Powders

wrangler yj · September 5, 2009, 09:04 PM

After looking over the manuals it seems that faster burning powders seem more for pistols than rifles. I don't know why and would just like the understanding and knowledge of why this is. Why can't someone use something like Varget in a pistol. Any impute would be great.

Sevens · September 5, 2009, 09:29 PM

The larger the space, the slower burning the powder needs to be so that the pressure doesn't peak too early.

I would think that putting a slow burning powder in a small pistol case would result in a powder puff load and a whole heap of unburnt powder flakes falling out of the muzzle -IF- the bullet had enough energy to make it out of the tube.

But when you put a large charge of a fast burning pistol powder in to a rifle case that SOB will explode and usually take the rifle with it.

Another good exercise for getting an idea of how this works is to look at loads for LARGE handgun rounds and see how they differ. For example, you can use a fast burning powder like Bullseye in 44 Magnum for 240 grain bullets if you want, but you tend to use a small charge of it. You don't get maximum bullet velocity, but the pressure is right up to SAAMI max. Now, take the same caliber and same bullet and use a slower burning magnum pistol powder-- let's say, Accurate #9 or H110, and what you get is a larger charge of this powder gives you much more velocity with the same or less pressure than the light charge of Bullseye that gave you less velocity.

Some folks who are just getting started at the bench will want to buy one powder and use it for EVERYTHING. Some powders are more flexible than others. But when you've done it for a while, you find that a $22 pound of powder not only lasts a long time, but picking the right one for each use gives you better results than trying to pick one and use it for everything.

wrangler yj · September 5, 2009, 10:16 PM

I've been reloading on my own now for about 4 years and do try different powders. But it has been just go by the books and nothing else. Thank you for the knowledge. I just got done earlier today reloading 100 44 mags and 100 44 spl. so I understand better now with what you said about the 44. Thank you once again.

**Unclenick** · September 5, 2009, 10:30 PM

Basically, you have to remember that pressure depends on how much gas you put in a fixed space (volume). When the bullet is seated in the case, the volume underneath it is small. When the bullet is several inches down the bore, the volume behind it is much larger than when it is just in the case. How much bigger is called the expansion ratio, but you don't need to worry about that to understand the basic principle. I only mention it because you will probably run into that term sooner or later.

So now let's assume you have two powders. One is fast burning and one is slow. Equal weights of both will make the same amount of gas. That is not true for all powder formulations, but for this example we'll stick to two powders for which it is true. So now you light the fast powder. Because it is fast, it burns before the bullet moves much, so it makes all its gas in the small volume behind a bullet that isn't very big. Now you burn a slow powder. It can't finish burning before the bullet has time to move pretty far down the barrel, so it finishes burning in a much bigger space. This means that if you used the same amount of both powders making the same amount of gas, the fast powder would make a much higher pressure because all that gas is packed into a much smaller space. The other way to look at this is that you can use a lot more of the slow powder to reach the same pressure because its gas is made in a larger volume.

So, for more total gas volume you use a larger quantity of a slower powder. This generally gives you a higher velocity, but it transfers energy less efficiently to the projectile. It is also harder to light and harder to get it to burn completely. That requires a minimum of pressure. Some powders are so slow that they can't reach the minimum of pressure needed to burn well unless the case has very high volume and the bullet is very small diameter. That's why some powders are too slow for pistols, with their small volume cases.

bignz · September 5, 2009, 11:33 PM

I agree with what has been said.

You will sometimes notice in low light situations (like at dusk or at a low light range) that using slow burners in a pistol will create a sparkler like muzzle flash. This is of course powder burning away outside the barrel. What a waste of perfectly good powder.

Sevens · September 6, 2009, 07:38 AM

Unclenick, on this subject and given the eloquent way you've described it, how would you go about finding a good load for a cartridge that's tiny and 95% of the time, shot from a short barrel-- but you need it for a l-o-n-g one?

Where I'm going with this: 124gr FMJ and 125gr LRN 9mm, out of a 16-inch carbine barrel of my full blowback K-T Sub-2k?

Does Quickload offer some insight in to this, or is it more of a "find load data with slower powders and see how they work" kind of proposition?

wrangler yj · September 6, 2009, 08:25 AM

So you need a fast burning powder in pistols because you want to burn all of the powder in the short time its in the barrel. You use a slower burning powder in rifles because you have longer barrels and more time to burn the powder. The faster burning powders will build up more pressure faster. You need this in the pistols. Pistols on average that have 2"-7.5" barrels. To get the bullet moving at a desired speed. In rifles you have longer barrels and more time to build up the pressure. Would this be pretty much correct.

bignz · September 6, 2009, 10:21 AM

wrangler - that's how I see it.

I have no experience with pistol rounds in a long gun - I'm sure many here do. Well I take that back - - 22lr. Now that is a small case that manages to work nicely in both pistols and long rifles. Factories must use magic powder.

September 5, 2009, 09:04 PM	#1
wrangler yj Member Join Date: July 21, 2009 Location: Southeastern Ohio Posts: 67	Powders After looking over the manuals it seems that faster burning powders seem more for pistols than rifles. I don't know why and would just like the understanding and knowledge of why this is. Why can't someone use something like Varget in a pistol. Any impute would be great.

September 5, 2009, 09:29 PM	#2
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	The larger the space, the slower burning the powder needs to be so that the pressure doesn't peak too early. I would think that putting a slow burning powder in a small pistol case would result in a powder puff load and a whole heap of unburnt powder flakes falling out of the muzzle -IF- the bullet had enough energy to make it out of the tube. But when you put a large charge of a fast burning pistol powder in to a rifle case that SOB will explode and usually take the rifle with it. Another good exercise for getting an idea of how this works is to look at loads for LARGE handgun rounds and see how they differ. For example, you can use a fast burning powder like Bullseye in 44 Magnum for 240 grain bullets if you want, but you tend to use a small charge of it. You don't get maximum bullet velocity, but the pressure is right up to SAAMI max. Now, take the same caliber and same bullet and use a slower burning magnum pistol powder-- let's say, Accurate #9 or H110, and what you get is a larger charge of this powder gives you much more velocity with the same or less pressure than the light charge of Bullseye that gave you less velocity. Some folks who are just getting started at the bench will want to buy one powder and use it for EVERYTHING. Some powders are more flexible than others. But when you've done it for a while, you find that a $22 pound of powder not only lasts a long time, but picking the right one for each use gives you better results than trying to pick one and use it for everything. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

September 5, 2009, 10:30 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Basically, you have to remember that pressure depends on how much gas you put in a fixed space (volume). When the bullet is seated in the case, the volume underneath it is small. When the bullet is several inches down the bore, the volume behind it is much larger than when it is just in the case. How much bigger is called the expansion ratio, but you don't need to worry about that to understand the basic principle. I only mention it because you will probably run into that term sooner or later. So now let's assume you have two powders. One is fast burning and one is slow. Equal weights of both will make the same amount of gas. That is not true for all powder formulations, but for this example we'll stick to two powders for which it is true. So now you light the fast powder. Because it is fast, it burns before the bullet moves much, so it makes all its gas in the small volume behind a bullet that isn't very big. Now you burn a slow powder. It can't finish burning before the bullet has time to move pretty far down the barrel, so it finishes burning in a much bigger space. This means that if you used the same amount of both powders making the same amount of gas, the fast powder would make a much higher pressure because all that gas is packed into a much smaller space. The other way to look at this is that you can use a lot more of the slow powder to reach the same pressure because its gas is made in a larger volume. So, for more total gas volume you use a larger quantity of a slower powder. This generally gives you a higher velocity, but it transfers energy less efficiently to the projectile. It is also harder to light and harder to get it to burn completely. That requires a minimum of pressure. Some powders are so slow that they can't reach the minimum of pressure needed to burn well unless the case has very high volume and the bullet is very small diameter. That's why some powders are too slow for pistols, with their small volume cases. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

September 6, 2009, 07:38 AM	#6
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	Unclenick, on this subject and given the eloquent way you've described it, how would you go about finding a good load for a cartridge that's tiny and 95% of the time, shot from a short barrel-- but you need it for a l-o-n-g one? Where I'm going with this: 124gr FMJ and 125gr LRN 9mm, out of a 16-inch carbine barrel of my full blowback K-T Sub-2k? Does Quickload offer some insight in to this, or is it more of a "find load data with slower powders and see how they work" kind of proposition? __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

September 5, 2009, 10:16 PM	#3
wrangler yj Member Join Date: July 21, 2009 Location: Southeastern Ohio Posts: 67	I've been reloading on my own now for about 4 years and do try different powders. But it has been just go by the books and nothing else. Thank you for the knowledge. I just got done earlier today reloading 100 44 mags and 100 44 spl. so I understand better now with what you said about the 44. Thank you once again.

September 5, 2009, 11:33 PM	#5
bignz Senior Member Join Date: February 17, 2009 Location: North Texas Posts: 196	I agree with what has been said. You will sometimes notice in low light situations (like at dusk or at a low light range) that using slow burners in a pistol will create a sparkler like muzzle flash. This is of course powder burning away outside the barrel. What a waste of perfectly good powder.

September 6, 2009, 08:25 AM	#7
wrangler yj Member Join Date: July 21, 2009 Location: Southeastern Ohio Posts: 67	So you need a fast burning powder in pistols because you want to burn all of the powder in the short time its in the barrel. You use a slower burning powder in rifles because you have longer barrels and more time to burn the powder. The faster burning powders will build up more pressure faster. You need this in the pistols. Pistols on average that have 2"-7.5" barrels. To get the bullet moving at a desired speed. In rifles you have longer barrels and more time to build up the pressure. Would this be pretty much correct.

September 6, 2009, 10:21 AM	#8
bignz Senior Member Join Date: February 17, 2009 Location: North Texas Posts: 196	wrangler - that's how I see it. I have no experience with pistol rounds in a long gun - I'm sure many here do. Well I take that back - - 22lr. Now that is a small case that manages to work nicely in both pistols and long rifles. Factories must use magic powder.