SR20 PLT INADVERTENTLY ENTERS THE DC ADIZ WHILE ATTEMPTING TO AVOID THE P-40 AIRSPACE.

Narrative

I WAS ENRTE FROM MXE VOR TO MRB VOR. I WANTED TO CLR P-40 BY A WIDE MARGIN; BECAUSE I KNOW THAT THE RESTR AIRSPACE AROUND P-40 FLUCTUATES; AND THE LARGEST BOUNDARY IS NOT MARKED ON THE SECTIONAL CHARTS. I DECIDED TO FLY S OF FREDERICK ARPT (FDK). UNFORTUNATELY; I THINK I FLEW A LITTLE TOO FAR S; AND INADVERTENTLY ENTERED THE WASHINGTON DC ADIZ/CLASS B AIRSPACE. I WAS MONITORING 121.5 AND HEARD A VOICE STATING; IN EFFECT; THAT AN AIRPLANE HAD ENTERED RESTR AIRSPACE; WAS APPROX 13 MI N OF LEESBURG; SQUAWKING 1200; AND THE SHORTEST EXIT FROM THE AIRSPACE WAS 1 MI N. I IMMEDIATELY TURNED N UNTIL WELL CLR OF THE ADIZ. I BELIEVE THIS MISTAKE WAS CAUSED BY MY FAILURE TO ENSURE FLT FREE FROM RESTR AIRSPACE. I BELIEVE CONTRIBUTING FACTORS INCLUDE: 1) THE LARGEST BOUNDARY OF P-40 IS NOT DEPICTED ON SECTIONAL CHARTS. IF IT WAS; I WOULD NOT HAVE CHANGED MY ORIGINAL COURSE TO TRAVEL SO FAR S. 2) FAILURE BY MYSELF TO SPEAK DIRECTLY WITH AN FSS BRIEFER ABOUT THE STATUS OF P-40; AND RELY INSTEAD ON MY DUATS BRIEFING. THE VOLUMINOUS AMOUNT OF NOTAM DATA FROM DUATS MAKES IT TIME CONSUMING; AND OFTEN DIFFICULT; TO ENSURE A PLT SUCCESSFULLY RECOGNIZES AND UNDERSTANDS ALL TFR'S AND OTHER RELEVANT 'POP-UP' RESTRS. I SHOULD HAVE FOLLOWED UP MY DUATS BRIEFING WITH A CALL TO THE FSS FOR ACTIVE NOTAM INFO. IN ORDER TO HELP POSITIVELY IDENT AN ACFT IN QUESTION; THE PERSON WHO IDENTED THE AIRSPACE VIOLATION ON 121.5 SHOULD HAVE ALSO INCLUDED THE XPONDER RPTED ALT; AND POSSIBLY OBSERVED DIRECTION OF FLT. AS SOON AS THE PERSON STATED THE EVENT; I HEARD ANOTHER PLT; E OF BAY BRIDGE ARPT; ASK IF HE WAS THE OFFENDER.