Dear All,

Are powders IMR4350 and H4350 double or single based??

Could anybody be bothered outlining the differences in composition between double (nitroglycerine?) and single based powders??

Double based powders seem to produce very impressive velocities (on paper, at least), but some people claim such powders are harder on barrels than their single based cousins??

- mike

Single base powders are made from nitrocellulose. Double base powders have a nitrocellulose base with nitroglycerine added to increase the energy per grain of powder.That is why double base powders usually offer some rather impressive velocities.Some of the newer double base powders have some other additives to increase energy as well. IMR & H4350 are single base powders. I am not aware of any credible information that "proves" one is harder on a bore than the other,although there will be lots of opinions on that. Hope that helps.

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I am not aware of any credible information that "proves" one is harder on a bore than the other

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Originally posted by snowman:
.... Hope that helps.

Does indeed, thanks!

- mike

quote:

I am not aware of any credible information that "proves" one is harder on a bore than the other

I use more double base than single. I have seen reports and lip service saying the double is harder on barrels. In my experience I have never seen any difference. I do "believe" the bouble burns a little hotter and heats the barrel quicker. I don't shoot my barrels hotter than I can hold them.

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Originally posted by mho:

quote:

Originally posted by snowman:
.... Hope that helps.

Does indeed, thanks!

- mike

Mike

If you read V/V manuals you will note they use an additive to reduce barrel wear and tear with their double based powders.

I use a lot of V/V powders and have not noticed any undue throat wear in my rifles.

Best wishes, Bill

LAST TIME I CHECKED ALL IMR POWDERS WERE SINGLE BASED.

This is a VERY interesting email I got from Vihtavuori last year:

Dear Mr ......,

We are happy to be able to supply reloading powder for all quality concerned shooters like you.

Bore and throat erosion is really dependent on powder composition. The important parameter is flame temperature, which is unfortunately immeasurable quantity. Based on thermodynamic calculation, and long experience it is well known fact that higher energy content (i.e. heat of explosion) leads to higher flame temperature and higher throat erosion.

Easiest method to improve ballistic performance is to add nitroglycerol in powder composition. These powders are called double base powders. As you have heard, these powders tend to cause more barrel and throat erosion compared to single base powders. This difference is clear but it is, however impossible to quantify as for example as numbers of rounds to reach same erosion level.

All Vihtavuori N100 (N105...), N300 (N310...) powders, 3N37 and 3N38 are single base powders. These products are made with best available raw materials and manufacturing methods to get maximal performance you can get without using more erosive double base composition. Therefore, these Vihtavuori products cause less erosion than most of other competing powders. Especially high nitroglycerol contents (and thus erosion) are used in spherical powders (ball powders) and some US products.

Among Vihtavuori product line we have only five types we call N500 (N530 ... N570) which are by composition double base powders. N500 rifle powders contain small amount of nitroglycerol to add a bit more performance required mainly for extremely long distances. Even with these products we have added a special additive as well kept nitroglycerol content rather low in order to minimize the barrel erosion effect.

So, my opinion and advice is to keep barrel and throat erosion on minimum by using only single base powders like Vihtavuori N100, N300 and 3N.

Best Regards,

Mikko Vuoristo
EURENCO Vihtavuori Oy

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As you have heard, these powders tend to cause more barrel and throat erosion compared to single base powders. This difference is clear but it is, however impossible to quantify as for example as numbers of rounds to reach same erosion level.

I have "heard" it and "read" it often written by single base powder manufactures. If the difference is "clear" I find it hard to understand why someone can't (hasn't) do some actual testing to prove something they feel is so obvious.

" These powders TEND to cause more barrel and throar erosion." The difference is clear but impossible to quantify.
This sounds more like advertising to me than facts.

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This sounds more like advertising to me than facts.

I think they are using deductive reasoning without evidence.

If heat causes wear/erosion, then hotter powders must cause more wear/erosion. This could be true but doesn't necessarily mean it must be true.