What is quieter with 300BLK: 7.62-SD or 762-SDN-6?

[stevejobs]

This would be with a Noveske 10" upper. I already have an older 18T 7.62-SD but I wouldn't mind dedicating that one to my .308 rifle if the 762-SDN-6 was quieter. The Noveske comes with a 51T anyway, but I'm sure they could put an 18T on it for me if I asked.

[300Blk]

I lost track. We had some guns that were quieter with 762-SD, and some with a 762-SDN-6. Probably the 762-SDN-6 would be quieter with the 10 inch.

[JasonAAC]

Ballpark is -
less than 16", 'N-6 by a few dB
16-18", the same
20+, 'SD by a few dB.

YMMV

[stevejobs]

Ok thanks.

[Tom12.7]

Is that comparison the same with both supersonic and subsonic?
Thanks,
Tom

[JasonAAC]

Is that comparison the same with both supersonic and subsonic?
Thanks,
Tom

yes. the edge goes slightly to the 'N-6 in short barrels with a given ammo and to the 'SD in long barrels with a given ammo.
GENERALLY.

I'd say any difference is harder to hear with supersonic ammo because the bullet crack is loud.

It is not a big difference on either end, just a couple dB.