Fast burning Powders vs. Slow burning?

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Slow powders produce an extended pressure curve, good for long barrels. Short barrels don't do as well with slow powders. place a sheet (or a chronograph for that matter, anything...) in front of the muzzle of a few short and long barrel guns of a given caliber and you'll notice alot more unburnt powder with slow powder / short barrel. faster powder / short barrel not so much. Unburnt powder = wasted energy. What we're trying to do is maximize the area under the pressure curve. Peak pressure limit is limited by action and case strength, time is limited by barrel length. the trick is to find the combination that maximizes the area for a given barrel length / bullet wt in a given caliber. Many combinations make this a task with many answers, hence many opinions.
Unburnt powder is unburnt powder. Nothing more or less. Some of the best loads for velocity on certain cartridges don't reach a complete burn in a barrel of reasonable length. That doesn't keep them from creating the best velocity from that cartridge.

Powder burn rate is irrelevant to the barrel length equation and barrel length is irrelevant to the powder burn rate equation. The variables that matter are the ratio of case volume to bore diameter and the expansion rate of the cartridge/bullet weight/pressure combination. A cartridge is going to have a certain range of powder burn rates that are suitable for a given bullet weight. Going with a faster powder is going to mean a very steep pressure rise and while remaining within pressure limits of the cartridge, insufficient gas volume to maintain good pressure and a resultant decrease in velocity compared to a powder within the proper range. Going with a slower powder usually fills the case before the pressure is high enough to even provide proper burn for the powder. The typical result is a very low velocity and a lot of unburned powder.
 
Seems like if hot gases are lit outside the gun that is wasted energy/propulsion.
Not really. There is no way to capture it because there is no way to introduce more oxygen. It is excess energy, but is isn't wasted because "wasted" would imply that it could actually be used. If you want to talk about wasted energy, if your rifle/handgun barrel is not long enough that the bullet has completely quit accelerating before leaving the muzzle, you're wasting energy. It would take a *really* long barrel to realize that type of energy transfer and it would still be prone to muzzle flash.
 
helotaxi said:
Samari Jack said:
Seems like if hot gases are lit outside the gun that is wasted energy/propulsion.
Not really. There is no way to capture it because there is no way to introduce more oxygen.
I thought smokeless powder supplied its own oxygen for combustion ...


TygerAR said:
As a general rule, can I make the assumption that fast burning powers are better for low charges where a round will get a more complete burn, where Slower powders will give more velocity with less pressure at higher charges?
voicomp said:
I keep thinking there "should" be a chart somewhere with conversion ratios for various powders. Something like 'Use 80% the weight of Powder X to get the same zing as Powder Y". It seems to me that would make sense, at least for powders with similar burn rates.

I would also be interested in data on powder charge vs case capacity. Some sort of resource table with data like "recommended charge of powder Y in a 9mm load should be safe in .357 Sig
When I started match shooting, I asked several seasoned local and regional USPSA match shooters which powders were suitable for target loads in 9mm and 45ACP. I got varied responses that depended on the pistol, barrel length, bullet weight and velocity desired.

Of the suggested powders, I tested Bullseye, Clays, Titegroup, W231, Universal, WSF and HS-6 with FMJ bullets. Over the years, I have tested other powders but consider W231/HP-38 to be the "middle line" that separates more faster burning pistol powders that produce acceptable/optimal accuracy target loads at mid-to-high range load data. I consider Unique and slower burning pistol powders more suitable for full-power loads but these will often burn dirty at start-to-mid range load data and won't achieve acceptable/optimal accuracy until high-to-near max load data.

Ultimately, I think it will depend on the shooter. For me, accuracy is everything and holes on target speak volumes. On some match practice days, we tried each other's match loads loaded with different burn rate powders. With the same pistol, different shooters produced different level of accuracy and stage times depending on the load. Some preferred the faster burning powder loads with snappier recoil while others preferred the slower burning powder loads that pushed. Regardless, we concluded that target accuracy and stage times will ultimately be the determining factors unless you have specific requirements, such as making major power factor velocities, which will narrow your powder choices.
 
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Instead of guessing, this is what the powder manufacturers have to say about their powders and the intended/most suited applications (powder descriptions were pulled from manufacturers' websites and this website - http://www.reloadbench.com/gloss/powders.html


Powders listed by burn rate - http://www.hodgdon.com/burn-rate.html

Alliant Red Dot
This double base propellant was designed as a shotshell powder and may well be the most popular of its type. It is also a popular selection for many handgun and cast bullet rifle loads. It takes its name from the color coded granulations mixed into the propellant.

Alliant Promo
America's number one economy-priced 12 gauge target powder. Promo has the same burn speed as Red Dot, but is more dense, thus requiring a smaller bushing to obtain the same charge weight. Available only in 8 lb. containers.

Principal Purpose: Light and standard 12 ga target loads.
Secondary Uses: Handgun loads

Hodgdon Clays
Introduced in January, 1992, CLAYS gunpowder has "taken the clay target world by storm". It is the cleanest burning , most consistent 12 ga. 7/8., 1 oz. and 1 1/8 oz. powder available today, the preferred choice of competitive target shooters.. The superb burning characteristics of this powder produce soft, smooth recoil and excellent patterns. These features transfer directly to handgun applications where target shooting is the main goal. 45 ACP and 38 Special are only two of the cartridges where CLAYS gunpowder provides "tack driving" target accuracy with flawless functioning.

IMR "Hi-Skor" 700-X
This extruded flake type powder is ideally suited for shotshell in 12 and 16 gauge where clay target and light field loads are the norm. It doubles as an excellent pistol target powder for such cartridges as the 38 Special and 45 ACP and many more.

This is one of two double base powders marketed to reloaders by IMR.

Alliant Bullseye
America's best known pistol powder. Unsurpassed for .45 ACP target loads. Billions of rounds have been loaded with Bullseye since it was introduced in 1913.

Principal Purpose: Handgun loads

Bullseye is a double base powder and perhaps the most popular handgun powder in the U.S. It has proven extremely accurate in a wide range of standard velocity handgun cartridges and will offer maximum and extremely uniform ballistics. It is probably the powder most used to load pistol and revolver cartridges. It is ideal for the tiny 25 ACP as well as the 45 ACP. It is perhaps most often used for target loadings for the 38 Special.

Hodgdon Titegroup
As the name implies, this spherical propellant was designed for accuracy. Because of the unique design, this powder provides flawless ignition with all types of primers including the lead-free versions. Unlike pistol powders of the past, powder position in large cases (45 Colt, 357 Magnum and others) has virtually no effect on velocity and performance. Cowboy Action, Bullseye and Combat Shooters should love this one! TITEGROUP has it all, low charge weight, clean burning, mild muzzle report and superb, uniform ballistics.

Alliant American Select
Ultra clean burning premium powder makes a versatile target load and superior 1-oz. load for improving clay target scores. Great for Cowboy Action handgun loading.

Principal Purpose: 12 ga. target loads
Secondary Uses: Cowboy action handgun loads

Accurate Arms Solo 1000
Single-base, flake shotgun powder. Solo 1000 was the pioneer in the clean burning revolution and is an excellent choice for trap, sporting clays, and skeet shooting. Solo 1000 is an ultra clean burning powder that is well suited for target handgun loads in 45 ACP and Cowboy Action.

Solo 1000 A fast ultra-clean burning single base, flake powder ideal for 12 gauge shotguns. Highly uniform grain size. The champion's choice for 12 gauge clay targets or indoor/outdoor .38, and .45 ACP.

Alliant Green Dot
Smokeless shotshell powder. It delivers precise burn rates for uniformly tight patterns and lower recoil. Versatile for target and field. Slightly slower burning than Red Dot this double base powder incorporates a small amount of green colored granulations, hence its name. It is popular for applications similar to Red Dot.

Winchester WST

Winchester Super Target is a shotshell powder by design and generally replaces the now discontinued 452AA. It is also used by many handgun target shooters.

IMR Trail Boss
Designed specifically for low velocity lead bullet loads suitable for Cowboy Action shooting. It is primarily a pistol powder, but has some application in rifle. It is based on a whole new technology which allows very high loading density, good flow through powder measures, stability in severe temperature variation and most importantly, additional safety to the handloader.

IMR PB
Named for the porous base structure of its grains by which the burning rate is controlled, PB is an extremely clean-burning single-base powder. It gives very low pressure in 12 and 20 ga. shotshell target loads and performs well in a wide variety of handgun loads.

Accurate Arms No. 2
Accurate No. 2 is an extremely fast burning, double-base, spherical handgun powder suitable for use in a wide range of handgun calibers. Low recoil and low flash make No. 2 well suited for use in short barrel, concealed carry applications. No. 2 is a non-position sensitive powder and low charge weights make it an economical and versatile choice for high volume handgun shooters.

Ramshot Zip
ZIP is a clean burning, double-base propellant designed for a wide range of handgun calibers. Low charge weights make it the most economical and versatile choice for high volume shooters with the added benefit of low recoil, low flash and minimum residue. 9mm, 40 S&W, and 45 ACP are just a few of the cartridges that are well-matched with this powder.

IMR SR-7625
This is a single base powder intended for shotshell and handgun loads. It is also used in many lead bullet rifle loads. This is the fastest burning propellant in the canister grade SR series. The SR nomenclature of this and other IMR propellants using the same letters stands for Small Rifle; a confusing name for seldom used powders.

Hodgdon HP38 (now same as Winchester 231)

HP38 is a spherical powder that is great for low velocity and mid-range target loads in the .38 Special, .44 Special, and 45 ACP.

This double base spherical powder is manufactured by Olin and sold under the Hodgdon name. It will nearly duplicate the performance of Winchester 231 and it is extremely fast burning. The name was derived from Handgun Propellant ideal for the 38 Special. Hodgdon suggests it is a perfect candidate not only for the 38 Special but also for the 9mm Luger and the 45 ACP.


Winchester 231 (Now same as Hodgdon HP38)

One of the most popular reload propellants, 231 is a ball pistol powder ideally suited to the 38 special, 45 Auto, and 9mm standard loads. Consistency, clean burning, low flash, and a broad range of applications make this powder a choice for any pistol cartridge reloader.

It is highly favored for its well known accuracy potential.

Alliant Unique
Now cleaner burning! Most versatile shotgun/handgun powder made. Great for 12, 16, 20 and 28 gauge loads. Use with most hulls, primers and wads.

Principal Purpose: All-around shotshell powder, 12, 16, and 20 ga.
Secondary Uses: Handgun loads

Most versatile shotgun/handgun powder made. Great for 12, 16, 20 and 28 gauge loads. It is also a fine choice for cast bullets in many rifle cartridges. It has long been considered the very best selection for the 45 Colt cartridge. It is a good choice for the handgunner wanting slightly higher velocities in a wide range of calibers. It works in the small 25 ACP as well as the 44 Remington Magnum.

Hodgdon Universal
Handles the broadest spectrum of cartridges for both pistol and shotgun. This is the Clays gunpowder technology designed for 28 gauge shooters. From the 25 ACP to the 44 magnum and 28 gauge to 12 gauge, Universal Clays provides outstanding performance. As with all the "CLAYS" series powders, clean burning and uniformity are part of its attributes.

Alliant Power Pistol
Principal Purpose: High performance 9mm, .40 S&W and 10mm
Secondary Uses: Moderate pistol cartridges

Designed for high performance in semi-automatic pistols and is the powder of choice for 9mm, .40 S&W, .357 SIG and 10mm.

Alliant Herco
Since 1920, a proven powder for heavy shotshell loads, including 10, 12, 16, 20 and 28 gauge target loads. The ultimate in 12 gauge, 1-1/4 oz. upland game loads.

Principal Purpose: Heavy shotshell loads 10, 12, 16, 20 & 28 gauge
Secondary Uses: Heavy handgun loads

A relatively slow burning shotshell and magnum handgun cartridge propellant, Herco is a double base type with coarse granulations. Its use is mostly for heavy or magnum type loadings.

Winchester WSF
Winchester Super Field is another Winchester shotshell powders having applications in handgun cartridges, especially for competition loads.

IMR "Hi-Skor" 800-X
This large grained flake powder is at its best when used in heavy field loads from 10 gauge to 28 gauge. In handgun cartridges, 800-X performs superbly in cartridges like the 10mm Auto, 357 Magnum and 44 Remington Magnum. Excellent velocity and uniformity translate into top accuracy.

This propellant has similar design applications to "Hi-Skor" 700-X. Its burning rate is conductive to obtaining high velocities in certain handgun cartridge applications. The geometry of 800-X hinders uniform metering from powder measures and thus most users prefer to weigh every powder charge. This is the other double base powder marketed to reloaders by IMR.

IMR SR 4756
This fine grained, easy metering propellant has long been a favorite of upland and waterfowl handloaders. Top velocities with great patterns are legendary. Like 800-X, SR4756 performs extremely well in the big handgun cartridges.

This is single base propellant is primarily designed for shotshell applications requiring a slow burning propellant. It is also used for some handgun loads and some lead bullet rifle loads.

Ramshot True Blue
Perfect powder for classic calibers such as the 38 Special, 44 Special, and 45 Long Colt. Its a double-base, spherical powder with great metering properties that make it an ideal choice for consistent results using high volume, progressive reloading equipment. It works well with cast bullets and is also an excellent choice for 9mm law enforcement rounds.

Ideal Calibers: 9mm, .38 Special, .357 Mag, .45 ACP

Accurate No. 5
Double-base, spherical handgun propellant. This powder is extremely versatile and can be used in many handgun calibers. No. 5 offers a wide performance range from target and Cowboy Action applications to full power defense loads. This powder meters well.

Use of this fast burning double base spherical handgun cartridge propellant starts with the 32 H&R Magnum. It has also been used for the 9mm Luger, 357 Magnum, 38 Super Auto, 40 S&W (with superb accuracy), 10mm Auto, 44 Remington Magnum and 45 ACP with outstanding results. No. 5 is Accurate's most popular handgun propellant.

Hodgdon HS6

Nomenclature is short for Hodgdon Shotshell type number 6. It is basically a shotshell powder that has handgun and cast bullet applications. HS-6 is a fine spherical propellant that has wide application in pistol and shotshell. In pistol, 9mm, 38 Super, 40 S&W and 10mm Auto are some of the cartridges where HS-6 provides top performance. In shotshell HS-6 yields excellent heavy field loadings in 10 ga., 12 ga., 20 ga., and even the efficient and effective 28 ga. HS-6 is truly an outstanding spherical propellant. HS-6 is identical to Winchester's discontinued 540.

Winchester AutoComp
AutoComp is extremely fine in the 38 Super, 9mm, 45 ACP and 40 S&W race guns. It’s just the perfect burning speed to feed the compensators with a higher volume of gas. With AutoComp competitors get off faster shots with minimal muzzle flash.

Ramshot Silhouette
Choice for competitive shooters in IPSC, IDPA and USPSA. A double-base high performance powder, it’s is an excellent choice for 9mm, 38 Super, 40 S&W and 45 ACP. It has a low flash signature, high velocity, and clean burning properties which also make it the perfect choice for indoor ranges and law enforcement applications.

Ideal Calibers: 9mm, .38 Super, .357 Sig, 10mm

Alliant Blue Dot
The powder of choice for magnum lead shotshell loads 10, 12, 16 and 20 gauge. Doubles as magnum handgun load.

Principal Purpose: Magnum shotshell loads, 10, 12, 16, 20 and 28 ga.
Secondary Uses: Magnum handgun loads

A very slow burning shotshell and magnum handgun cartridge propellant, this powder has somewhat limited applications. This propellant contains some blue colored identification granulations.

Accurate Arms No. 7
Intermediate burning, double-base, spherical powder suitable for a wide range of handgun calibers. No. 7 is an excellent choice for high performance semi-auto handguns such as the 357 Sig, 38 Super, and 40 S&W.

Introduced in 1983 and developed for .38 Super Auto ammunition. A favorite propellant for IPSC shooters who load the .38 Super Auto. Somewhat more specialized in applications than No. 2 and No. 5, it is well suited to high intensity cartridges, such as .357 Sig. It is a good choice for magnum handgun cartridges (such as .357, .41 and .44 magnum) when slightly less than full power loads are preferred.

Hodgdon LongShot
This spherical powder is the most versatile shotshell heavy field propellant Hodgdon has ever produced. Great loads in 10 ga., 12 ga., 16 ga., 20 ga., and 28 ga. are shown in Hodgdon’s Reloading Data Center. This propellant provides true magnum velocities with superb patterns. In addition, LONGSHOT is the best choice for those competitors shooting games such as "Buddy", "Annie Oakleys" and more.

LONGSHOT makes it possible to make USPSA Major with the 38 Super and it produces Major loads in the 40 S&W and 357 SIG at lower than usual operating pressures.

Alliant 2400
Legendary for its performance in .44 magnum and other magnum pistol loads. Originally developed for the .22 Hornet, it's also the shooter's choice for .410 bore.

Principal Purpose: Magnum handgun loads
Secondary Uses: .22 Hornet and 218 Bee

This double base powder has a fine granulation and is suitable for a limited number of small cased rifle cartridges such as the 22 Hornet. It is also popular as a magnum pistol powder. After 60 years of use its applications remain limited but effective. It is often used as a cast bullet rifle cartridge propellant. For the 357, 41 and 44 Magnums it may be the premier selection for full power loads.

Ramshot Enforcer
Best choice for high performance, full power loads in magnum handgun cartridges. It is ideally suited for the 44 Magnum, 454 Casull, 460 S&W, and the 500 S&W. It’s is a double-base spherical powder with excellent metering qualities that meets the performance expectations of serious magnum handgun shooters.

Enforcer's high bulk density contributes to a full case capacity and more consistent loads. Enforcer also performs well in some small rifle cases such as the .22 Hornet.

Ideal Calibers: .357 Mag, .44 Mag, 454 Casull, 480 Ruger

Accurate Arms No. 9

Double-base, spherical powder that is ideal for high power loads in traditional magnums such as the 357 Mag, 41 Rem Mag and 44 Rem Mag. It is particularly well suited to the 357 Sig and 10mm Auto, providing high velocities and excellent case-fill. No. 9 can also be used with large magnums such as the 460 S&W and 500 S&W.

Accurate Arms 4100
Double-base, slow burning spherical powder with exceptional metering characteristics. 4100 is an excellent choice for high performance, full power loads in magnum handgun cartridges. It is ideally suited for the 357 Mag, 41 Mag, 44 Mag, 454 Casull, 460 S&W and the 500 S&W.

Winchester 296
This propellant was developed for Winchester factory-loaded ammunition for 357 Magnum, 444 Magnum, and 410 Bore. Its high loading density provides optimal velocity. 296 is recommended by Winchester for 410 Bore AA loads.

IMR SR 4759
This bulky handgun powder works great in the magnums, but really shines as a reduced load propellant for rifle cartridges. It's large grain size gives good loading density for reduced loads, enhancing velocity uniformity.

This single base powder is suitable for some small case rifle cartridges and a few heavy handgun cartridge loads. In the past its popularity waned so much that it was withdrawn from the market. After being re-introduced it became very popular with cast bullet shooters. SR4759 is the slowest burning of the canister SR series of powders.

Alliant Power Pro 300-MP (Magnum Pistol)
Smokeless spherical magnum pistol powder. Improved velocity and density for more efficient metering and loading. Maximum velocity and performance in magnum handguns. Enables reloaders to duplicate certain factory loaded ammunition. Density designed for proper cartridge fit

Principal Purpose: Magnum Handgun/Pistol
Secondary Uses: .22 Hornet
 
I thought smokeless powder supplied its own oxygen for combustion ...
It does, but it isn't a perfect ratio of oxygen to fuel. In automotive terms, it runs a little rich. That's good because it would burn excessively hot otherwise. Pressure dictates the oxygen to fuel ratio as well.
 
Curious if there is any way of finding out what powder is in factory loads? My new Kahr .380 (approx. 250 rounds through it) loves Remington but still haven't figured out a 100% reliable load for my reloads.
 
In most cases you, the consumer, cannot get the powder that is used in factory loads.
 
helotaxi said:
In most cases you, the consumer, cannot get the powder that is used in factory loads.

Winchester 296 - http://www.wwpowder.com/pistol.html
This propellant was developed for Winchester factory-loaded ammunition for 357 Magnum, 444 Magnum, and 410 Bore.


Alliant Power Pro™ 300-MP (Magnum Pistol) - http://www.alliantpowder.com/products/powder/power_pro_300.aspx
Enables reloaders to duplicate certain factory loaded ammunition
 
"Was developed for" and "enables to duplicate" are not the same as "same as used in". And two examples is hardly other than "most". Most canister powders are not available to the consumer.
 
Most canister powders are not available to the consumer.

Except as pull down powders.

Otherwise they are blended for uniformity to ensure that lot to lot variation in performance remains within an acceptable +/- range of deviation.

And some "Cannnister Powders" are available directly.....Leverevolution is one of them.
 
It does, but it isn't a perfect ratio of oxygen to fuel. In automotive terms, it runs a little rich.

Some are a little rich, some a little lean. The deterrents are also part of the fuel equation that many people forget to add in and consider. Rosin, polyester, and graphite are common deterrents used in powder manufacture...they burn therefore they are fuel. Given the right time under pressure they burn up, not enough time or pressure they don't and become fouling.
 
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