The thread "Does brass make a difference?" got me thinking.

How consistent is a certain make of powder from one lot to another?

i.e. I worked up a fairly accurate load using Win296. I am about to run out of this container of Win296. I have another container of Win296. What is the likely hood of me keeping my standard load.

Making powder is organic chemistry so any batch may or may not vary from others. Our powder, called "cannister", burns within narrow limits of a specified point and any that fall within those limits can be sold to us.

We don't know what those burn limits are 'cause "they" ain't saying, but it doesn't vary much from lot to lot and it can be identical. Depending on the variation and capacity of the cartridges I doubt we will find a variation exceeding the burn equivelant of more than .2 or .3 grains. That means that for sane loads we can pretty much ignore it.

Powder varies quite a bit between lots.

Powder, like chocolate cakes, may be organic chemistry, but there are a lot of variables in the making of both.

Powder manufacturers blend different lots of the same powder to achieve a consistent product which they can sell to the public.

When I called Accurate Arms, they told me they blended their powders to a tolerance of 5%, then they said the industry norm was 10%.

Which was a claim that I always found to be very strange. For years Accurate Arms bought powder from anyone. You had Chinese powder, Czech powder, probably others. And while they may have blended the stuff to a 5% tolerance, I found that each and every different lot of Accurate Arms powder was different from the last.

I would duplicate loads, and find I was blowing primers.

Which tells me there is something more than just blending that needs to be kept track of.

I heard that now AA is trying to stay with only a few powder makers, so this should keep the end product more consistent.

A Champion long range shooter I know swears by Vihtavuori powders. He claims that it is the most consistent brand of powder out there.

If you are working with a maximum load, changing lots of the same brand of powder can do strange things to your primers.

Unless you are a shoot them all thru the same hole kinda shooter, don't worry about it. Make sure the stuff in the new can looks like the stuff in the old can and keep on reloading. I, and a great number of the more experienced reloaders routinely will add the dregs of the old container of powder to the new container, tumble it about in our hands for a moment, and continue reloading.
The day to day changes in temperature and humidity to say nothing about wind will have a greater impact on your POI than any change between lots of powder.
We are blest with the consistancy of our components.

Powder is manufactured according to Specs , when not meeting certain strict criteria , it's reformulated into another burn ratio up or down depending on where it's burn test falls .
It can also be Bulk hopped for military purposes .

When I worked for Hercules Powder division NOTHING went out the door over 3% one way or the other .

There's a 3/2/5 rule . Powder 3% , Primer 2% which equals a total of 5% . This is an unwritten standard for all reloading components equations Pressure MV ME calculations .

How ever take notice it has been my personal observation that some of my " Very Best Groups " have been with MV Chrony measured deviations averages of 7 - 105 FPS for # 15 rounds .

This makes BR shooters almost sick when hearing this kind of talk .

Shoot Straight Know Your Target . ...

Look in your manuals at the difference between the data for W296 and H110 with the same bullet. They are different lots of the same powder. Hodgdon buys a lot and puts a H110 sticker on it and Winchester puts a W296 sticker on another batch.

Some powders tend to vary more than others, depending on the manufacturer's standards and perhaps the method of manufacture.

You asked specifically about WW 296. It is a ball powder made in the St. Marks, Florida facility. Generally speaking, the methodology used in this plant makes larger lots and it is easier to keep each lot closer to specs. There are some variations, but I find ball powders from this facility to be among the most consistent in burning qualities. They may or may not do well in a particular load, but they are pretty consistent.

The Alliant Reloader series (most of them, anyway) and Norma powders are made by Bofors of Sweden and are double-base powders with some nitroglycerine content. These powders have a reputation for somewhat wider variations from lot to lot than most powders. I do not know whether this a result of the method of manufacture or simply wider tolerances in the specifications.

Many of the Hodgdon powders with the same numbers have come from multiple sources. For instance, the original H-4895 was G.I. surplus. It was replaced by a powder manufactured by Nobel in Scotland, which was in turn replaced by a powder manufactured by ADI in Australia. Uncannily, all of these very different powders have behaved pretty much the same through the years, despite being separated in origin by 60 years and three continents.

The bottom line is that powders can and will vary an unknown degree from lot to lot, sometimes significantly and sometimes not. If you find a load which works particularly well in a gun, it is a wise thing to acquire a sufficient amount of powder of a single lot to last you for a signficant period of time.

I have found that powder lots can vary as much as +/-5%.

quote:

Originally posted by Ol` Joe:
Look in your manuals at the difference between the data for W296 and H110 with the same bullet. They are different lots of the same powder. Hodgdon buys a lot and puts a H110 sticker on it and Winchester puts a W296 sticker on another batch.

In loading H-110 and W296 in my 22 Hornet, I got far different accuracy between the two.

Don

quote:

Originally posted by DMB:

quote:

Originally posted by Ol` Joe:
Look in your manuals at the difference between the data for W296 and H110 with the same bullet. They are different lots of the same powder. Hodgdon buys a lot and puts a H110 sticker on it and Winchester puts a W296 sticker on another batch.

In loading H-110 and W296 in my 22 Hornet, I got far different accuracy between the two.

Don

Pg 16 June/July Handloader mag has a write upon W296.
Hodgdon has used Win ball powders for years. HP38 is W231, H414= W760, ect.......

Sorry to ask a stupid question, but 5% (or 10%) of what? Energy by weight? Energy by volume? Amount of nitrocellulose? To me, the number 5% doesn't mean anything without qualifying it.

Wink: I agree with you, but at least talking in "percentages" in regard to powders seems a bit more meaningful than "percentages" in used guns. Percent of what, I've always wanted to know?

Regarding H110 and 296 being the same powder, I had heard that Winchester and Hodgdon got the same base powder stock from the St. Marks plant but that they did the final blending and the application of deterrent coatings at their own plants prior to packaging it. This would produce very similar but slightly different powders.

If they were the same powder I would expect that the maximum charges for both would be the same when tested by someone using the same bullet and brass during their tests. I was starting to work up some loads for my 41 Mag using H110 and I researched a number of magazine articles as well as various reloading manuals. Looking at 210 grain bullets the H110 had the higher maximum charges 6 times as compared with 296 which had the higher maximum charge once. If the variance was due to normal manufacturing tolerances and batch to batch differences I would expect that each would have the higher maximum about the same number of times. So I concluded that these were not identical powders. Now this was before Hodgdon took over the distribution of Winchester powder so things may have changed and, since the Hodgdon annual now shows the same starting and max loads for both powders, probably have. When I use up my old H110 and go to the newer powder I will retest to see what the differences are.

Can any of you confirm or refute what I heard about there being differences in the final processing of H110 and 296?

I cannot comment specifically on the powder you are using. However, I have found that powders from one manufacturer can be very much the same from lot to lot, and from other makers, quite a variance will exist. From some makers, it may even be wise to rework up any loads that were satisfactory in the past. This is wise practice anyway,. if your loads are at or near maximum levels.

Over many years, I have found that IMR 3031, IMR 4895, and IMR 4350 seem practically identical to the same powders made many years previously.

However, I recall an instance in which a company COULD NOT DUPLICATE THE EXCEPTIONAL PERFORMANCE OF ONE LOT OF THEIR POWDER, and dropped that powder from their lineup because of this, substituting a "different" powder for the one they dropped. The powder in question was a specific lot of Norma N205. This lot produced significantly higher muzzle velocities at acceptable pressures than other powders, including previous and subsequent lots of N205. Something was different about that one lot, and I don't believe Noram ever discovered the cause. If they did, they never made a public announcement. The "new" powder was Norma MRP (now MRP1, I believe). Suffice it to say, there has been no duplicate of that one lot of "super N205" to this day!

With regard to lot to lot uniformity of today's canister grade propellants, "consistent" is not a word I would use. Some do seem to be more consistent between lots than others, but I've never found two lots of the same powder that really were the same. With so many people loading for single barrel rifles and not using chronographs today, I think most folks just don't notice the difference, even though its usually there. I shoot mostly doubles, and their regulation is sensitive to changes in velocity. Once you find a load that produces standard velocity with perfect regulation in a given rifle, changing lots of the same powder usually requires working back up to the same velocity with the same bullet, or regulation suffers. This is where you really notice the density variation between lots of the same powder.

quote:

Originally posted by El Deguello:
Over many years, I have found that IMR 3031, IMR 4895, and IMR 4350 seem practically identical to the same powders made many years previously.

With respect to IMR 4350, that statement blows me away. Lot to lot, IMR 4350 is the most inconsistent I've ever found.

I have one rifle that loves IMR 4350, a .400/.360 Nitro Express double. Back when I first got it, it showed a clear preference for IMR 4350. When the first lot ran low, I bought three cans of a new lot, and loaded a batch using the same charge as I had with the old. At the range, I fired two pair over the chronograph with my old load, which was extremely accurate, and velocity was precisely where it had been before. I then fired two pair with the new lot. Amazed, I fired four more. With all other components the same, with the same charge of two different lots of 4350, fired back to back in the same rifle, the new lot averaged 200 fps slower than the old, and the barrels printed very wide. The 1" group I was used to went to 4". The individual barrel groups were very small as always, but wide of each other, which confirmed what the chronograph said. With the old lot, I was using 51.5 grains with Fed 210s, RWS cases, and Barnes 300 grain Original jacketed spitzers. Working back up with the new lot of powder, I had to go to 56.5 grains to obtain the same velocity and regulation. That was 17 years ago. Since then with subsequent lots, the load has bounced around from 51.5 to 57 grains to get the same velocity and regulation. The least I've had to adjust between lots was 3 grains.

In other doubles, Alliant Reloder 15 seems more consistent between lots than most, but I've never found two lots that shot the same without some adjustment. Loading manuals insist that you reduce and work back up when changing lots of powder, and they're right.
-----------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

WW296 and Hodgdon H110 are, according to Mr. Hodgdon himself, the same powder and completely interchangable. And now that Hodgdon is selling both you can bet that one of them is going to go. I hope it is the Winchester product simply because of what the name implies to me. 5% vairation in grains of powder to achieve the same pressure in the same loading is what that variation is. If you are loading 16 grains in a 357 Mag then that means that you should drop your charge .8 grains and work it back up to not more than 16.8 grains to regain the same load that you were shooting before. That has never been a big deal for me because I buy the stuff in kegs - not in one pound containers.
The more powder that you use in any given cartridge means that you have to drop that much more in your charge and work back up. This rule applies to all powders and for all of your loads. Anytime you buy a new lot you need to do this to assure yourself that you are getting the same pressure and accuracy from your load.

Stonecreek wrote:

quote:

The bottom line is that powders can and will vary an unknown degree from lot to lot, sometimes significantly and sometimes not. If you find a load which works particularly well in a gun, it is a wise thing to acquire a sufficient amount of powder of a single lot to last you for a signficant period of time.

Well said...

Of the various powders I use in quantities worth speaking of, the 2 most consistent for me have been H335 and N160.

I have one particular rifle in which I've used H335 in since around 1988. I changed the load once -- dropping from 27.5 to 27 grains under an 80 grain Sierra SSP bullet in a 6mm-.223. That change took place in 1997.

Today, the same load still produces the same velocity and accuracy. That's tough to beat.

As to N160 and a couple other Vihtavuori powder that I've used to a lesser extent, the degree of consistency from lot to lot has been amazing in the 3+ years I have been using them.

I also use quite a bit of Re-22 and Re-15. Changes from lot-to-lot are more easily detectable with these propellants, but the accuracy across the board has always been outstanding. And if you heed Stonecreek's advice, those minimal variations will be irrelevant.