Different powders and burn rate

[Chiquita]

In reloading manuals, if a powder is not listed does that mean don't use that powder or simply means the reloading manual did not test that powder?

Why would one use slow burning vs fast burning?

I like to learn details of the burn rate, good info will be much appreciated. I do have the burn rate chart but all that tells me is the fastest to the slowest. I don't know how interpret that or maybe there is nothing to interpret and all I need to do is try different powders and see which one works best??

 

[Zero333]

Think of a cartridge like you spitting those paper spit balls through a straw. Try to follow my logic...

An overbore cartridge is like spitting through a thin straw. You can't blow too hard/fast because you'll pop your ears and eyes out. So that's the equivalent of using a slow burning powder so the energy doesn't build up too fast and cause too much pressure.

A underbore cartridge is like spitting through a very big in diameter straw. You can blow as hard and fast as you want because you need to build up pressure as fast as possible in a short time to make the bigger spitball fly fast. So it's the same as using a faster burning powder that build us pressure fast.

With most cartridges you want to use slightly faster powders with the lighter bullets compared to heavy bullets.

For example... 243 Winchester, with 105+ gr bullets is best to use slower powders between H-4350 and Retumbo burn rates.. I find H-4350 a bit too fast for 105+ gr bullets in the 243win, but many use 4350 and it works like a dream for them, while I use H-4831, IMR-7828, H-1000, RL-25/26, Retumbo burn rates.

Now, if you want to use 55-58 gr bullets in the 243win, you'll want to stick with powders in the Varget burn rate. This is again akin to the straw/spitball comparison.
Take the same size straw and shove a short light piece of paper down the straw and you'll be able to blow faster/harder to get it to shoot as compared to a long heavy piece of paper in the same straw. For the long heavy straw projectile you'll have to blow slower so you don't build too much pressure inside your mouth and blow your eardrums.

I hope you somewhat get my idea. Kinda silly, but it makes sense to me.

So if a powder is not in the reloading manual but is in the same burn rate as the ones listed that means it should be good to go, only the manual didn't test it. But just because 2 powders have the same burn rate doesn't mean they will produce the same energy with the same amount of powder charge weight. So if you can't find data for a specific powder, it's best to avoid it to be on the safe side.

 

[chromatica]

The Sierra manual lists recipes for a particular bullet in order of burn rate - fastest to slowest. I have taken some of my more accurate loads from entries near the bottom of the table. Slow powders tend to take up more room in the case. A 95% case fill tends to be more accurate than an 85% case fill.

 

[Doom]

Our responsive are more directed to rifle powders.
To be a little more direct on the don't use issue, the bullet manufacturers and Lyman do not list every powder that is satisfactory for a cartridge. If you compare Sierra to Nosler to Hornady for example for a 223REM with a 55gr FMJ you will see differences in the powders listed. They typically will all fall into the burn rate range referenced in ZERO's reply. This is why it desirable to have multiple reloading manuals.

There is one other pitfall to avoid. Most shooting is with jacketed lead bullets. However you need to be care of not taking 55gr FMJ bullet data and applying it to a monolithic (all copper) bullet such as a Barnes bullet, or vis-a=versa

Sometime, powder manufactures will be a little more liberal on the burn rate range of powders listed. This usually shows up as something like a compredssed load and low velocity/pressure (for a slow powder) or very low charge weigh and case fill for a fast powder. This is why it desirable to have multiple reloading manuals.

When it comes to pistol powder selection, bullet shape, composition and seating depth have a much greater effect on pressure and can actually affect the burn rate selection for the bullet and cartridge.

 

[K22]

Lots of good answers here to your question. The only thing I have to add is to stick to published reloading data - don't just pick a powder based on a burn rate chart.

Many powder manufacturer's offer free data books on their powders. The Hodgdon web site is another good source of information on powder load data. The loading manuals published by the bullet manufacturer's are some of the most reliable data because they test that powder with their bullets.

Like someone else mentioned, it's a good idea to have a few loading manuals to compare and contrast data. One of the best I've found is the Lyman Reloading Handbook. Another good one is the Sierra manual. I shoot a lot of Nosler bullets so I also have the Nosler Manual.

Most cartridges have well established powders that work well with a particular bullet. The specific aforementioned manuals I mentioned list "most accurate powder" tested. That doesn't necessarily mean that the others won't work well or even better in your rifle it just means it might be a good place to start your load development.

 

[Chiquita]

Thank you all for your replies. It is making sense.

I have the Sierra (online version), Berger, Hornady book and the magazine from Hodgdon that gets printed once or twice a year.

 

[6ShotsOr5?]

The Sierra manual lists recipes for a particular bullet in order of burn rate - fastest to slowest. I have taken some of my more accurate loads from entries near the bottom of the table. Slow powders tend to take up more room in the case. A 95% case fill tends to be more accurate than an 85% case fill.

@chromatica This is a good tip, thanks. I didn’t know to favor the slower powders, will be useful after I can buy them again. I have the Sierra manual but I just discovered they have an app and the app is very up to date (much better than the manual), more convenient to use, and free.

 

[Twicepop]

Case capacity and bore size also determine if the powder is classified as fast or slow. As an example, IMR4895 when use in something like the .222 Remington is a slow burning powder. When the same powder is used in a 30-06 it becomes a fast to medium burning powder.

 

[Rustytigwire]

^^^^^^^^ what they all said
You are on the right track. Keep looking at burn rate, load charts, the Sierra app is awesome. It kinda all comes together. Lots of variables. Be patient.
Target tells the story.

 

[338 dude]

Think of a cartridge like you spitting those paper spit balls through a straw. Try to follow my logic...

An overbore cartridge is like spitting through a thin straw. You can't blow too hard/fast because you'll pop your ears and eyes out. So that's the equivalent of using a slow burning powder so the energy doesn't build up too fast and cause too much pressure.

A underbore cartridge is like spitting through a very big in diameter straw. You can blow as hard and fast as you want because you need to build up pressure as fast as possible in a short time to make the bigger spitball fly fast. So it's the same as using a faster burning powder that build us pressure fast.

With most cartridges you want to use slightly faster powders with the lighter bullets compared to heavy bullets.

For example... 243 Winchester, with 105+ gr bullets is best to use slower powders between H-4350 and Retumbo burn rates.. I find H-4350 a bit too fast for 105+ gr bullets in the 243win, but many use 4350 and it works like a dream for them, while I use H-4831, IMR-7828, H-1000, RL-25/26, Retumbo burn rates.

Now, if you want to use 55-58 gr bullets in the 243win, you'll want to stick with powders in the Varget burn rate. This is again akin to the straw/spitball comparison.
Take the same size straw and shove a short light piece of paper down the straw and you'll be able to blow faster/harder to get it to shoot as compared to a long heavy piece of paper in the same straw. For the long heavy straw projectile you'll have to blow slower so you don't build too much pressure inside your mouth and blow your eardrums.

I hope you somewhat get my idea. Kinda silly, but it makes sense to me.

So if a powder is not in the reloading manual but is in the same burn rate as the ones listed that means it should be good to go, only the manual didn't test it. But just because 2 powders have the same burn rate doesn't mean they will produce the same energy with the same amount of powder charge weight. So if you can't find data for a specific powder, it's best to avoid it to be on the safe side.

That is probably the best explanation I have ever heard great job