How Many Rounds For Barrel Break-In

[milehipo]

Ok here's the question
I have a(SSK) AR-15 10" Upper on a RRA Lower Receiver. I am shooting this with a AAC Cyclone Silencer. The optics are a Nikon Monarch 4-16 with a Mildot reticle and Burris steel rings. All is tight and has never had to be retightened since build. Silencer is on tight as well.
The powders I have used are AA 1680,AA#9,and Hodgen H110. I am using Sierra 220 HPBT bullets. Loading for Subsonic use.
My loads are AA#9 8.6gr, AA1680 10.30gr, Hodgen H110 9.1gr.
Load developement done outside, off bench at 100 yards, no wind 65 degrees.
My best group was with AA1680 just under 1+1/2.
COAL is just under PMAG fitment(2.240)
I have about 150 rounds since new build.
How many rounds before barrel is broken in?
Should I be happy with this group?
Should I try a lighter bullet(175)?
Should I increase the load increaments?
SHOULD I START DRINKING!!!