Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Private
Flight Crew Last 90 Days 7; Flight Crew Total 1280; Flight Crew Type 120
Communication Breakdown; Situational Awareness
Conflict NMAC
Flight Crew Took Evasive Action
Human Factors
I was flying visual by myself learning new autopilot and running it thru the ILS 35 approach sequence but visually. Lots of traffic in the area (at least 3-4 planes). I was making radio calls and position reports and other were also; but it was hard to keep track of everyone. Note BJC was not supporting practice [approaches] due to ATC limits and I think more were flying up north than normal.  Right traffic for [Runway] 28 crosses 35 runway.  I was watching a plane doing touch and go patterns on 28.  I went thru the missed procedure (visually) a little earlier than minimum. I was climbing out on 350 heading; but another plane also crossed from my left and I didn't see [it] until late and until I had climbed to its altitude.  I don't know if it was in pattern or traversing the area.   I was climbing and turned steep left. They also turned steep to their left.  My attention was split mostly outside and but some inside to sequence the AP.  I believe I had right of way; but if there is a collision; it won't matter. I had traffic on my iPad and panel.  But with so many close targets it wasn't useful. Had I not started climb early; I would not have reached pattern altitude so quickly. Also; even if not under the hood a safety pilot is a good idea in congested areas.
Pilot of a light twin flying practice approaches reported an NMAC with another aircraft in the vicinity of GXY airport.