Note that ALL of this info was gathered from several long articles in my 1981 NRA book of HANDLOADING. Good articles; good book. Some of this material is also directed toward rifle loads and forum members should be aware of this fact.
Reduced Loads article by WM. C. Davis, JR.
Powders suitable for full-charge loads are usually of large granulation and have deterrent coating on the grain's outer surface to achieve better velocity-pressure relationships in max loads.
Since smokeless powder burns at a rate which is strongly dependent on pressure, reduced loads which use powders suitable for full-charge loads often do not burn completely and produce poor results. Using powders of finer granulation, designed for faster burning, result in more consistent loads. "Minimum loads in rifles and handguns require the use of lubricated lead bullets and fast-burning pistol or shotgun powders."
Using rifle cartridges with large powder capacity and small-diameter bullets, less than .35 caliber, require special caution with reduced loads.
"For reasons not completely understood, reduced loads of slow-burning deterrent-coated powders in such rifle cartridges will, on rare occasions, develop destructively excessive chamber pressures when fired." However, the author then notes that Hercules ran exhaustive tests with severely reduced loads in rifles, using slow-burning powders, and was unable to blow up any rifles, despite the most severe tests that could be conceived. This led to rather convincing evidence that such blowups were more likely the result of double charges of powder.
For Handguns only:
Two basic things to watch out for in assembling loads with reduced or light powder charges. Certainly, the first is to be aware of the danger of double or multiple charges. The second point is to avoid the use of jacketed bullets. Use only lubricated cast bullets due to their greatly decreased friction in traveling down the bore.
"WW296 is a handgun powder that should be used in the charges which are specifically recommended and never in reduced loads." And we are also familiar with H110 having specific caveats against using reduced loads. Problems associated with the use of these powders may lead (at least) to the primer pressure pushing the bullet into the barrel forcing cone, leaving a large chunk of unburned powder sitting directly behind the bullet.
The author recommends, for full-charge factory loads, such powders as Blue Dot, 2400, SR-4756, IMR-4227, WW 296 or H110. (I am aware that there have been some warnings against using Blue Dot in handgun loads, but I am NOT aware of the specific warnings. Perhaps one of our readers can help out here.)
"Powders for reduced loads should be easily ignited by the primer, burn completely, and be of low bulk density to occupy as much space as possible in the cartridge case." He recommends well-known double-base powders such as Unique and 2400 for easy ignition and (usually) good results. For handgun less-powerful loads in the .357, .41 and .44 Magnum cartridges, suitable powders are Unique, PB, WW 630 and HS 6.
"For light targe loads, using lead bullets, Bullseye, 700X, WW 231, and HP-38 are available."
He notes that a large amount of air space in reduced loads is detrimental to their performance and suggests that one way to solve this problem is by the careful use of fibrous filler materials. There have been problems, however, such as "ring-bulges" occurring with this method.
An alternative procedure, which has often been mentioned by other posters on this site, is to elevate the gun's muzzle just before aiming at the target and firing the shot, thereby assuring that the powder is always positioned at the head of the cartridge case.
The author doesn't always distinguish between powders recommended for handguns versus powders more specifically used in rifles. Use this information at your own risk..or buy the book and make your own determination.
Another related article in this book, MINIMUM LOADS IN HANDGUNS, by William Dresser, stresses the use of normal-weight-for-caliber wadcutters to minimize airspace within the case, as well as the nearly universal use of Bullseye pistol powder due to its ease of ignition. His article concerns using absolute minimum loadings, for "basement" target practice, which is really not the point of my post.
I offer this material as I did find it to be very interesting, and may answer some concerns of forum members. I understand that this information may seem dated (1981) and that more recent information may offer newer or better methods. Please use this material at your own risk.
Sonnytoo
Reduced Loads article by WM. C. Davis, JR.
Powders suitable for full-charge loads are usually of large granulation and have deterrent coating on the grain's outer surface to achieve better velocity-pressure relationships in max loads.
Since smokeless powder burns at a rate which is strongly dependent on pressure, reduced loads which use powders suitable for full-charge loads often do not burn completely and produce poor results. Using powders of finer granulation, designed for faster burning, result in more consistent loads. "Minimum loads in rifles and handguns require the use of lubricated lead bullets and fast-burning pistol or shotgun powders."
Using rifle cartridges with large powder capacity and small-diameter bullets, less than .35 caliber, require special caution with reduced loads.
"For reasons not completely understood, reduced loads of slow-burning deterrent-coated powders in such rifle cartridges will, on rare occasions, develop destructively excessive chamber pressures when fired." However, the author then notes that Hercules ran exhaustive tests with severely reduced loads in rifles, using slow-burning powders, and was unable to blow up any rifles, despite the most severe tests that could be conceived. This led to rather convincing evidence that such blowups were more likely the result of double charges of powder.
For Handguns only:
Two basic things to watch out for in assembling loads with reduced or light powder charges. Certainly, the first is to be aware of the danger of double or multiple charges. The second point is to avoid the use of jacketed bullets. Use only lubricated cast bullets due to their greatly decreased friction in traveling down the bore.
"WW296 is a handgun powder that should be used in the charges which are specifically recommended and never in reduced loads." And we are also familiar with H110 having specific caveats against using reduced loads. Problems associated with the use of these powders may lead (at least) to the primer pressure pushing the bullet into the barrel forcing cone, leaving a large chunk of unburned powder sitting directly behind the bullet.
The author recommends, for full-charge factory loads, such powders as Blue Dot, 2400, SR-4756, IMR-4227, WW 296 or H110. (I am aware that there have been some warnings against using Blue Dot in handgun loads, but I am NOT aware of the specific warnings. Perhaps one of our readers can help out here.)
"Powders for reduced loads should be easily ignited by the primer, burn completely, and be of low bulk density to occupy as much space as possible in the cartridge case." He recommends well-known double-base powders such as Unique and 2400 for easy ignition and (usually) good results. For handgun less-powerful loads in the .357, .41 and .44 Magnum cartridges, suitable powders are Unique, PB, WW 630 and HS 6.
"For light targe loads, using lead bullets, Bullseye, 700X, WW 231, and HP-38 are available."
He notes that a large amount of air space in reduced loads is detrimental to their performance and suggests that one way to solve this problem is by the careful use of fibrous filler materials. There have been problems, however, such as "ring-bulges" occurring with this method.
An alternative procedure, which has often been mentioned by other posters on this site, is to elevate the gun's muzzle just before aiming at the target and firing the shot, thereby assuring that the powder is always positioned at the head of the cartridge case.
The author doesn't always distinguish between powders recommended for handguns versus powders more specifically used in rifles. Use this information at your own risk..or buy the book and make your own determination.
Another related article in this book, MINIMUM LOADS IN HANDGUNS, by William Dresser, stresses the use of normal-weight-for-caliber wadcutters to minimize airspace within the case, as well as the nearly universal use of Bullseye pistol powder due to its ease of ignition. His article concerns using absolute minimum loadings, for "basement" target practice, which is really not the point of my post.
I offer this material as I did find it to be very interesting, and may answer some concerns of forum members. I understand that this information may seem dated (1981) and that more recent information may offer newer or better methods. Please use this material at your own risk.
Sonnytoo
