Gentlemen,

I had access to a bolt action rifle (Roessler Titan 3 from Austria) in 300 Whisper/Blackout and could test it:

I shot factory ammunition from Hornady, the fast 110grs SST (?) and the subsonic load with a 208grs Match bullet.
Precision was nothing to be excited about, ca. 60-80mm for 5 shots at 100 meters.

I also tested a reload with the Sierra 240grs Match bullet and Kemira N110.
Velocities were around 280 m/sec and the precision also from 60 to 90mm for 5 shots at 100 meters.

The Lehigh Defense company offers expanding and fragmenting bullet for the subsonic loads in 300 Blackout and 308 Win.:
- .308 /(.300 AAC) 168 gr / 10,9 g Lehigh Defense Controlled Fracturing Subsonic
- .308 / (.300 AAC) 174 gr / 11,3 g Lehigh Defense Controlled Fracturing Subsonic
- .308 / (.300 AAC) 194 gr / 12,6 g Lehigh Defense Maximum Expansion Subsonic copper bullet
- .308 / (.308 Win) 176 gr / 11,4 g Lehigh Defense Controlled Fracturing Subsonic copper bullet
- .308 / 210 gr / 13,6 g Lehigh Defense Controlled Fracturing Subsonic copper bullet
(cost: around 65 € for 50 pcs.

Due to the lack of precision I did not intend to hunt with the rifle and have therefore no experience with the bullet behaviour.

The case loads quite easily, however for the subsonic loads I recommend to measure every single load as small differences can result in vertical spread.

best regards
Rolf