Buff dmg of sawn-off to be in the middle between shotgun and remington and add one, two or three perks Or one trait.
About guns...dunno what have you planned, but it would be nice to see...Famas
M79 Grenade Launcher, Saiga shotgun, 9mm Beretta pistol, maybe different UZI for 9mm, MAC-10 smg, I would add some (at least two different) upgrades for Stoner as it was quiet fancy and original module mg/ar.
From carbines maybe 98k, Gewehr 41/43 and maybe those above uprgraded versions with scopes.
And of course rocket launcher with 4rockects from commando movie and fancy ppsh with low range, big spread and awesome firerate for sending walls of leads to our enemies.
Of course this year I was a good boy dear Santa Claus, papa Cirno and Uncle Johnny P.