How much more H4831SC vs H4831?

[LRSNM]

I'm working up loads for a 7SAUM in a Proof, 18", .195 for 180's and 175's. I have a good supply of H4831 but I'm looking to get just a little more performance. I've reviewed H webpage and the forms but can't find any data that answers my question.
By using H4831SC how much more can I put in a case, .5, 1, 2 grains? Loads are at the point of being compressed, have no pressure signs yet and getting on average 40-50 more fps per 1 grain. I just ordered a drop tube to help also.

 

[just_jon]

I ran QL for 175 ELDX and 180 ELDM. The only difference is fill rate (105.3% vs 101.5% for the 175 and 106.6% vs 102.4% for the 180). Max safe load (< 65,000 psi) is 58.2 grains for both bullets (64,721 for the 175 and 64,820 for the 180).

 

[257Tony]

Yep, Hodgdon will tell you to use the same amount. The SC or SSC version of their powders will meter better, and the standard version will give more case fill if you need it.

 

[QuietTexan]

the standard version will give more case fill if you need it.

That's the kicker. You don't use the SC or SSC for better performance, you speed up to the standard version when you need better case fill with a faster powder than you were using.

Yes that might be backwards of the intention, but it's a practical use.

 

[LRSNM]

I appreciate the info, thanks

 

[grouse]

That's the kicker. You don't use the SC or SSC for better performance, you speed up to the standard version when you need better case fill with a faster powder than you were using.

Yes that might be backwards of the intention, but it's a practical use.

Interesting. Can you elaborate a little more on this?

 

[Oldtime Shooter13]

Faster burning powder in a shorter barrel will give you higher velocities. As long as you can keep total chamber pressure in acceptable limits. In your case 7mm Ultra Mag 65,000 psi. I tend to look for accuracy node more than velocity. If you can find a load with both it happens. But, I usually find accuracy at slightly lower velocity than max?

 

[Mike Matteson]

You might look at H4350 powder. It's a faster burn rate, but you have to work up your loads again.

 

[Roninco]

Faster burning powder in a shorter barrel will give you higher velocities. As long as you can keep total chamber pressure in acceptable limits. In your case 7mm Ultra Mag 65,000 psi. I tend to look for accuracy node more than velocity. If you can find a load with both it happens. But, I usually find accuracy at slightly lower velocity than max?

7 SAUM 65,000 psi. 7 RUM 63,817 psi. According to Quick Load.

 

[entoptics]

Though it can be inferred from what @just_jon posted, to explicitly answer your question...4%.

Ran it through QL for a few different cartridges, and H4831 hits the same volume as H4831 SSC at 4% lower charge weight, so if you're sure you're not exceeding safe pressures with H4831, but you've run out of case volume, you can switch to SSC and get up to 4% more powder in there.

 

[Oldtime Shooter13]

7 SAUM 65,000 psi. 7 RUM 63,817 psi. According to Quick Load.

My bad, I meant SAUM not Ultra Mag. Thanks for correcting.