Techno did the first sub-20 on White, also with the DAI/Arc Peestol:
Lol, are you telling me that noone had sub-20d white before? Seriously?
Thanks. 
As for BW/Arc pistol, I doubt if arc pistol can be as quick as BW esp. in the hands of a sniper infiltrator. As Alquinn pointed out, BW is much quicker vs. atlases and since I was primarily focusing on atlases in the later waves of my solo, I doubt if arc pistol could match the same speed.
The best I was able to get with arc pistol was 14:09.
Ah, right, I didn't think of TC rank 6. Then yeah, BW is gonna be superior against Atlases by far. Interesting that you focused on them, though. Did you figure it would be faster since you pretty much can alway shoot them or what?
Lol, nice scrubbing on wave 11, yeah XD
Is this the fastest no AC solo Gold time?
Probably, yeah.