@Sduibek.. pretty simple actually
bonus ranged damage was always added +2 or +4 (if taken twice) to the end of total damage calculation..
so for an 10mSMG damage would be like 5-12 x10 bullets x crit per bullet +2 (or 4)= total damage
with crafty's sfall it now does +2 to both minimum and maximum weapon damage.
for example base damage of 10mm SMG is 5-12 dmg with 1x bonus ranged damage it now does 7-14 dmg and with 2x bonus ranged damage would be 9-16 dmg...
so by having a minigun (7-11) with 2x bonus ranged damage would yeald 11-15 dmg x40 bullets x critical strike calculated per bullet. that yealds tremendeus amount of damage.. so if you add "ignore damage threshold" perk to that weapon as sugested by someone in the bug wiki, player would be able to 1shot anyone in the brotherhood and maybe 1shot Master or Lieutenant. Heck i often 1shot a deathclaw with 10mm SMG (even 10mm AP ammo) if i'm close enaugh and make a lucky enaugh roll wich happens like 50% of the time ( mostly dependant on range as SMG has big bullet spread).
Just so You'd know 8x 5mm JHP bullets from minigun does te same job as 40 bullets= rips a deathclaw to a bloddy paste, so an assault rifle would do the job better since it consumes less ammo per burst (8bullets) and has now like 12-20 dmg with 2x BRD.
So adding a ignore damage threshold would yeald probably BIS weapon with just 3 perks (2xBRD and sniper) and if somebody decides to assault the brotherhood it would mean no difference if palladins wear power armor or basic combat armor it would be down to 40% DR as the threshold woudn't matter, so it basically sucks adding it to burst weapons. ignore damage threshold should be a perk given to AP ammo as far as i can see or maybe the 14mm pistol as it only uses ap ammo, but as for the rest a knockback/knockdown or accuary bonus (especially) for the SMG. Minigun also could be more accurate. it does not need to have ignore damage threshold perk.
Also in vanilla shotgun weapons were quite powerfull because of the ammo modifiers.. and now even combat shotgun is just crap. same in Fo2 vanilla game shotguns=bis pre-gauss for small guns and now they just suck. so eigther damage modifier needs to bee brought back OR the need to introduce different shotgun ammo to the game (anyone remember Fo:Tactics : Slugs: thick 'cough' grain;etc) since You do plan on adding restock to merchant's scripts it might be a good idea to start from there
(yeah come to think of it vault13 security team does not need buckshot ammo in their lockers rather those fancy less than lethal riot controll: rubber bullets or "waxshot" grain. On the other hand gunrunners, jake from the hub and brotherhood should have like tungsten-slug-sabot bullets or steel needles buckshot kind of gauge12..
oh yeah as a side note: the ability to trade with brotherhood when you come in with a caravan should also be an option.
the basic principle is they trade weaponry, ammo and meds for food and water. Finally a way to get rid of those pesky mutated fruits, iguanas, those water flasks from v13 or nuka colas for a reasonable exchange rate.