After selecting SR4756 for my 10mm PD reloads, I tried it in my 32.
 

I found only 2 reputable sources for loads with 124/125g. bullets, and, as usual, the max loads varied somewhat; Lyman's is 8.7g. for 1293MV, while Hodgdon's is 9.1g. for 1376FPS, both with 4" barrels.

I assembled five 5-round batches--Speer nickeled once-fired cases, 124g. MontanaGold HP, and WSP primer--for initial testing. Resulting velocities were higher than I thought they'd be; from my 4.5" barrel, the average with 8.3g. was 1360FPS (with screens centered @ 10'), while 9.2g. produced 1429FPS. Primers are still radiused at 9+ grains and functioning was perfect, so I'll now try these with my favorite bullet available ro reloaders, the Hornady XTP.

SR4756 won the muzzleflash wars in my 10mm--see http://jeffreybehr.zenfolio.com/p548446203 --so a load with 4756 and the XTP124 may give the Speer GDLE load #54234 some serious competition. More later.

Good news, friends--I have a higher-velocity, lower-flash, more-accurate PD load, and I'm now carrying it.

After evaluating* 5 different charges of 4756 with the XTP124, 8.9 grains proved slightly better than others. This load develops 1407FPS from my 4.5" barrel (sample size 15; screens centered at 10'); the Gold Dot LE #54234 load produced 1354FPS from a sample size of 21 shots.


* with seven-each 5-shot groups over 2 days

The sig load is kinda watered down, go with CUP specs and watch the numbers grow drastically. Im getting 1560fps with buffalo bore 125gr ammo out of a G31, when i reloaded i acheived slightly higher due to the fact that i can adjust all variants of the round.

Sounds like that might be a powder to try with the longer Barnes bullet if XTP's ever get low in supply.