I've done quite a bit of back and forth with Taco regarding the 458 Socom and 338 Spectre over the last few years.
For the NOE HTC459-500-SP (PC and sized .4595") @ 2.18" with CCI 350s
Accurate 1680 - 23.0gr (10.5" barrel - 937 - 1003fps)
IMR 4198 - 22.0gr (10.5" barrel: 968 - 1009fps)
Accurate #9 - 15.5gr (10.5" barrel: 947 - 972 fps / 12.5" barrel - 977-999 fps / 16" barrel - 1045 fps)
I posted extreme velocity swings on purpose, things fluctuate between 40 in the winter and 110 in the summer in the Southeast. It can be surprising to see for the first time going off someone else's data so I like to include it.
I had a 10.5" Tromix for a few years, sold it and got a 12.5" made by Paladin and haven't tried the old loads in the new barrel. All of these cycled unsuppressed yet both of these were pistol length gas systems and my 16" is a bolt gun. Your mileage may vary with the 16" carbine gas system. Granted I was able to have my adjustable block closed beyond 75% restricted and they still cycled, BHO started getting hit or miss around that setting.
#9 has become my favorite for subs, it burns cleaner and is audibly quieter for me when suppressed. I started trying it when I had issues with the NOE 600gr bullet leaving lead on the case mouth with IMR 4198 and Acc 1680 and it also took care of that issue.. Still don't have a definitive answer for that..