without knowing how to compute Van Der Waals forces can perform this simple experiment.
Go to your cabinet and get out some year old or perhaps only six months old loaded bullets and some empty cases. Size and seat a bullet in the empty cases to the same COL as the old bullets.
Take and screw the seating die down a quarter turn. Insert a newly crafted cartridge and seat it further. Take an old cartridge and seat it further. You will find that there is a definite "breaking loose" with the older cartridge.
Now then I do not shoot well enough to determine if this is enough to affect accuracy because I spent to much of my life doing stupid things like computing Van der Waals forces.
I personally go through the above proceedure of breaking the bullets loose every year for any bullets that I might hunt with that are left over from the previous year. I learned to do this about 30 years ago and maybe it is stupid, but it is what I do and there is a basis in science for it.
come on everyone, give the guy some latitude. metal does corode over time. Like others have said, that is probably what he is talking about. I have factory ammo that is 10-15 years old that obviously has some visible changes to it.
I used to re-load but now I "hand-load".
-- Well, at least I try --
They do stick but the only ammo that I ever reseated was the military
stuff that had used a asphalt based bullet sealant and all it seemed to
do was lower the standard deviation and the velocity a little.
As for welding cases to bullets I can weld every thing from the crack
of dawn to a broken hart but not bullets to cases . JUST KIDDING !
J E CUSTOM
Last edited by J E Custom; 09-13-2007 at 11:20 PM.
I've read two posts recently where individuals talked about lubing the inside of their case necks to help minimize this possibility of the bullets bonding to their case necks. This done in the effort to improve the consistency of their case neck tension. The more interesting procedure I read about was the use of an HB grade pencil from an art supply store. The individual coated the inside of his case necks with the pencil, and claimed the graphite in the pencil helped to ease the force required to seat the bullets but more importantly, provided more consistent neck tension. I've been considering using this method since it seems pain free, non messy, fast, and cheap. But I don't know if it would make a knat's azz difference or not.