On a number of websites and from some personal conversations I’ve had I hear a recurring theme (well, many, but I’ll chew on this particular theme for a bit), the desire to have an absolute minimum of gun powders in the inventory. Being somewhat of a minimalist myself, I am quite in accord with that sentiment. However, the more I thought, the less the answer seemed to fit on a bumpersticker or tee shirt. There are several considerations. So I’ve put these in the following order as I see consecutive. As usual, some may consider the matter different than I. That is probably good for all of us.
First allow me to dispel a rather common and deeply cherished myth. Fast powders are not intended for short barrels and slow powders intended for long barrels. NO! They are not!
Now I feel better.
Burn rate. To my mind this is the simplest consideration and therefore, I’ll start with that. I like simple. Probably most everyone has heard “For the X cartridge, powder Y is the best!” This was probably truer at one time than now. When smokeless gun powder was first developed, there was only one type and burning rate: “Poudre B(lanche)” – ‘White Powder” in French. Within a few years, several types (and differing burn rates) were developed, but most were relatively ‘fast’ by current standards. The latest information I possess shows 198 different powders (and burn rates) available in the world. To be more correct, many of these are not immediately available for retail sale in the U. S. (where I live; no doubt one in Great Britain or Europe or Australia or Tanganyika will find a somewhat different ‘picture’). Even so, the local gun shop has a display of half a barn door’s full. I haven’t counted them, but there are five or six shelves probably ten to fifteen (one pound) plastic bottles each displayed. That’s no less than fifty and probably not more than 90 or so powders and rates of burning. (I finally counted; 92 displayed at the time I counted.)
This is going to seem out of place, but it isn’t. What is the difference between handgun, shotgun and rifle powder? (We’ll leave out cannons and mortars.) One thing only: Burning rate. To the observant, one notes quite a few shotgun and handgun powders interchange. Some pistol powders can be used for small rifle cartridges.
The upshot of this is if one loads only for one category of arm – handguns, shotguns or rifles – one may exclude a number of the ‘other’ powders.
I don’t load for shotgun at all. I load very few pistol calibers. Mostly I load for rifles. So I can exclude the fastest fifty or so types of powders without further discussion. I have Alliant Power Pistol and either Alliant 2400 or Hodgdon 110 for handguns. The fact is, I do not load for .44 Magnum much anymore, so just the Power Pistol is my minimum.
Back to the main discussion. The basic question of ‘what kind of powder do I need for ____?’ The answer does not fit on a bumper sticker. The prime difference in the required burn rate is the speed with which the arm gets rid of pressure. (For those that disagree with this, or would word it differently, please read on.) One of the basic measures of any firearm is what is known as ‘expansion ratio’. This is the ratio of the volume of the internal burning chamber of a loaded round, compared to the total volume of that same interior of the cartridge case AND the total volume of the bore to the muzzle. A word of warning: When buying a firearm, do not ask the seller about the expansion ratio. A goodly number will just look at you as if you just grew a second head. A non-reloader will have no idea. Many reloaders just follow directions in the manual – as is proper. One may get more curious as time goes on, but one stays grounded in experience.
Consider a cartridge like the .220 Swift or .22-250 Remington. Both have a rather large case body and a rather small bore. One should see how the pressure of the burning powder takes longer to exit than a .45-70 Govt or .458 Winchester case. That is because the larger bore rifles have a larger ‘exit’. For that reason, firearms with a larger expansion ratio require a faster burning powder. The faster burning rate keeps the pressure high enough to keep pushing the bullet. The lower expansion ration arms require a slower burn rate to not overpressure the system and cause a failure.
Then we have another factor. Bullet weight. The heavier the bullet, the longer the time the pressure is held in the arm and not allowed to escape. Therefore, a heavier bullet – all other things remaining the same – the slower the powder must be. This seems somewhat contradictory to the first principle, but actually works in harmony. For instance, a ‘light’ .22 bullet in a .22-250 Remington can use a ‘faster’ slow burning powder than a ‘heavy’ bullet in the same cartridge using a ‘slower’ slow burning powder. A ‘heavy’ bullet in a .458 Winchester will use a ‘slower’ fast burning powder than a lighter bullet. So even for a ‘one rifle’ person, the minimum number of powders may be more than one. As example, the .30-06 Springfield – a venerable but somewhat ‘passé’ caliber – can handle bullets of 110 grain up to bullets of 220 grains. However, one will not get maximum velocity or efficiency using only one powder. Picking a single powder in the middle (for that cartridge) burning range, the light bullets will tend to limited by the ability of the powder capacity to provide enough pressure and pressure levels limits will not propel the heavier bullets as fast as one might want. With one cartridge and a single bullet weight – which can be easily done for hunting purposes – one can use one type of powder literally forever.
However, buying a box of ammo for the purpose would probably serve as well. And be cheaper and less bothersome in the long run.
Add to the confusion some bullets are constructed differently. To some degree they resist the deformation of the rifling differently than the typical lead core with jacket type bullet. I always see specific instructions and warnings on their packaging or in load books. Not likely to sneak up on one.
Then another ugly wrinkle rears its ugly head. Reloaders have long understood the reality of how one powder shoots better (more accurately or faster) when combined with a certain bullet of a particular brand (of the same weight). To my knowledge, this problem has never been suitably turned into a mathematical equation so the answer can be predicted. Experimentation is the word some use, trial and error is used by others. To further compound this difficulty, many find what works well in one firearm doesn’t always perform superbly in another arm of the same chambering. Usually it serves ‘okay’ but a special degree of accuracy requires some ‘tweaks’. In extreme cases, the reloaded ammunition will not fit the chamber properly.
Before I quit, some notes on the various listings of relative burn rates of powders.
Lists do vary from time to time about which powder is ‘quicker’ than another. Don’t hyperventilate, check a couple listings and most of all, READ THE LOADING MANUAL! This is a phenomenon of, under certain conditions, two specific powders may react differently. Not ordinary nor commonplace, but it happens.
Lists are made and ranked in order of burning rate. HOWEVER, no listing shows the relative burning rates in a percentage form. Nor are the rankings equally spaced. Numbers 99 and 100 are not guaranteed to be the same ‘gap’ as between 100 and 101. Do not attempt to use a relative burn list as a loading manual.
New powders are being introduced constantly. As mentioned, ‘Poudre B’ was the only smokeless powder in the game in 1886 or so. That was not the case for long. In the 1953 printing of Complete Guide to Handloading by Phillip B. Sharpe, the author discusses fifty-eight ‘known’ gunpowders available to the public at the time. Some were noted as ‘discontinued’ as of a certain date. As a young man in high school, I remember older reloaders talking about powders; for a long time I thought the (then DuPont) IMR (improved military rifle) line of gunpowders were the only ones made. Now there are far more and from many places in the world. No doubt, more change will come.