What are the units??
Powder burn rate chart
- Thread starter Gavin-in-Utah
- Start date
Here is one from Norma https://www.norma-ammunition.com/en-us/reloading-data
scroll towards the bottom. It gives both relative velocity and relative pressure.
scroll towards the bottom. It gives both relative velocity and relative pressure.
Sorry, I edited my OP to add - the Ba is the burn rate.
Lone Hunter
Silver $$ Contributor
Dave M.: To be honest I don’t know what units are. I knew that Ba is the burn rate.
Murray Brook
Silver $$ Contributor
In Quickload you can adjust your Ba factor a certain amount to adjust the velocity given in the program to match the actual chronographed velocity. Like making up for lot to lot variation . After the adjustment the velocity #'s given by the program will match up better with that lot of powder in that cartridge.
VA_XTC_Shooter
Silver $$ Contributor
All of the charts provided in this thread are different. Why is that? Are powder makers that secretive about their powder we can't get accurate burn rates to compare?
RegionRat
Gold $$ Contributor
Keep in mind that "Ba" and "Burn Rate" are over simplifications for a basic model.
If you do a caloric bomb test, you are placing the material in a vessel and igniting it while you measure temperature and pressure against time. When we do standardized testing, we get "standardized" results. I placed quote marks around that because when you then take those propellants and put them in cartridges of different sizes, with bullets of different diameters and resistance, you may get a different answer for the same powder just due to context.
Unless you are directly trying to calculate a moon shot where you cannot test or "take sighters", don't worry about it too much... YMMV
I had gathered up 6 charts that I had found online prior to '19. As mentioned - none were alike, necessarily equal in number of powders or gave a specific powder the same 'valuation' within the individual sample.
I still find the attached the easiest to make quick use of at a glance.
Last edited:
Gavin-in-Utah
Silver $$ Contributor
Thank you. I will update my copy.
Gavin, that's the most complete burn rate chart I've seen. Thanks for your work on it.
One very small observation; In this burn rate chart and all others I've seen, Alliant Re26 appears well below (slower than) Re25. Perhaps folks are slotting them according to their numbers, with 26 > 25, and, in the Alliant lineup, larger numbers mean slower powders. Since these are powders that interest me with my cartridges (.270 Win., 7 mags), I've experimented with QuickLoad with them, and Re 25 consistently comes out (via QuickLoad) as slower than Re26, in the sense that a larger charge weight of Re25 is indicated for a given pressure than is indicated for Re26 at the same pressure.
One very small observation; In this burn rate chart and all others I've seen, Alliant Re26 appears well below (slower than) Re25. Perhaps folks are slotting them according to their numbers, with 26 > 25, and, in the Alliant lineup, larger numbers mean slower powders. Since these are powders that interest me with my cartridges (.270 Win., 7 mags), I've experimented with QuickLoad with them, and Re 25 consistently comes out (via QuickLoad) as slower than Re26, in the sense that a larger charge weight of Re25 is indicated for a given pressure than is indicated for Re26 at the same pressure.
Murray Brook
Silver $$ Contributor
I have used RL-26 in several cartridges that I had also used RL-25 in and every time I found RL-25 to be appx 2-3 grs slower than RL-26. On the same subject I used RL-23 in my 25/06 and 257 Weatherby and found it to be faster than RL-22. JME
I have yet to see any chart incorporate Nitro 100 NF. From what I've seen and experienced, it should be ~1-2 on the chart.
Lone Hunter
Silver $$ Contributor
Lost at RedfootRanch’s post #31 …. His chart shows it under Accurate Powder. It doesn’t show NF after the Nitro 100 but I think that is what you are talking about.
That's the OLD Nitro (non- New Formula). The NF has been out for 12 years...and I've only ever seen it listed in one chart. It just shows how out of date a lot of the information actually is.
Lone Hunter
Silver $$ Contributor
If you find an up to date chart post it. I don’t think any of the charts have been updated in several years. The guys that posted in this thread were trying to do that. With all the new powders and discontinued powders I would think it would be hard to keep up to date. There were some post in the daily bulletin about burn rate charts a little while back.
dhagerty40
Gold $$ Contributor
Not sure if anybody knows, But Hodgon just updated their burn rate chart this month:
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.