I've read numerous pieces that discuss the benefits of slow burning powders as well as fast burning powders; that being said, how do you determine between the various powders as to which ones are considered slow burning and which are the faster burning powders? I've looked at various gun powder containers and no burn rates are listed.
Slow Burning Power VS Fast Burning Power?
- Thread starter onelastshot
- Start date
it will depend on what caliber and bullet weight to determine if a powder is fast or slow depending on your application,,
the same powder would be slow in one situation and fast in another,,
the same powder would be slow in one situation and fast in another,,
Do not be overly concerned with the label, slow, fast. Look in the loading manuals for the cartridge and bullet you plan to use and then look at the loads listed and pick a powder that gives good velocity and work with that powder. It helps to look at more than one manual. Also, Sierra gives a recommended accuracy load for a lot of cartridge and bullet combination.
Myself I pick the powders it give me the fill ratio how far down the barrel it takes to get 95% of the velocity and the Ammount burn rate in the barrel . Larry
Larry, I am sure you are making a very good point but I was not able to follow. Please give some more detail/explanation and maybe I can get it. Respectfully, Clyde
Get Quick Load it is a computer program that lists all the above.
Larry
My belief is that the best powder for a cartridge load is the slowest one that gets the velocity you want and fills or nearly fills the case. Here is another powder burn rate chart that I think gives a better feel for how the various powders compare. Fastest at the top and slowest towards the bottom. It is a continual graduation between fast and slow.
Vihtavuori Burn Rate Chart
It's difficult to explain. I recommend you grab a good reloading manual, ask Google and read a few chapters on interior ballistics. There are books written on this subject, which covers more ground that we can reproduce here.
Donald, I have a good understanding of the subject but I think Larry did not express himself very well. I was trying to get him to make his point more clearly but I did not want to sound critical. Clyde
^^This. QL is well worth the cost and makes powder selection very easy.
shoot4fun
Gold $$ Contributor
Fast during powders burn faster than slow burning powders but sometime, depending on case volume and other factors, a fast burning powder is as slow as you can use. Whew!
Not being a A-hole by that statement.
Case volume, bullet weights and max pressures allowed will put you in a "range" of powders that allow the best performance for that caliber within safe pressure limits.
If you take, for example, the loading data Hodgdon provides for the diminutive 17 Hornady Hornet you see that "slow" PISTOL powders suddenly become seen as very fast RIFLE powders and very fast RIFLE powders become slow RIFLE powders. Confused now?
I'd say it's best to look for efficiency and performance and forget about splitting hairs on fast v. slow burn rates. Especially now that there are powders showing up with the same burn rate as a existing powder but formulated to provide a totally different pressure curve.
Not being a A-hole by that statement.
Case volume, bullet weights and max pressures allowed will put you in a "range" of powders that allow the best performance for that caliber within safe pressure limits.
If you take, for example, the loading data Hodgdon provides for the diminutive 17 Hornady Hornet you see that "slow" PISTOL powders suddenly become seen as very fast RIFLE powders and very fast RIFLE powders become slow RIFLE powders. Confused now?
I'd say it's best to look for efficiency and performance and forget about splitting hairs on fast v. slow burn rates. Especially now that there are powders showing up with the same burn rate as a existing powder but formulated to provide a totally different pressure curve.
The powder that is most EFFICIENT in any rifle case is the one that provides the highest velocity and LEAST pressure. These powders are generally the top 3-4 listed in loading manuals. If you compare a few pieces of data from different manuals, there will be a common powder(s) that hover at the top of the list.
Now, a fast powder may give the desired results with less cost, such as using Varget in the 30-06 with 130gr-180gr bullets, it gives ok results, costs less and is kinder on the barrel, but, it doesn't give the same velocity as a slower powder would.
It must be understood that burn rates are NOT constant, case shape, bore size and expansion ratio play a big part in what burn rate is required.
As an example, large almost straight walled cases require a faster burning powder than large sharp shoulder designs, the reasons are many, but, simply put, the straight wall case doesn't restrict powder ingress and flow behind the bullet, therefore the powder required is faster, but, it behaves slower in that case design.
As a general rule, fast powders peak very quickly, in a rifle, this results in low velocity, while slow powders peak later and push on the bullet longer creating more velocity, even though MAP may be the same.
Hope this helps.
Cheers.
Now, a fast powder may give the desired results with less cost, such as using Varget in the 30-06 with 130gr-180gr bullets, it gives ok results, costs less and is kinder on the barrel, but, it doesn't give the same velocity as a slower powder would.
It must be understood that burn rates are NOT constant, case shape, bore size and expansion ratio play a big part in what burn rate is required.
As an example, large almost straight walled cases require a faster burning powder than large sharp shoulder designs, the reasons are many, but, simply put, the straight wall case doesn't restrict powder ingress and flow behind the bullet, therefore the powder required is faster, but, it behaves slower in that case design.
As a general rule, fast powders peak very quickly, in a rifle, this results in low velocity, while slow powders peak later and push on the bullet longer creating more velocity, even though MAP may be the same.
Hope this helps.
Cheers.
Go to www.ramshot.com under products and down load burn rate chart. It will give you a comparative view.(chart is 4yrs.old) Semi-autos need faster powders so they don't overwork their actions. Bolt guns can take advantage of slower powders for more mv.Be advised as mag.maniac said there are things that come into play. Good luck on your quest.
This is a very interesting subject. All powders are listed on a "Burn Rate Chart" in their relative "operating speed" if you will, in relation to the burn rate characteristics of other powders on the chart. Sounds like mud>>>and to some degree it is. You will find on various burn rate charts that a certain powder, at times, appears either further up (faster) on the chart or further down (slower) on the chart. I have A LOT of experience with a lot of powders. I have seen VVN550 listed as "slower" on a list than real life experience tells me it is. Then there is another "avenue" to look at. Take H4350, it is about as "slow" of a powder as you can reasonably use in a 6.5 x 47L. That same powder, used in a .300 Win Mag will act as a very fast powder would. Varget, used in a .223, is on the "slow" side. However, used in a 30-06 with 165gr pills, would be "fast" indeed! Once you have used many, if not most of the commonly used powders, you will get a good "working knowledge" of where they ACTUALLY are in the "fast-to-slow" burn rate. After you gain a good working knowledge you can then use that knowledge to find one or two powders that will REALLY work in a given application.
old_heli_logger
Gold $$ Contributor
Look your component combination up in your Nosler Manual and use their, "most accurate powder."
Now go to your bullets' manual for the min/max amount of powder to use.
Good luck!
Now go to your bullets' manual for the min/max amount of powder to use.
Good luck!
You've been advised to look at three if not four burn rate charts - if you do, you risk further confusion as some powders change position quite markedly between different sources. This is partly because the tests used may not be consistent between manufacturers / products, also because 'burn rate' is not a fixed standard with any relevant international standards, gauges to measure it against and so on. A powder may lie in one position in relation to others in one application eg 308 Win, but a different one in another cartridge with a different case capacity / charge size to bore ratio - say .30-06 or 7X57 Mauser.
That is why every burn rate chart published carries a warning somewhere on it that says it's for judging general broad applications and must never be used either to determine a specific application or to substitute charge weights from one powder to an apparently similar one lying alongside in a chart. A good example that we see in Europe is Czech Lovex brand SO65, a single-based tubular powder that in its manufacturer's burn rate chart is on the same line as Hodgdon VarGet. When VarGet was completely and utterly unobtainable in the UK for a period of 18 months some time back, people seized on this apparent interchangeability and thought SO65 would make a good alternative. It didn't! It is bulkier, has a considerably lower specific energy rating, and as seen in other people's burn charts, is also considerably slower burning - up to three steps slower in some I've seen. So, in typical optimal VarGet applications such as 308, it filled the case to compressed levels and produced mediocre MVs, large ES/SD values and often poor groups. Run it in 7mm-08 match loads, 7X64 or 7X57 sporting loads though and it can be a fine performer - a larger case and/or smaller bore giving a much lower expansion ratio.
The basic reason for having different burning rates is to provide a combination of peak chamber pressure and 'area under the [pressure/bullet movement/barrel-time] curve' that provides optimum MV within allowable pressures. Two primary factors determine what is a well suited powder in burning rate terms - the case size/capacity/charge weight to bore area ratio and the relative bullet weight in any given application. The larger the charge behind any bore size, the slower burning the powder needed. Have it too fast burning and the pressures go past red lines before the bullet has moved far enough down the barrel to increase the combustion chamber volume (internal fireformed case + the volume of the space behind the bullet base at any individual point of the charge burn.)
So small bore calibres require slower burning powders unless as in say .22 Hornet, there is a tiny case. The 45-70 and even the African dangerous game .458 Win Magnum by comparison use fast burners - because as the huge 45 cal bullet moves down the barrel, the combustion chamber volume rises very quickly.
A good way of seeing in practice how this works is to take a range of cartridges based on a single case, 308 Win and 30-06 being obvious examples. The 308 case has been used with little other change than neck diameter in five calibres on top of its original .30 - 243 Win, 260 Rem, 7mm-08 Rem, 338 Federal, 358 Winchester. Look up their loads in a loading manual and see what powders are used for the mid weight to heavy bullets, then look them up on a burn rate chart. 243 Win uses much slower burning grades than 338 or 358. This is purely case/charge to bore size ratio determined, sometimes called the effective expansion ratio, or how far the bullet must travel before combustion chamber volume doubles then trebles. (Although that looks at it in distance terms, the key factor is the time it takes a bullet to reach these waymarks as the % of the charge that has burned is determined largely by time from initial ignition and that in turn determines gas volume production.)
The other key factor that sees the need for different burning rates is bullet weight (affects inertia) in any given cartridge design, allied to the bearing surface length (which affects friction levels). A heavy, long bearing surface bullet has a great deal more resistance to acceleration / movement down the barrel than as light short one. Again, it comes back to distance travelled down the barrel / burn time and how quickly the combustion chamber volume is expanding as the charge burns through. Taking 308 Win as an example again, a 110gn bullet sees relatively fast burning powders employed because this short, low-inertia projectile moves forward then accelerates very quickly as soon as pressure builds up behind its base. A 230gn Berger Hybrid needs very much slower burning powders because the doubling of weight and much greater barrel contact sees a great reluctance to move at all, then much, much lower acceleration down the barrel. Use a powder suited to the 110 grainer with the 230 and the charge must either be reduced so much to keep pressures acceptable that the resulting MV will be very poor, or if the 110gn bullet load's powder and charge weight were simply substituted, the resulting pressure will break the rifle through a massive over-pressure before the bullet has moved more than a few millimeters. This is why a frequent cause of gun explosions with handloaded ammunition is the selecting the wrong powder when loading cartridges of different characteristics in a single session or getting plain confused over which powder is which - select very fast burning Vihtavuori N340 (a pistol/revolver cartridge powder) in mistake for N140 (a relatively slow burning rifle powder) and put 45 grains of the former behind a 150gn bullet in 308 Win and it's BANG, goodbye rifle, maybe bits of the shooter too, time!
That is why every burn rate chart published carries a warning somewhere on it that says it's for judging general broad applications and must never be used either to determine a specific application or to substitute charge weights from one powder to an apparently similar one lying alongside in a chart. A good example that we see in Europe is Czech Lovex brand SO65, a single-based tubular powder that in its manufacturer's burn rate chart is on the same line as Hodgdon VarGet. When VarGet was completely and utterly unobtainable in the UK for a period of 18 months some time back, people seized on this apparent interchangeability and thought SO65 would make a good alternative. It didn't! It is bulkier, has a considerably lower specific energy rating, and as seen in other people's burn charts, is also considerably slower burning - up to three steps slower in some I've seen. So, in typical optimal VarGet applications such as 308, it filled the case to compressed levels and produced mediocre MVs, large ES/SD values and often poor groups. Run it in 7mm-08 match loads, 7X64 or 7X57 sporting loads though and it can be a fine performer - a larger case and/or smaller bore giving a much lower expansion ratio.
The basic reason for having different burning rates is to provide a combination of peak chamber pressure and 'area under the [pressure/bullet movement/barrel-time] curve' that provides optimum MV within allowable pressures. Two primary factors determine what is a well suited powder in burning rate terms - the case size/capacity/charge weight to bore area ratio and the relative bullet weight in any given application. The larger the charge behind any bore size, the slower burning the powder needed. Have it too fast burning and the pressures go past red lines before the bullet has moved far enough down the barrel to increase the combustion chamber volume (internal fireformed case + the volume of the space behind the bullet base at any individual point of the charge burn.)
So small bore calibres require slower burning powders unless as in say .22 Hornet, there is a tiny case. The 45-70 and even the African dangerous game .458 Win Magnum by comparison use fast burners - because as the huge 45 cal bullet moves down the barrel, the combustion chamber volume rises very quickly.
A good way of seeing in practice how this works is to take a range of cartridges based on a single case, 308 Win and 30-06 being obvious examples. The 308 case has been used with little other change than neck diameter in five calibres on top of its original .30 - 243 Win, 260 Rem, 7mm-08 Rem, 338 Federal, 358 Winchester. Look up their loads in a loading manual and see what powders are used for the mid weight to heavy bullets, then look them up on a burn rate chart. 243 Win uses much slower burning grades than 338 or 358. This is purely case/charge to bore size ratio determined, sometimes called the effective expansion ratio, or how far the bullet must travel before combustion chamber volume doubles then trebles. (Although that looks at it in distance terms, the key factor is the time it takes a bullet to reach these waymarks as the % of the charge that has burned is determined largely by time from initial ignition and that in turn determines gas volume production.)
The other key factor that sees the need for different burning rates is bullet weight (affects inertia) in any given cartridge design, allied to the bearing surface length (which affects friction levels). A heavy, long bearing surface bullet has a great deal more resistance to acceleration / movement down the barrel than as light short one. Again, it comes back to distance travelled down the barrel / burn time and how quickly the combustion chamber volume is expanding as the charge burns through. Taking 308 Win as an example again, a 110gn bullet sees relatively fast burning powders employed because this short, low-inertia projectile moves forward then accelerates very quickly as soon as pressure builds up behind its base. A 230gn Berger Hybrid needs very much slower burning powders because the doubling of weight and much greater barrel contact sees a great reluctance to move at all, then much, much lower acceleration down the barrel. Use a powder suited to the 110 grainer with the 230 and the charge must either be reduced so much to keep pressures acceptable that the resulting MV will be very poor, or if the 110gn bullet load's powder and charge weight were simply substituted, the resulting pressure will break the rifle through a massive over-pressure before the bullet has moved more than a few millimeters. This is why a frequent cause of gun explosions with handloaded ammunition is the selecting the wrong powder when loading cartridges of different characteristics in a single session or getting plain confused over which powder is which - select very fast burning Vihtavuori N340 (a pistol/revolver cartridge powder) in mistake for N140 (a relatively slow burning rifle powder) and put 45 grains of the former behind a 150gn bullet in 308 Win and it's BANG, goodbye rifle, maybe bits of the shooter too, time!
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