Explain Powder Selection Criteria to Me Please

[Ernest T]

I usually just use the powders listed under a cartridge in my reloading book, but how do I know what other cartridges the powder can be used for? For example, I bought Accurate 2460 for 55 Gr. hollow point boat tails in .223 Remington because it was listed in my Hornady manual. It worked fine for that cartridge.

This is what it says on the can: Accurate 2460 is a fast burning, double-base, spherical rifle powder that is a slower derivative of the AA2230 powder. It is suitable for small and medium sized caliber applications but with slightly higher loading densities than AA2230. It provides an additional option for shooters to fine tune and optimize loads and combinations with calibers ranging from the 223 Rem to the 308 Win. 2460 is within the threshold limit for M14 systems. Made in the USA.

I found a load on the Accurate website using 2460 in a 30-30 Winchester for 110, 150 and 170 grain projectiles. There isn't one for the 6.5 Creedmoor using 2460. The velocity of the .223 Remington is closer to the Creedmoor than the Winchester, but the Winchester bullet weights are closer to the Creedmoor. It just seems odd that there isn't a load for the 6.5 CM. Is it possible to work up a load for that powder in 6.5 CM without any published starting point?

This is the description of Accurate 2700 powder: Accurate 2700 is a medium burning, double-base, spherical rifle powder that is ideally suited for the 30-06 Springfield and other medium capacity calibers such as the 22-250 Remington, 220 Swift, and the 243 Winchester. 2700 provides excellent velocities and performance in the Winchester Super Short Magnum cartridges. Made in the USA

It seems very close to Accurate 2460.

What determines which powders are more suitable for certain cartridges and unsuitable for others?

 

[DShortt]

I would strongly caution you against trying anything other than published data. There are multiple variables in play including case capacity, bullet diameter, length and weight along with twist rates and barrel length. All of these effect pressure and it doesn't take a whole lot to make a serious mistake. Even published loads can create problems if you don't keep all the variables in mind which is why start low and work up is always advised. Better to be cautious and not experience a catastrophic failure.

 

[DLT]

I’m also in your boat. Yea I understand why not use some powders with some calibers but I do not understand why some are not even tested for load data that are in similar burn rates.

 

[DShortt]

I’m also in your boat. Yea I understand why not use some powders with some calibers but I do not understand why some are not even tested for load data that are in similar burn rates.

Because burn rates are not all there is to consider.

 

[Papa Charlie]

I tend to go directly to the powder manufacturers website and look up recommended applications and loads instead of using books that may or may not be current.
I also make decisions on what powders to buy based on the quality of the information they provide. Hodgdon/IMR is one of my favorites for load information.
To choose ranges of powders I generally look up the desired burn rates for the cartridge and then see what powders fall between the fastest and slowest recommended burn rate on the burn rate chart. This will narrow down the manufacturers and powders I have to research. I take this info and do the detail research on the mfg's website.

 

[CharlieNC]

Quickload or the free Gordon Reloading Tool are great resources to screen and evaluate many types of loading options as many critical safety parameters such as case fill and pressure are included. Provided with common sense and a cautious incremental workup in charge weight, you can try many options.

 

[Bill K]

Most, if not all the companies that put out Reloading data and manuals, test the powders in various cartridges and then list only the ones that they have found to be good for and safe too use.
Just follow the manuals from start loads and use and find a powder they list for a given cartridge, that proves accurate in YOUR RIFLE and go from there with it.
Don't rely on burn rate alone, the is more to it than that, for safe and sane reloading.

 

[Jager]

Beyond the caliber, you have to specify the bullet that you're intending to shoot.

With caliber and bullet in hand, the rules of thumb I look for when choosing a powder are those that produce near SAAMI maximum chamber pressure, at near 100% case fill, and with all or nearly all propellant burned before the bullet exits the barrel.

There are many exceptions to those rules of thumb, of course. But they'll get you to a good place pretty quickly.

Is Accurate 2460 a good powder for 6.5 Creedmoor? You don't specify the bullet, but using a Nosler 120 gr. Ballistic Tip as a quick example... QuickLoad shows 100% case fill at 46.6 gr. of A2460. That load would have a chamber pressure north of 100K psi, 40K over SAAMI max. Coming down to SAAMI max would require reducing the powder charge to around 40.2 gr of A2460, which only gives a case fill of 86.3%.

You don't have to shoot that combo to know it's not likely to produce anything worth repeating.

 

[RegionRat]

+1 on the advice above.
The full answer to your question requires a background in internal ballistics. That isn't something that fits within a post on an internet forum.

Internal ballistics is a long study in multiple disciplines. Unfortunately, at present there isn't a specific degree program that I am aware of, so there isn't a curriculum or list of classes or text books to recommend. The folks who get paid to do this type of work, have generally been introduced through apprenticeship and industrial experience.

Many "internal ballisticians" already start with engineering or chemistry degrees, but, some do not and as a result many ballisticians are not the same even though they carry the title. So, there is no text book or list of text books to point to. There are so few facilities in the world that produce powders or test internal ballistics, that there is no single independent place to send you for the answers. These things are taught differently by each place.

However, if you take it a step at a time and start reading and learning to run something like QL or GRT, you will see how many parameters are balanced out to get a successful recipe.

Gordon passed away recently, but you can still get the program and it is free. QuickLoad isn't free, but it isn't very expensive. Once you get past the burn rate chart and see how things work, you will have your answer.

These programs are capable of estimating pressure, which is paramount to safety margin. They roughly tell us if the load is useful or worth trying. You can learn the answer to your post question to a level of "good enough" by learning to run these simulations without all the trouble of learning the engineering behind them.

 

[mikecr]

how do I know what other cartridges the powder can be used for?
What determines which powders are more suitable for certain cartridges and unsuitable for others?

There are things that would have to be assumed as common for a list of cartridges applicable per powder.
I don't know of anything out there to show this (like in a table).
All I see are lists of powders per bullet/cartridge.

I see Reloadersnest is back online. That was a quick way to reverse research a range of cartridges for a given powder.
Example: https://web.archive.org/web/20170620002600/http://reloadersnest.com/frontpage.asp?CaliberID=18

 

[K22]

Maybe I'm missing something here which at my age is possible, , but published reloading data by reliable sources, i.e., Sierra, Nosler, Lyman, Speer, etc. have been tested so the work has been done for you. I don't see this as a complicated issue at all.

Where to start? Often the "most accurate" powder tested is a good place to start. That's not to say that it will produce the most accurate load in your rifle or that another powder won't work better but nevertheless it's a good place to start.

Any time you change components, especially bullets, there is good chance the results will change. So, if use Sierra's powder data for a 55-grain bullet for a 55 Nosler bullet, often the results will be different. So, using the reloading data published and tested by the bullet mfg. is a good approach in my opinion. Within limits, I've found that the bullet selected often is the most significant component affecting accuracy. For example, my 223 Rem rifles perform exceedingly well with Nosler bullets over a range of 3 to 4 powders in Nosler's published data.

 

[whatsupdoc]

The easy button is to simply ask what other shooters are using, there is billions of rounds
experience out there for the asking.

 

[Twdmar]

Mostly it comes down to reading the manuals and crossmatching which powders work for different cartridges. If you're looking for one do it all powder, h4895 might be the one.
Some cartridges are dimensionally similar in scale in like 223 and 308 and they can share a lot of powders but some powders' characteristics work in dissimilar cartridges under the right conditions. Powder for a 50bmg may also work in a 22-250ai.
Unfortunately, the only safe way is trust the data books. If you read enough of them, you'll find what powders you can use. If you have a bunch of different cartridges you load for, you're stuck buying different powders.

 

[CJ6]

Mostly it comes down to reading the manuals and crossmatching which powders work for different cartridges. If you're looking for one do it all powder, h4895 might be the one.
Some cartridges are dimensionally similar in scale in like 223 and 308 and they can share a lot of powders but some powders' characteristics work in dissimilar cartridges under the right conditions. Powder for a 50bmg may also work in a 22-250ai.
Unfortunately, the only safe way is trust the data books. If you read enough of them, you'll find what powders you can use. If you have a bunch of different cartridges you load for, you're stuck buying different powders.

This ^^^^^^^^^. And there in is the rub. Just looking at 1 source can limit what options you have for data on any specific powders use. For example Sierra may list IMR 4320 for use in a 270 Win. with 110-150 gr bullets and Hornady may only list uses for 100-110 gr bullets or not at all. Another example is say Hornady has loads listed for 8208 XBR in 308 Win in bullet weights from 110-155 grs. and not listed for 165-180gr weights but then lists charge weights for 190-208 gr bullets. That does not mean you can't use 8208 XBR in 165-180 grain bullets, it means you have too figure out your charge weights to start from based on the other bullet weights they have listed.

 

[lb-ft]

Lots of great direction has been given above. This might also help.

A)The smaller the bore in relation to the size of the case, the slower the burn rate for optimum performance.

Take for example the 308 case. We have everything from the 358 Winchester to the 243 Winchester, with the 338 Federal, 308 Winchester, 7mm-08 and 260 Remington in-between. The extreme large bore end of the spectrum, the 358, uses very fast burn rate powder (such as RL 7) for a rifle case that size, while the other extreme, the 243, uses very slow burn rate powder, such as H1000.

B) The bigger the case volume in relation to the size of the bore, the slower the powder.

Our example here is the 300 Blackout vs the 300 Norma Magnum. Both are .308 bore, and let’s shoot a 150 grain bullet from both. The Blackout might be appropriately loaded with a powder so fast burning it’s really on the pistol powder chart (H110), while the Norma might be loaded with a powder so slow, it’s suitable for 50 BMG.

C) The heavier the bullet for a particular cartridge, the slower the powder.

Let’s go back to the 243. Loaded with very light 55 grain bullets, a fast burning rifle powder is quite suitable, IE H322. Loaded with a 105 gr or heavier projectile and that slow burning magnum powder H1000 might give best results.

I hope this helps. One last tip, for lower recoil or more complete charge burn, (maybe you have a particularly short barreled hunting rifle), go with a faster burn rate powder from available published data.

Enjoy the tinkering. It’s half the fun.

 

[Ernest T]

Lots of great direction has been given above. This might also help.

A)The smaller the bore in relation to the size of the case, the slower the burn rate for optimum performance.

Take for example the 308 case. We have everything from the 358 Winchester to the 243 Winchester, with the 338 Federal, 308 Winchester, 7mm-08 and 260 Remington in-between. The extreme large bore end of the spectrum, the 358, uses very fast burn rate powder (such as RL 7) for a rifle case that size, while the other extreme, the 243, uses very slow burn rate powder, such as H1000.

B) The bigger the case volume in relation to the size of the bore, the slower the powder.

Our example here is the 300 Blackout vs the 300 Norma Magnum. Both are .308 bore, and let’s shoot a 150 grain bullet from both. The Blackout might be appropriately loaded with a powder so fast burning it’s really on the pistol powder chart (H110), while the Norma might be loaded with a powder so slow, it’s suitable for 50 BMG.

C) The heavier the bullet for a particular cartridge, the slower the powder.

Let’s go back to the 243. Loaded with very light 55 grain bullets, a fast burning rifle powder is quite suitable, IE H322. Loaded with a 105 gr or heavier projectile and that slow burning magnum powder H1000 might give best results.

I hope this helps. One last tip, for lower recoil or more complete charge burn, (maybe you have a particularly short barreled hunting rifle), go with a faster burn rate powder from available published data.

Enjoy the tinkering. It’s half the fun.

Thanks for that explanation.

 

[MAsSiVe MeDiC]

Beyond the caliber, you have to specify the bullet that you're intending to shoot.

With caliber and bullet in hand, the rules of thumb I look for when choosing a powder are those that produce near SAAMI maximum chamber pressure, at near 100% case fill, and with all or nearly all propellant burned before the bullet exits the barrel.

There are many exceptions to those rules of thumb, of course. But they'll get you to a good place pretty quickly.

Is Accurate 2460 a good powder for 6.5 Creedmoor? You don't specify the bullet, but using a Nosler 120 gr. Ballistic Tip as a quick example... QuickLoad shows 100% case fill at 46.6 gr. of A2460. That load would have a chamber pressure north of 100K psi, 40K over SAAMI max. Coming down to SAAMI max would require reducing the powder charge to around 40.2 gr of A2460, which only gives a case fill of 86.3%.

You don't have to shoot that combo to know it's not likely to produce anything worth repeating.

Your reasoning being because the case is 86% full as opposed to 99-100%? My experience has been that the most accurate loads are seldom full case loads…obviously when maximum velocity is not a priority.

 

[Jager]

Your reasoning being because the case is 86% full as opposed to 99-100%? My experience has been that the most accurate loads are seldom full case loads…obviously when maximum velocity is not a priority.

Correct. There are loads that shoot well at 86% load density. But they're not common.

I also don't disagree that nominal 100% load density loads are always the best, either... as there is an inflection point at that level where all the variables that influence case capacity intersect to produce a potential inconsistency. Some rounds are ever so slightly compressed. Some hit 100% load density exactly. And some are ever so slightly loose.

But near 100% load density is very often a good place to be. As are compressed loads, that take powder column consistency out of the equation altogether.

 

[Beiruty]

As mentioned, if you play with the free to own GRTools, you would start to understand some of the internal ballistics principles.

A reloaded rifle cartridge is nothing but 4 items
1) Caliber case (and its case capacity)
2) Primer
3) Smokeless gunpowder
4) Projectile

To simplify the problem at hand, Let us pick a case, say a 6.5 CrdM, and since SAAMI specify a large rifle primer, (none-magnum) we will use that.
The last 2 options are
A) gunpowder
B) Projectile

Some of the parameters of the gunpowder and projectiles:
A) Projectile: Bullet weight, Bullet overall length, and Bullet's profile and its Ballistic Coefficient.
B) Gunpowder: Burn rate, powder density Temperature stability


Now, let us consider the bullet that the shooter is most interested in. Here are some rules of thumb.

A) Bullet:
a) Weight: Heavier bullets for larger animals (hunting), or longer target range
b) Length: the heavier the bullet for the same caliber, the longer the bullet would be. Consequently, the longer the bullet, the less useful case capacity is available for the gunpowder when the final cartridge is loaded at a given overall length.

B) Powder: it has to fill a case and generate enough pressure to push the bullet to a given muzzle velocity at safe maximum pressure. Let us drop the Temp stability of the gunpowder for now, and focus on 2 factors, burn rate and powder density.
a) Burn rate:
The faster burning rate of the powder, the finer the powder would be, and vs versa. That should help us specify the powder density, or not to worry about it too much.
b) Powder density: since the case has fixed useful case volume powder, the gunpowder fill ratio would be the result of the powder charge (weight of the gunpowder) and the density of the powder used. Since the case would limit us to the quantity of the powder we can fill, we have to "optimize" what powder burning rate we select to fill up the case while maximizing the muzzle velocity while keeping the max pressure of the load safe.

Now, the crux of the problem: the Shooter would pick a bullet and would want to find what powder to choose.

If the shooter selected a heavy bullet for the caliber, he has to look for slow burning rate. Why? The heavier the bullet, it would accelerate slower in the barrel, and thus, to keep the pressure from rising extremely fast behind the bullet, we would use a slow burning gunpowder to keep the max pressure under the max safe pressure for that caliber.

Cool. Now our problem is reduced to selecting the gunpowder with given burning rate and the powder charge we can use.

Say, we started with a very slow burning rate for that caliber/bullet and the "manuals" did not list it. You may ask why it is not listed? Cause even when the case is filled to 100% the generated MV is too low for that load to be useful or acceptable for the user's needs. And, all the time, the max pressure of the load is below the max safe pressure for the caliber.

Then, a little faster powder would be tested. MV would rise for say 100% fill ratio while all the time, the max pressure of the load is below the max safe pressure for the caliber

We repeat the process, until the burning rate would start becoming fast for the caliber/bullet selected, MV would be force not increase by limiting the max powder charge, since the max load pressure is reaching the max safe pressure and thus, the powder charge has to be the maximum safe charge for that powder under that bullet in the selected case.

If we select a little faster gunpowder, the fill ratio would start falling since the pressure is rising faster and reaching the max safe pressure faster, and thus we have to still use lighter load (less case fill).

GRTools can illustrate this process quite easily.

In the next part, we will consider a case study, the user wants to shoot a 140gr HPBT in a 6.5 CrdM at 2.800" and he is wondering what powder to use? Can he use Accurate 2460?

 

[232]

I guess wildcatting is out of the question until known published data is available??