Ini tweak that opens up all the primary weapons for all your soldiers, regardless of class.
Includes rookies in case you want to give them more oomph.

Instructions

unzip and place the defaultclassdata.ini file in steam > steamapps > common > xcom2 > xcom game > config
Overwrite the file when the prompt comes up.

Default file included under optional files in case you need to revert or you forgot to back up your original.

Does not alter any class skills or secondary weapons.

Game updates may revert these changes, so if it happens, you'll need to reinstall.


There's another file posted on the nexus that pretty much does the same thing, but also has secondary weapons, which are tied to the classes.
So to avoid any issues with mixing secondaries and keep things a bit more reasonable, this only alters the primaries.