Given that I can't get RL22 right now, I'm going to load some full velocity practice loads using lower cost bullets with 7828 SSC.
The data in the new Barnes manual is nearly identical with 400gr bullets in the 416 Rigby. I know this substitution will work well, although obviously I'll have to work up again.
I'm just wondering if anyone has any info on how nearly interchangeable these two powders are.

Dear Marty:

I have used RL-22 and IMR-7828 alot in a 7x57 Ackley. I have not used IMR-7828 SC or SSC.

I found RL-22 to be a bit faster than the standard cut IMR-7828.

My research indicates, and this was backed up with a discussion on powders by someone, who used the IMR short cut and super short cut powders, that in his experience the manual listings are not interchangeable for the standard cut and the short and super short cut IMR powders.

Therefore, I'd start at least 5-6 grains below the maximum for the IMR-7828 standard length cut powder listing taking into account the faster burning of the SSC powder.

It may be that IMR-7828 SSC resembles the RL-22 burning speed, but I don't know.

Sincerely,

Chris Bemis

IMR 7828ssc is still a powder not fully discovered by many reloaders. It does not perform like H4831 does compared to H4831sc. Those powders seem identical to me. It has been a wonderful replacement for RL22 for me in the .280 Remington. I don't think this applies to standard 7828 and 7828ssc, for there is about a 2 grain difference max charge in my rifle between the two. A 56gr charge of standard 7828 was nearly compressed as to where a 58gr charge of ssc still has room for more. The 56gr load was max and the 58gr load was not. It's certainly worth a try. 243 shooters will find the ssc version performs well with 100grn bullets also.

Thanks. That's interesting, as the powder companies imply that the burn rates are the same for standard or short cut powders.
The New Barnes manual shows identical minimum and maximum loads for 7828 SSC. Identical charge densities, too. The velocities predicted are nearly the same. I'm extrapolating from here, as I intend to load some Hornady interlocks for full velocity practice, as they are much cheaper than the TSX bullets I hunt with.
Now if only I can get my hands on some 5744, I can load some more low vel practice loads with my cast bullets. I'm down to 100.
My local store (Aberdeen, SD) has a bunch of 7828 SSC, but can't get RL22. 5744 or IMR4831, for that matter. These shortages are getting old.