|
Transplanted from old YW site:
gschwertley
As to the questions, "What can I use this powder for?
--------------------------------------------------------------------------------
This is a question that we see on this board and others. Reloaders come across or are given powder of one kind or another and it may be a propellant that they are not familiar with. For those of you who don't already know this, there are a few generalities you can go by in determining how to put any particular powder to its best use.
There are exceptions to the rule, but generally it is that lighter bullets tend to work better with faster powders and heavier bullets tend to work better with slower powders. This applies to both pistol cartridges and rifle cartridges. The burning rate of powders is described as a "curve" as in a graph. The burning curve of a fast powder peaks sooner and doesn't last as long as a slower powder. A slower burning propellant wants to ease the bullet down the bore and a faster one wants to slap it out. It's easier for a fast powder to slap a lighter projectile out the bore than a heavy one.
Naturally enough, mid-weight projectiles are apt to be best powered by propellants than fall in the middle ranges of speed; not fast and not slow.
One of the major exceptions to this principle is powders used with reduced loads. With reduced loads regardless of bullet weight, faster powders tend to be the norm. This is because in their reduced loadings, they build up lower pressures. Often cast bullet loaders use faster powders in small charges, but this isn't always the situation. Some cast bullet loaders use powders throughout the speed range up to and including very slow powders where because of the limits of case capacity, it's almost impossible to get an overcharge.
If you look at any good reloading manual that gives the muzzle velocity of the loads suggested, compare the powder charge to the velocity. You can easily pick out the most efficient powders for any given cartridge and bullet weight. Look for the powder charge that gives the highest velocity for the lowest charge. This natural indication of efficiency identifies good powders for the cartridge at hand.
For quick reference, you can find good relative burning rate charts for the various powders. Some of these have 200 or more powders listed, including obsolete types (which we sometimes run across). A glance at one such chart will tell you approximately what the burning rate of a given powder is.
One last note. Don't reduce charges of slower rifle powders without reading up on "why not" first. If you are going to get into the world of reduced charge reloading, do significant research on the subject first.
yockey5
I found out the hard way that if you reduce a slower burning powder too much, you will not have enough ignition to seal your case, thereby giving you a face full of hot gases! So stop, read, and listen. Thanks Gary!
coffee pot
gschwertley
Actually, that's not the worst of it. Secondary Explosion Effect (SEE) has been known to occur with insufficient charges of slow propellants. This is where the primer detonates the powder near the flash hole, and this creates a gas inside the case. The theory is that this gas then sets off in a higher-level explosion with the remainder of the powder. Another way I have heard it explained is that the spark sets off the powder near the flash hole, then jumps across air space inside the cartridge case and sets off the powder in the forward end of the case. These two fires burn back toward each other and set off the higher level secondary explosion. Even ballisticians wonder a little at the exact chain of events, as it happens very quickly and they have a hard time taking pictures of this phenomenon when it occurs inside a cartridge case. They are in agreement that it happens.
"Sehr schwer, mein Herr"
|
Login
Register
FAQ
