What is Burn Rate?
While a gun powder explosion in the cartridge seems instantaneous, if you slow it down you will actually find that each powder has a different “burn rate,” or speed at which it ignites. This is similar to how gasoline burns faster than lighter fluid. Gas burns quickly with a rapid explosion while lighter fluid burns slower and longer. The same effect can be found in different gun powders.
It should be noted that burn rate, does not have a standardized unit of measurement. In fact, burn rate is really only discussed in comparison to other powders; there is no universal yardstick. This makes burn rate a slightly controversial and highly-debated topics, as some reloaders feel that burn rate is less important or practically inconsequential.
Burn rate is important, however, when you are loading magnum vs. non-magnum rounds. Typically, a non-magnum load will use faster burning powders while a magnum cartridge will need slower burning powders. Magnum rounds need to generate greater power. Therefore, they use slower-burning powders, which creates peak pressure for a longer timeframe. This is also needed to give the heavier bullet maximum power and velocity.
Specifics will change by cartridge and bullet type, but in general a fast-burning powder is used for light bullets and low-speed pistols and shotguns. Medium-rate powders are used for magnum pistols, while high-velocity, large bore rifle cartridges will need slow powders, as they deliver the most overall power.
It might seem like an instantaneous explosion, but some powders burn faster than others and you should take this factor into consideration when reloading your cases.
Pistol versus Rifle versus Shotgun Powders
Now that we have a solid understanding of powder characteristics and variables, let’s look over some important information that you need when reloading. This information will help you select the right products for your needs and give you a better understanding for the basic composition of a cartridge.
Handgun powder is going to burn faster, giving off the most energy in the shortest amount of time and distance. This is needed because the barrel of a handgun is shorter, so the explosion needs to be completed in about six inches. If you use a slow-burning powder in a handgun, you will likely have a bright flash at the end of the barrel. This flash might look impressive, but that visual explosion is wasted energy.
Because of the long barrel and increased power demands, rifle cartridges need a powder that burns slower, completing the explosion through the entire barrel and delivering consistent pressure from start to finish. If you use fast-burning pistol powder in a rifle, it will make too much energy at the beginning, giving off high pressures in the chamber. This brings the risk of damaging the gun. Slower powders push the bullet evenly down the barrel and keep pressure down while utilizing the most energy.
When choosing a shotgun powder, you will find that there is a lot of variety, largely changing based on the shot load. In general, heavier shot loads will require a slower burn rate, as it takes longer to sufficiently accelerate a heavy shot. If a fast-burning powder is ignited behind a heavy load, it could lead to excessive pressures, damaging the firearm and potentially causing injury. At the other end of the spectrum, a slow burning powder behind a light load, such as a bird shot, may not give enough power for sufficient energy and velocity.
This is an excerpt from Widener’s Reloading and Shooting Supply’s Guide to Smokeless Powder
Used with permission, photo courtesy of Wideners.
Deep Appalachian Roots
Widener’s has roots that run deep – in fact, the company goes way back into the late 1970’s. Of course, we weren’t selling much on the internet back then but it was in 1978 that Wideners.com founder Stan Widener first starting selling shooting supplies and reloading components. An avid hunter, it didn’t take much for the bug to swallow him whole and his passion for shooting sports quickly turned into a full-time career.
The Digital Age
Wideners.com got its start in 1996 when the company opened up shop on the world wide web. Sure, the first site wasn’t much to look at compared to today’s site but we were pretty excited to have the chance to serve shooters all over the country with primers, powders and more. It’s clear that a lot has changed in terms of technology but we still pride ourselves on always making time to treat our customers right. That includes making time to help new shooters and reloaders learn about the sport we love through tools like this handy Guide to Smokeless Gun Powder.
Still based in Appalachia, Wideners.com continues to pride itself on friendly customer service, competitive prices and most of our employees are, themselves, shooters and reloaders. That means when you call in with a question about ammunition or reloading components, odds are good we have somebody that’s willing to lend a hand and has actually used the product themselves. Pair that knowledge with fast shipping and a flawless inventory tracking system that ensures you don’t get stuck waiting on a backorder and you’ll be hooked!