Chrome lined rifles require little to no "break-in", that said shoot 20 rounds and then clean her, shoot another 40 or so and clean her again and she should be good to go.
I'd use any M193 round for this process (or any good quality 55grn FMJ from Winchester, Rem, Federal etc...)
For your SHTF or "go-to" self defense ammo, I'd test the Black Hills 69grn SMK, (bullet made by Sierra) and the 68grn match HPBT (bullet made by Hornady) and choose the one that groups best in your rifle.
I might also get one box of the 75grn match HPBT (again Hornady bullet) from Black Hills or Hornady themselves to "see" if the 75grn bullet will shoot well in your 1/9 twist carbine.
Good Luck,
Mike
ps - as your rifle appears NOT to have the M4 feed-ramps I would tend to avoid the Power Points mentioned above and other large lead nosed hunting rounds, as they have "lead-noses" which don't feed as reliably in non-feed-ramped uppers, increasing the possibility of "set-back" (a condition in which the bullet hangs on entry to the chamber and can get set-back into the brass, creating an "over-pressure" issue and the ocassional KA-BOOM)
Yes they (lead nosed rounds) will work in non-ramped uppers, (sometimes reliably), but the shooter must be vigilantly aware that this could happen at any time when using such bullets. The FMJ rounds or the self-defense rounds mentioned above are much safer IMO and this is far less likely with them.
ETA - do not forget that there is very good information TACKED to the top of the Ammunition forum which you should read, like this:
www.ammo-oracle.com and the tesing by B&T Ammo Labs in the top thread.....