which is the faster powder ?

[rebs]

Between Varget and Reloader 15 which is the faster powder ? Loading 69 gr SMK's for a 16" 1/8 twist.
Also loading 77 gr SMK for a 20" 1/9 twist. Which powder for which barrel and bullet weight ?

[HiBC]

There may not be an easy answer.Of course,you can look at a burn chart,but those are taken at one condition.You might get a different answer at 55,000 vs 62,000 psi.

I can tell you that with a 1 in 9 twist 16 in bbl,I got best results with a 69 gr bullet and Varget,but with a 1 in 8 twist 18 in bbl and 75 gr Hornady bullets,the RE-15 outperformed. See Hornady's AR-15 data

[hdwhit]

According to the burn rate chart I have from Hodgdon dated 11/22/2016, RL-15 comes in at 99th fastest while Varget comes in at 101st fastest.

But, if you consult the burn rate chart in the VihtaVuori 2017 Reloading Guide, Varget is listed as being faster than RL-15.

Which one is right? Well, they both are. You see there is no universal protocol for determining a powder's burn rate. Each manufacturer or laboratory uses their own method to generate data based on what they need it for.

Given the close proximity of both Varget and RL-15 to each other on the different burn rate charts, there is no reason to prefer one over the other.

[mikld]

Every reloading manual I have (13) has a "Relative Burn Rate" chart. But as HiBC noted, it depends on charges/pressures as burn "rate" can change ...

[1MoreFord]

As HiBC said, it's not so easy.

When looking at the posted burn rate chart you can see HP38 and WW231 listed next to each other but they are widely acknowledged as being the same powder in different containers.

The same situation exists with Hodgden HS-6 and WW540 although I don't see 540 on the chart.

I once used, the now discontinued, HS-7 and WW571 interchangeably in .38 Super loads without any problems.

Another of the same situations exist with H110 and WW296.

Burning rate charts are "relative" because of lot to lot variation. You can take two lots of most powders and the two lots will vary enough to garner different locations on a relative burning rate chart.

Have fun.

[gwpercle]

Just about the same....my chart has:
#100 Reloader 15

#102 Varget

Either powder will do fine for both rifles, whichever is on the dealers shelf.
I always hear good things about Varget but can never seem to find any in stock .
Gary

[TJB101]

Found this

{Edit. Please read the board policy on posting copyrighted materials. That chart belongs to Hodgdon. You can link to it, but not post it directly here without first getting their permission. I'll put a link in for you.}

Hodgdon Chart in pdf format.

[Unclenick]

Other burn rate charts:

Accurate

Camden Rod and Gun Club

Castpics

GS Custom

Lapua

Larry Willis

LASC

LHS

Load Data

Norma

Varmint Al

[hounddawg]

It's interesting flipping back and forth and comparing them

[jmr40]

They are both close enough to call it a tie. You'll just have to experiment and see which works best for you and your rifles.

[Metal god]

I’d say Reloader 15 is faster then varget . My thinking is the one that generally creates higher velocities is the slower powder . It may not be universal or even true but that what I do when I’m not quite sure . Also look at several charts and that should give you an idea as to which is which .

EDIT : I should add when I say creates higher velocities I mean when using heavy for cartridge bullets . I'll also add , after more research on the two in your cartridge and bullet weights . The two powders seem about the same in burn rate . I first thought RL-15 was faster but not so much anymore .

[hounddawg]

you got both on hand ? I am a Varget fan for the .223 but RL15 has it share of both. I shoot so I can reload so I would give both a try

[Unclenick]

It's unfortunate that Alliant doesn't list starting load velocities, instead just telling you to knock down their listed load 10% and proceed.

In the 1995 Precision Shooting Reloading Guide, Dave Milosovich developed fixed velocity .308 loads using IMR 4895 and 4064 under 180 grain bullets. Below 2400 fps it took more 4895 by weight than it did 4064, indicated 4895 was slower (more grains needed for each ft/s of MV). But at 2400 fps the charge weight was essentially identical, indicating the burn rates were the same. Above 2400 it took more 4064 than 4895, indicating it had now become the slower burning powder of the two.

So, burn rate is affected by pressure and temperature. Burn rate charts can tell you how two powders compare under the standard burn rate test conditions. The do not tell you how they compare under other conditions.

In the case of the Milosovich test, the number of grains of powder needed to achieve different velocities were straight lines for both powders, but lines that crossed at 2400 fps. If you have the velocities produced by both the starting and maximum loads that are published for a powder and a particular case and bullet, then you can figure our which is burning more slowly at those conditions. Just divide the difference in starting and maximum velocity by the difference in starting and maximum charge. This gives you ft/s/grain (aka, fps/grain) whichever powder has the lower number is having its burn rate less affected by pressure and temperature and is behaving at the slower powder. Just be aware the roles might reverse in a different chambering or with a different bullet weight.

Incidentally, the powder with the smaller calculation result, above, will also be the least affected by other factors that change temperature and pressure and thus is likely to have a wider sweet spot range when you find a tuned load for it.

[Metal god]

I thought the charge weight would be a factor but did not know for sure so I left that out , thanks for the reply UN .

[mikld]

One thing came to mind several years ago when looking for 44 Magnum powders. The charts are all "relative". A listed powder (say #32) may be "faster" than another (#33), but how much? Charts only show if one powder is faster or slower than another, but don't say if the difference is small or quite large. The only thing I found I could be sure of (mebbe) is that there isn't a powder with a burn rate between #32 and #33 powders (just random numbers)...

[Unclenick]

That's why I find burn rate charts like the Europeans use to be more sensible. They group them by which ones are used in the same cartridges. Take a look at the Lapua chart and you see several powders clustered close to each other, as they all apply to the same general range of cartridges, but then have longer lines between the clusters that are further apart. It's more sensible than trying the guess from simple ordered numbers.

And, again, "relative" burning rate means relative to one another under one set of standard conditions, only. The order can change under other conditions.

[Nick_C_S]

That's why I find burn rate charts like the Europeans use to be more sensible.

Yes. "More sensible." Good way to put it.

Conventional charts that simply list an order are inherently deceptive; due to the implied linearity.

And in the case of the Hodgdon chart - which many seem to reference - that thing leaves me scratching my head in a few places. Such as Red Dot being faster (by six places!!) than Bullseye; and Power Pistol being faster (by seven places!) than AA#5. I dismissed the Hodgdon chart years ago.

[RC20]

Or, to US charts, take them as groups.

Anything close is subject to the variation.

A really fast powder though will be fast compared to the mid listed powders.

Manuals like Sierra and Hornady are really nice as they list lots of powders. While not a given with all the powders we have now, if its not listed its cause for pause and careful use even if in the burn area.

[hounddawg]

you have to be careful even with the listed data and always err on the safe side if you are going to err. Use common sense and start low then stop as soon as pressure signs begin to appear