High nitro content vs low nitro content

[bhn22]

I've been wanting to work more with low nitroglycerin powders, but am having difficulty identifying which powders are high in nitroglycerin and which are low. The manufacturers seem to skip over this little tidbit of information for some reason. How do I find this information?

[Houndog]

I can't tell you about each powder individually but Winchester and Alliant powders are double based (contain Nitro) for sure. All IMR powders EXCEPT 700X are single based (NO Nitro) Sorry I can't be any more helpful than that. I SURE wish Rocky Raab was still around when we have questions like this!

[bhn22]

I know where he is. I'll ask him.

[KYCaster]

Be sure to let us know what you find.

Jerry

[NuJudge]

I've read that the manufacturers are trying to reduce the amount of nitroglycerine in powders by reformulating them. Bullseye has always had the reputation of being highest in Nitroglycerine. Looking at its MSDS, it says 4.0-40%. Looking at the Alliant on line reloading guide, they say 40%. The guide also says the following:


Smokeless sporting propellants are of two basic types – single-base and double-base. Single-base propellants derive their energy from nitrocellulose and double-base from a combination of nitrocellulose and nitroglycerin. Alliant propellants range from the “near” single-base American Select (2% nitroglycerin) to the high nitroglycerin (40%) double-base Bullseye. In addition, our propellants contain stabilizers for long storage life and various other ballistic modifiers which reduce flash, improve combustion efficiency, and promote clean burning.

[rsrocket1]

VihtaVuori powders are single based (and very expensive) as what Houndog said about IMR powders. The best hint is to look at the MSDS and look for the absence of nitroglycerine. As you've seen, manufacturers are reluctant to give exact percentages.

You didn't say whether you are looking for handgun/shotshell or rifle powder. Many rifle powders are single based.

[lylejb]

I've been wanting to work more with low nitroglycerin powders

May i ask why?

As long as it produces the results on target I want, I don't really care what's in it.

[Houndog]

May i ask why?

As long as it produces the results on target I want, I don't really care what's in it.

Lyle,
There's three reasons IN MY OPINION for using single based powders over a double based one IN HIGH PRESSURE ROUNDS. The first being single based powders tend to burn cooler so barrels tend to last longer, second, their pressure curves tend to be more linear ( not as many sudden pressure spikes) and the fowling tends to be less as well as softer. Please note I said tend! There are exceptions to every rule and each individual chambering can be different! For evidence for the statements above, look into early 5.56 military ammunition (early Vietnam era) from using ball propellants (allmost all have some Nitro content) and such barrel burners such as the 220 Swift and 22/250. All three of these operate above 55K PSI.

[singleshot]

Hmmm, for some strange reason, I've had some of the best success with high Nitro-glycerin content. Titegroup has been one of my go-to powders in almost everything, and has a good reputation, along with Bullseye for shooting cast well. A few other cast-boolit standouts, IMR SR series powders, also have high NG content.

Houndog, do I gather from your last post that you're primarily concerned with rifles? I use more IMR 7383 than anything else in my rifle applications.

[felix]

Only the named 700X and 800X have nitroglycerine in the IMR lineup for handloaders. Guaranteed! ... felix

[felix]

As you've seen, manufacturers are reluctant to give exact percentages.

They cannot because each CANISTER lot has a specific CLOSE range in tolerance. The feeds used to make the powder is too variable, and various adjustments are made to make ends meet. VV powders seem to have the best luck in lot to lot of all the CANISTER powders I have ever used. No guarantee, but their location provides for a very consistent alder tree growth from which they produce the required cellulose consistency for nitric acid adsorption. ... felix

[singleshot]

Only the named 700X and 800X have nitroglycerine in the IMR lineup for handloaders. Guaranteed! ... felix

Felix, are you saying SR7625 and SR4756 have no nitroglycerine? The search function isn't working right now, but I remember an in-depth discussion on this between 6 mo. and 1 year ago.

[felix]

The early British smokeless powders (called Cordite mostly) and the Hercules Hi-Vel series had 40 percent or more nitroglycerin. That component has been reduced to a maximum of 30 percent for most "high-performance" powders today. Double based fast burning pistol powders are between 15 and 25 percent as reported using after-the-fact analysis. Rifle powders seldom exceed 10 percent because of the amount of powder used per round, keeping heat production reasonably low. ... felix

[felix]

SS, the discussion was in error. I'm sorry I was not involved to help clean up the matter. I just did not see the posts. ... felix

[singleshot]

Also, why are manufacturers trying to eliminate nitroglycerine? Stability?

[felix]

Yes, and prolly for manufacturing insurance costs as well. BlackPowder appears as cost prohibitive as for making nitroglycerin, and has for all essential purposes is now produced in foreign countries more exclusively. Making ball powder seems to be safer all around, including its start to finish production schedule, and with its eventual final storage no matter where and how. Besides, there are other chemicals besides the norm which are now included to make powders safer and more consistent per weather conditions, shooting or not. ... felix

[andrew375]

First off the addition of NG to a powder does not in itself result in it "burning hotter" whatever that means in this case. In fact one of the attractions of the high NG content of cordites for the British was that it was found to result in less heat in the barrels, this was observed mainly in artillary though. The erosion issue with cordite and other high NG content propellents is to do with the fact that they divolve into an oxygen rich gas mixture, that is all the fuel is burned before it runs out of oxygen. This leads to the surplus oxygen attaching itself to the iron of the barrel, so converting the barrel surface to iron oxide (aka rust), this is very brittle and becomes detached when following rounds are fired, exposing a fresh surface for the oxygen to attach itself. This is a heat driven reaction so that is why the erosion starts at the chamber end and rarely progresses further than a few inches up the barrel.

With modern double base powders NG content is kept down way below Cordite levels so there is little, if any, surplus oxygen.

Single base powders devolve in to an oxygen poor gas mix, as a result the nitrogen attaches itself to the barrel surface to form a different inter-metallic compound, this time iron nitride and erosion progresses as above only less so due to the lower reactivity of nitrogen. The oxygen poor nature of the gasses is also responsible for muzzle flash as the hot carbon monoxide reacts with oxygen in the atmosphere at the muzzle.

It has been shown (by Bob Greenleaf amongst overs) that barrel throat wear in such rounds as the .220 Swift is principaly down to chamber design.

The problems encountered with the use of ball powder in early batches of .223 ammo by the u.s. military was to do with inadequate control of the amount of calcium carbonate added to neutralise acid used during the manufacturing process. A problem that was known about from the Korean war and about which Eugene Stoner warned about during acceptence trials for the M16. Barrel wear was due to the, now well known, issue of lack of guidence on cleaning, which in the heat and humidity of Vietnam was fatal to any barrel. The cure was to chrome line the chamber and throat. Powder manufacturers also learnt their lesson to reduce the calcium carbonate used to just enough to do the job and the wash the powder more thoroughly.

BTW, the reason why Chrome and Stellite plating reduces erosion is due to the fact that neither will react to oxygen or nitrogen.

[felix]

Excellent, Andrew! ... felix

[prs]

MOST EXCELLENT. Thank you.

prs

[uscra112]

Well, Andrew said it much better, but my comment was going to be that, Boyles Law being what it is, the "temperature" at any given pressure would be independent of the nitro content.

[Old Dawg]

IIRC the military said the fouling in the .223 ammo was due to calcium carbonate having been added to reduce the Ph, not because of nitro.

[Eutectic]

Felix, are you saying SR7625 and SR4756 have no nitroglycerine?

Yes.... They are both single base. SR7625 is porous base as well.

Eutectic

[cowboybart]

What about the Scot or Brigadeer powders?? Weren't they Nitro-cotton or something like that??

[fatnhappy]

Only the named 700X and 800X have nitroglycerine in the IMR lineup for handloaders. Guaranteed! ... felix

That's good to know Felix. I was laboring under the misconception the entire IMR line was single base.

[madsenshooter]

Well, Andrew said it much better, but my comment was going to be that, Boyles Law being what it is, the "temperature" at any given pressure would be independent of the nitro content.

Have you ever noticed the color of the neck of your Blue Dot rounds? They almost, but not quite, appear annealed from the high nitro content. Temperature of the burn or oxides as Andrew explained? I don't see it with 4227, 4198, or other powders, including double based ball, just with high nitro powders I've used, Blue Dot and 10B101.

[frugal]

So can we extrapolate that 10B101 and blue dot are more erosive to throats than single base powders or is the higher heat compensated for by the lower pressure of a cast bullet load? I also have noticed that 10B101 gives a blue hue to brass necks

[ddixie884]

Great info, I am continually impressed with the knowledge present on this forum!

[madsenshooter]

So can we extrapolate that 10B101 and blue dot are more erosive to throats than single base powders or is the higher heat compensated for by the lower pressure of a cast bullet load? I also have noticed that 10B101 gives a blue hue to brass necks

I once used what had to have been a new Krag barrel with Blue Dot loads, a 123gr .310 V-Max bullet going 2400-2500fps. After only a couple matches and some practice rounds, perhaps 300 rounds, I could no longer seat the little bullet out to touch the rifling like it did when I first started. Maybe I could have, but then I'd have been over magazine length, as it was close to max magazine length to begin with. Original Krag barrels are a bit softer than today's barrel steel though. Yet another reason I should get a new Critierion barrel.

[uscra112]

I don't remember any of my case necks coming out blue, but my loads from last summer were not as hot as what you just posted.

Just been reading the Harvey Donaldson book. He claimed that he'd fired 10,000+ rounds through a .220 Swift with no loss of accuracy, by using colloidal graphite wads. I know these have been either ignored or discredited in recent years, but was there something to it? Or was he just blowing smoke?

Maybe the carbon was titrating the oxygen?

Phil