Powder speed

dhc4ever · Posted: Sun Jul 10, 2011 8:53 pm Post subject: Powder speed

How do you know if the powder you are using is too slow?
I'm currently using ADI 2213sc in a 25/06, but Im not quite satisified with the results.
Thoughts, tips, experiences, over to you.

Ominivision1 · Posted: Sun Jul 10, 2011 11:38 pm Post subject: Re: Powder speed

I tried H4831 in my 25-06 and was not satisfied with the accuracy. I went with varget which is a faster burning rate powder.

The first thing to understand is that we have two limits: cartridge case volume and
maximum chamber pressure! Therefore the powder with the ideal burn rate is
the one that intersects the closet to the intersection of the max volume limit and the max pressure limit!
That is achieving chamber pressure limit with the cartridge case filled to capacity Limit
with loading powder; packing and extracting the maximum chemical energy you can with in the
two limits (pressure & case volume)!

If you use a powder that has a burn rate that's faster than ideal, then you'll fall short of filling the case's entire volume without exceeding the chamber's max
pressure! You'll only get maximum chemical energy in a cartridge when you fill
the entire case volume!

Now if you use a powder with a burn rate slower than ideal, you'll easily be able to
fill the cartridge's entire case volume, but you won't be able to extract all the available chemical energy from your powder charge!

In both of the above scenarios, your muzzle velocities will be below what you
could achieve with a powder of the ideal burn rate!

Usually you can identify the ideal powder in the loading manual by looking for
the powder in the column of the highest velocity with the lowest powder charge
weight! Logic says to go with the one of the highest charge in the max velocity
column, but the actual velocities tend to be lower than published velocities, so you'll
need a little extra available internal room within the cartridge to ad a little extra
to the published powder charge!

Vince · Posted: Mon Jul 11, 2011 12:15 am Post subject: Re: Powder speed

Gidday DHC. What OV1 says is totally correct, but you will still need to be able to identify the difference between a fast and slow burning powder. Easiest way to do this that I know of is to look at a list of powders that is arranged from slowest to fastest, or vice versa. The ADI have such a list on their reloading handbook on their website.

Looking at the loading data for the 25.06 it is easy to see the difference between powders, and as OV1 says...AR2208 (Varget) is slightly faster than AR2213SC. You should determine to capacity of the case (I think from memory there is an article about this on the front page of Hunting Nut) then select a powder that will give you about 80% of that capacity. As an example...using a 75gn bullet you would use 49.7gn of AR2208 fro 3600fps whereas using AR2213SC with the same bullet they list 62gn (a compressed load) for only 3660fps.

Do a little research on the net amongst the powder and bullet manufacturers and study their lists of burning rates mate...then look at reloading data...never try to cook up a load using guesswork data...too dangerous.

Cheers, Vince

Ominivision1 · Posted: Mon Jul 11, 2011 4:02 am Post subject: Re: Powder speed

Here is a burn rate chart that has over 260 powders. Burn Rate Chart

Pumpkinslinger · Posted: Mon Jul 11, 2011 4:35 am Post subject: Re: Powder speed

Vince wrote:

... look at reloading data...never try to cook up a load using guesswork data...too dangerous.

I agree 110% (yes, one hundred ten percent!) with Vince. My "method" for a new load is to pick the bullet I want to use, based on use, then look at the load data for that bullet. I pick a powder that gives the highest velocity and, if possible, lowest pressure. Then work up your load with that powder.

Bushmaster · Posted: Mon Jul 11, 2011 6:30 am Post subject: Re: Powder speed

Vince and Pumpkinslinger have it. Though Pumpkinslinger just simplified it.

ByTheWay...H4831 and H4831SC is better used with heavier bullets. 165 grain and up.

English Mike · Posted: Mon Jul 11, 2011 11:00 am Post subject: Re: Powder speed

H4831 and H4831SC are great powders behind a 130gr bullet in .270 Winchester too.

dhc4ever · Posted: Mon Jul 11, 2011 2:21 pm Post subject: Re: Powder speed

OV1,
What weight projectiles are you using the Varget with?

I was toying with the idea when I've finished the new bottle of 2213sc of going up in burning rate to AR 2209, I hadnt considered AR 2208 (varget) but I am now.
Nozler 115gr Btips are the projectiles I'm attempting to devise a consistent accurate load for.

Vince,
The 2213sc does seem to fill the case quite well between the 48 and 52grn limits its sitting into the shoulder area.

Pumpkinslinger,
That makes sense, unfortunately the ADI loading data doesn't list pressures.

Bushy, Englishmike,
120 - 125grn is the limit in the 25/06, which is one of the reasons I'm wondering if AR2213sc is too slow for the weight of projectiles I'm using.

Keep the info comming

Cheers guys

Ominivision1 · Posted: Mon Jul 11, 2011 3:07 pm Post subject: Re: Powder speed

I shoot with my 25/06 with an 85gr Nosler BT using Varget at 42grs with OAL at 3.225". This load for my rifle gives me the best with accuracy. If I do my part I can print them at less than 1" at 100yards.

1895ss · Posted: Mon Jul 11, 2011 8:30 pm Post subject: Re: Powder speed

Try some IMR 7828, works great for me in my 25-06, at max load.