Progressive POWDERS for Pistol

[Bringsteen]

I am curious about using progressive powders in pistols, i.e., powders that have a slower burn rate when they are ignited than when they are about to be fully burned. The advantage of progressive powder is that the max pressure occurs after the projectile has "gotten up to speed," so you can get higher velocity within a given maximum pressure. Progressive powders are available in slower rifle grades (such as the Vihtavuori 500 series) but they don't seem to be available in faster pistol grades from any company. Am I wrong? Does anyone have experience using progressive powders?

 

[Galil5.56]

By their nature smokeless propellants are just that, propellants, not explosives and progressive burning achieving a certain pressure curve according to conditions. Even Bullseye is very progressive compared to an actual explosive.

You can make a propellant act like a bomb (pipe bomb) if you confine it enough to make it explode. True explosives need no confinement, and have an explosive velocity many times above 20,000 fps.

Apples and oranges as far as us reloaders are concerned.

 

[Jim Watson]

The powders commonly described as "slow burning" relative to handgun applications are really of progressive burning formulation. It is just that it cannot be carried nearly as far as in a rifle because of the shorter barrels and smaller case volumes. See Vihtavuori N110 versus N320 for .357 Magnum as an example. The more progressive ("slower") N110 delivers about 350 fps higher velocity. Largely because its burning characteristics allow the use of a good deal more powder without exceeding maximum chamber pressure.

 

[moooose102]

i think it would be great if they could develop a self regulating powder. one that below a certain pressure would keep inceasing in burn rate, and above a certain pressure would slow down. if developed properly, you could get max velocity out of every load with no over presure dangers. just fill it to case capcity, seat the bullet, and forget it. probably in the next 30-40 years or so. OBVIOUSLY I KNOW NOTHING ABOUT CHEMICAL COMPOSITIONS OR REACTIONS!!!!! but it would be nice.

 

[Bringsteen]

It would be nice to have a self-regulating powder. I would like to see just one progressive pistol powder, though. Progressive rifle powders have improved ballistics for a number of cartridges. With a relatively fast progressive, you could potentially load a pistol cartridge up to its psi limit and get a bit more velocity.

 

[Jim Watson]

Whassamatter, Bringsteen, you don't believe me?
Pistol powders suitable for high velocity and magnum loads ARE progressive burning, within the limits of the barrel length and case volume.

Don't hold your breath, mooose. A "self regulating" powder runs against what they teach in physical chemistry. You CAN load ammunition with a fill-it-and-forget-it approach, though. With black powder.

 

[snuffy]

Progressive??¿

I've never heard of the term you're referring to. Are you coining a new one? Progressive is what some presses are called, meaning a progression of steps being performed to complete loading of a shell.

As pointed out, smokeless powder burns at a given rate depending on it's composition and it's degree of confinement. Deterrents are added, or coated on the outside to delay burning until pressure has built enough to overcome the deterrents. Size, and shape of the individual granuals also controls burn rate and density. Powders made to take up space in older black powder cartridges are hollow sticks,(IMR 4759, AA-5744), or shaped like the new IMR trail boss, looks like little doughnuts or cheerios.

Calling smokeless "progressive" is correct in that in a 100% density load, the powder burns progressively from the rear to the front. The rate of burn is controlled by the factors listed above.

 

[Bringsteen]

Jim Watson,

I do believe you. I don't think that I read your first entry correctly. Sorry about that. Jim, I shoot 10mm in a Colt Gold Cup 1911. Using a 180 grain jacketed bullet, what powder do you think I should use to achieve the maximum velocity while staying within the 37,500 psi limit?

Snuffy,

I am using the term "progressive powder" in the sense used in "Understanding Firearm Ballistics" by Robert A. Rinker. This is a great resource.

 

[snuffy]

Okay, a search on amazon brought this review of Mr. Rinker"s book.

By J. M. Nelson
"Rinker's book is well organized and documented, but a difficult read because of sentence and paragraph structure, run-on sentences, poor use of commas, nonparallel construction, illogical and vague antecedents, wordiness, and contradictory statements. It also contains several, significant mathematical errors and incomplete descriptions, and it is occasionally condescending. In addition, the intended audience seems in flux. Such a definitive work in its 4th edition deserves better focus, editing and proofing.

Notes from my reading indicated over fifty errors, including at least 9 errors in logic, 7 mathematical errors, and 37 grammatical errors. I assume that these are only representative of what a closer reading would reveal."

I think I'll pass on getting for it now. Maybe in 4 years when I retire, I'll have time to read it. It's interesting he calls it progressive burning. Maybe he was trying to "coin a new phrase"?

 

[Jim Watson]

I doubt it.
In 1937 Phil Sharpe used the term "progressive" in reference to the DuPont Improved Military Rifle powders which came out in 1915. I haven't had his Complete Guide to Handloading very long, I got acquainted with the term in the NRA Handloader's Guide of 1969 and in Hatcher's Notebook.

Sorry, Bringsteen, I don't load 10mm. A search of the loading manuals for the highest velocity load will be all that is required to select a powder, they will not publish a load above the maximum chamber pressure.

 

[Bringsteen]

Snuffy,

I am using the 6th edition of Understanding Firearm Ballistics, copyright 2005. Some wordiness and awkward sentence constructions remain, but otherwise it is a mathematically and scientifically sound reference work.

 

[redneck2]

Mike McNett used to list a lot of loads in the 10mm forum on GlockTalk.

It's difficult to get too much Blue Dot or 800-X under a 180. You run out of space before reaching max. Before you load, read his stuff first. I use Blue Dot with 180 Speer Gold Dots and get no case bulge with my stock G-20. This probably achieves what you're looking for.

 

[Bringsteen]

Thanks Redneck. I am often impressed by the durability of 10mm brass. Most of my 10mm reloads are "target strength" and all are shot out of a Colt 1911. But I have friends and relatives who load hot stuff for their g-20's with no difficulties, and my dad loads really hot stuff for his S&W 610 with no adverse effects. I think you and Jim Watson answered my central question, but I am still on the lookout for the "perfect" powder that will let me break 1400 fps with 180 grain bullets, without popping primers or turning my brass into one-time, no reload throwaways.

 

[brickeyee]

"You can make a propellant act like a bomb (pipe bomb) if you confine it enough to make it explode."

Smokeless powder can create a bursting fracture of a container from high pressure, but it will not detonate and produce actual shock waves (a defining characteristic of an explosive).

If you made a pipe bomb from smokeless it would act like an over pressurized gas cylinder. Some fracture will occur, but nothing like using black powder.
With black powder the shock wave breaks up most of the pipe and sends it outward as small pieces of shrapnel.