The easiest semi-auto caliber (for me) is the .45 ACP.
I've used some brass over 10 times before they would split or have loose primer pockets.
The only time I had any bulging was with some loads that were a little too warm.
Most loads were used for target or competition in an old Springfield 1911.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)