Got some velocity data on the Hornady 123gr SST, and the Tula 124gr FMJ, using the Magnetospeed chrono.
16" barrel, carbine gas system, 75F.
Hornady 123gr SST:
2346
2372
2388
2382
2363
average: 2370
Tula 124gr FMJ:
2409
2424
2464
2481
2442
average: 2444