So riddle me this...powder selection


PDA






mattamus1987
January 29, 2013, 02:14 PM
Ive been reloading for a little bit now, far from expert but powder selection has always kind of confused me. Im looking on HODGON's web page http://data.hodgdon.com/cartridge_load.asp for a good load for 30-06 shooting 190gr. Ive been using IMR4350 and no complaints with it.

Their data shows a 190gr BTSP going 2647fps with max load of 54.5gr of IMR4350. Also lists 58,500 psi as the pressure associated with that.


The same table shows 190gr BTSP going 2608fps with 46.5gr of Varget with a 46,700 CUP pressure accosicated with that.

My question, if Varget is a faster burning powder than IMR4350 and not really recommended for 190gr especially in 30-06, whats the deal with the pressure difference. I understand PSI and CUP dont exactly match up but a 14,000 pressure difference!!! And your getting almost same velocity. So whats the deal, why should I not use a faster burning powder like Varget. It seems the better deal to me, less pressure, less powder, almost same speed. Help me understand im just not seeing it.

If you enjoyed reading about "So riddle me this...powder selection" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
brickeyee
January 29, 2013, 02:19 PM
Between one load using PSI and the other CUP, and these being the peak pressures, not the average pressures down the barrel that determine bullet velocity you are swatting at flies.

rcmodel
January 29, 2013, 02:26 PM
You nailed it with PSI & CUP measurement systems.

They are in no way comparable.

Hodgdon data shows:
IMR-4350 MAX = 54.5 - 2,647 - 58,500 PSI.
H-4350 MAX = 56.5 - 2,692 - 49,200 CUP.
Varget MAX = 46.5 - 2,608 - 49,700 CUP.

Your IMR-4350 would be pretty similar if it were measured in CUP too.

rc

ArchAngelCD
January 29, 2013, 02:31 PM
Agreed, those PSI and CUP numbers are surprisingly similar even though they seem so far apart. It's too bad the powder/bullet companies can't standardize their data but that would mean re-shooting many thousands of of loads which would be cost and time prohibitive.

mattamus1987
January 29, 2013, 02:32 PM
Ok fine so lets say the pressures are roughly the same. Than whats the big harm in using Varget (or any slower burning powder) if im getting roughly the same velocities and its not over-pressuring the gun. Why do people say it isnt "optimal" to use a faster burning powder for heaveir bullets.

BGB
January 29, 2013, 02:38 PM
H450 is my favorite powder for most medium-large capacity cases.
I have reloaded for many years.
I bought a used Ruger #1 243 with this powder and proper bullet lenght I got groups of .25" center to center" @ 100 yards.
I also used the H450 on my Savage 110 E 270 cal and it got sub minute groups with 140 grain BTHP Hornady bullets at 100 yards.

rcmodel
January 29, 2013, 02:40 PM
Why do people say it isnt "optimal" to use a faster burning powder for heaveir bullets.
Because it isn't optimal.

If you can get 50-100 FPS more velocity with the same or less pressure by switching powders, that is optimal.

Perhaps the 30-06 isn't the best caliber to argue about though.

It can make a huge difference in over-bore varmint & big game calibers like 22-250 or a belted magnum.

The 30-06 is much more foregiving.

If you want to use Varget with heavy bullets nobody is stopping you.

rc

ArchAngelCD
January 29, 2013, 02:42 PM
Ok fine so lets say the pressures are roughly the same. Than whats the big harm in using Varget (or any slower burning powder) if im getting roughly the same velocities and its not over-pressuring the gun. Why do people say it isnt "optimal" to use a faster burning powder for heaveir bullets.
Nothing wrong with using Varget, who said that? If Varget will deliver the same accuracy as H4350 then there's no reason not to use it. I usually like to be sure the powder I use almost fills the case because I have found over the years those powders/loads will deliver the best accuracy, slower powders usually fill the case more than faster ones. It doesn't always hold true but it does most times.

kelbro
January 29, 2013, 02:43 PM
It's often the pressure CURVE that makes a powder either more or less suitable for a particular load.

Look at the deltas between the min and the max. If the delta is small (compared to other powders) then the powder is probably going to be more 'spikey' and sensitive and not as highly recommended.

mattamus1987
January 29, 2013, 02:58 PM
And im not trying to advocate one load or another, just trying to better understand the forces at work here, if you will.

readyeddy
January 29, 2013, 03:58 PM
That is an interesting observation. The difference in velocities between Varget and IMR4350 for 180 grain bullets is about 100 fps. But 190 and 200 grain bullets is only about 50 fps. Varget may be more versatile than I thought, assuming accuracy is okay with the heavier bullets.

USSR
January 29, 2013, 06:22 PM
If you want to get the most out of 190gr bullets in the .30-06, then RL22 is the powder. I use it and get 2900fps out of my 26" Krieger while remaining inside of the 60k psi limit.

Don

Jasper1573
January 29, 2013, 07:28 PM
Recommend you try more than two powders before deciding which powder and what load with which projectile is the optimum solution. When I first started reloading, I must have tried half a dozen powders or more in my .308 Win. Settled on one, then swapped back to a different powder for a little more velocity out of a shorter barrel. Once you find the right combination of powder and bullet and brass, you will think, "How much more accurate can this weapon really be?" There is always room for improvement, but most of that lies with the operator.

Jim Watson
January 29, 2013, 07:37 PM
People get all torn up over the difference between CUP and psi.
The point is, that the top published load in either unit is MAXIMUM and you should not exceed it unless you are a proficient handloader who knows more than the powder and bullet makers.

If you enjoyed reading about "So riddle me this...powder selection" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!