Which powder?
- Thread starter croberts
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1. Call the Sierra Hotline, 1.800.223.8799, and they can email you the Sierra Load Map for .243 Winchester. It has reliably conservative loads for bullets in that weight range. Always start low and work up.
For the 105s, suitable powders would be H4831 SC, H4350, VV N560, Reloader 22, Norma MRP, IMR 4350, VV N550, Ramshot Hunter. These are selections based on max velocity and near 100% load density. The most accurate load could be a different, faster powder.
For the 95s, try H4350, Norma MRP, N560, Reloader 22, IMR 7828 SSC, Reloader 19.
For the 105s, suitable powders would be H4831 SC, H4350, VV N560, Reloader 22, Norma MRP, IMR 4350, VV N550, Ramshot Hunter. These are selections based on max velocity and near 100% load density. The most accurate load could be a different, faster powder.
For the 95s, try H4350, Norma MRP, N560, Reloader 22, IMR 7828 SSC, Reloader 19.
Wow! Some of those powder choices are way off if you want the barrel to last.
First off, the Shilen barrel is very soft and given my experience will not last long regardless of powder choice.
Shilen barrels are great for 6ppc or simular cartridges, but not good for "full sized" cartridges. ,308 case capacity)
Simply the steel is too soft to take the abuse.
You will get very poor barrel life regardless of what powders you shoot.
However, to extend barrel life, and get the most velocity, you need to stick with single based powders. So Alliant powders are out and 500 series powders from VV are out.
Both work well but will kill your barrel life.
You need to use the slowest burning single based powder you can find to get to your velocity goal.
You can get all of the velocity and accuracy by using slow burning single base powders like H1000 or N165 from both the 105 and 95. The accuracy and velocity you get from the 95 with H1000 will amaze you.
FWIT
Joe
First off, the Shilen barrel is very soft and given my experience will not last long regardless of powder choice.
Shilen barrels are great for 6ppc or simular cartridges, but not good for "full sized" cartridges. ,308 case capacity)
Simply the steel is too soft to take the abuse.
You will get very poor barrel life regardless of what powders you shoot.
However, to extend barrel life, and get the most velocity, you need to stick with single based powders. So Alliant powders are out and 500 series powders from VV are out.
Both work well but will kill your barrel life.
You need to use the slowest burning single based powder you can find to get to your velocity goal.
You can get all of the velocity and accuracy by using slow burning single base powders like H1000 or N165 from both the 105 and 95. The accuracy and velocity you get from the 95 with H1000 will amaze you.
FWIT
Joe
Forum Boss
Administrator
Joe,
I won't comment on the Shilen barrel life issue because there are certainly differing views on that subject.
The use of extremely slow burn rate powders is one strategy for the .243 Win case,and similar wildcats), and "overbore" cases such as the 22/250. However, I don't think it's accurate to say that powders such as H1000 and N165 will give the highest velocities.
For a standard .243 Win with a 28" barrel, shooting the 95 Noslers, H1000 and N165 are well down the list in terms of the velocity they can achieve at 60,000 psi,Max) and a 102% case fill,Max). Note the .243 Win is SAAMI rated at 60,000 psi. See: http://www.handloads.com/misc/saami.htm
A 49 grain load of N560,100.3% fill) is rated to 3325 fps velocity with the 95gr Noslers, 60K psi max. IMR 7828 SSC is rated to 3310 fps, 60K psi max. A 49.1 grain load of H1000,102% fill) is rated only to 3102 fps with a 50,061 psi, with a 97.3% propellant burn. [For comparison sake, the Hodgdon Online Load Manual H1000 max load for .243 Win and 95gr Nosler is 48.0gr COMPRESSED at 3077 fps]. A 47.7 grain load of N165,102% fill) is rated 3139 fps at 56,554 psi.
These are QuickLOAD projections and obviously reality may be different, but in general we've found the projections accurate within 30-50 fps,,and closer if we have the actual case capacity).
The "secret" of the slow burning powders in extending barrel life may not be so much in their burn properties as the simple fact that you cannot get enough powder in the case to reach maximum-rated pressures. ANY powder running at 50,000 psi is going to give longer barrel life than the same powder at 60,000 psi.
That's not to say best accuracy may not be achieved at those lower pressures with slower powders. I'm strictly talking velocity here.
But I think it's misleading to suggest you can drive a 95-grainer faster from a .243 Win with H1000 or N165 than with some of the other powders mentioned. If you look at various load manuals,not just QuickLOAD) you'll see you run out of case capacity with H1000 and N165 before you hit the pressure limit with a 95-grainer.
I won't comment on the Shilen barrel life issue because there are certainly differing views on that subject.
The use of extremely slow burn rate powders is one strategy for the .243 Win case,and similar wildcats), and "overbore" cases such as the 22/250. However, I don't think it's accurate to say that powders such as H1000 and N165 will give the highest velocities.
For a standard .243 Win with a 28" barrel, shooting the 95 Noslers, H1000 and N165 are well down the list in terms of the velocity they can achieve at 60,000 psi,Max) and a 102% case fill,Max). Note the .243 Win is SAAMI rated at 60,000 psi. See: http://www.handloads.com/misc/saami.htm
A 49 grain load of N560,100.3% fill) is rated to 3325 fps velocity with the 95gr Noslers, 60K psi max. IMR 7828 SSC is rated to 3310 fps, 60K psi max. A 49.1 grain load of H1000,102% fill) is rated only to 3102 fps with a 50,061 psi, with a 97.3% propellant burn. [For comparison sake, the Hodgdon Online Load Manual H1000 max load for .243 Win and 95gr Nosler is 48.0gr COMPRESSED at 3077 fps]. A 47.7 grain load of N165,102% fill) is rated 3139 fps at 56,554 psi.
These are QuickLOAD projections and obviously reality may be different, but in general we've found the projections accurate within 30-50 fps,,and closer if we have the actual case capacity).
The "secret" of the slow burning powders in extending barrel life may not be so much in their burn properties as the simple fact that you cannot get enough powder in the case to reach maximum-rated pressures. ANY powder running at 50,000 psi is going to give longer barrel life than the same powder at 60,000 psi.
That's not to say best accuracy may not be achieved at those lower pressures with slower powders. I'm strictly talking velocity here.
But I think it's misleading to suggest you can drive a 95-grainer faster from a .243 Win with H1000 or N165 than with some of the other powders mentioned. If you look at various load manuals,not just QuickLOAD) you'll see you run out of case capacity with H1000 and N165 before you hit the pressure limit with a 95-grainer.
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