Some online reading.
http://www.bullseyepistol.com/ There is also a link to Bullseye-L forum, on the page.
Read the rule book online-
https://competitions.nra.org/competition-resources/rule-books/
I retired from competition years ago. So not up on latest guns available. The no longer available Springfield Range Officer model 45 acp was a good starter gun years ago.
Handloads, 45 acp Ammo- i still shoot home cast 200 gr lswc with a reduced load of Alliant Bullseye powder. Starline brass. WLP.
Factory ammo should be available as reduced velocity target loads, in the 700+ fps range.
Avoid mixed range brass for handloads, It hurts accuracy
Someone will come a long shortly that is currently competing. More up to date.