Firearms are unreliable. They misfire on a natural 1. Without a gunslinger's Quick Clear deed, fixing the firearm takes an hour. Therefore, the firearm has to be the Savage Technologists secondary weapon. His primary weapon is his melee weapon, as usual for barbarians. In Treantmonk's Guide to Rangers in Pathfinder Treantmonk describes the switch-hitter ranger. The switch-hitter starts combat with ranged attacks, but then dives in with melee attacks. That is how the Savage Technologist will operate, except that the Sword and Gun ability enables safe ranged attacks in the middle of melee, too.
The feats the Savage Technologist will want for gunslinging are Gunsmithng, Rapid Reload, and Deadly Aim. Point-Blank Shot, Precise Shot, and Quick Draw could help, too, but three is already a lot of feats for a secondary weapon. Fortunately, humans receive a bonus feat. Nevertheless, first come feats for melee, such as Power Attack, Extra Rage Power, and Combat Reflexes.
Melee is also first in the point buy for attributes. Go for Strength. Dexterity and Constitution are important, but not as important as Strength. For example, Str 18 (with +2 racial bonus), Dex 14, Con 14, Int 10, Wis 10, Cha 10. Redistribute points among the three mental stats as you prefer.
I play a bloodrager with Primalist and Savage Technologist archetypes. Savage Technologist is not a bloodrager archetype, so I had to adapt it. I experimented for balance and learned the role of each archetype class feature. Let's go over the features from Savage Technologist and see what they mean for the build.
Class Skills. The savage technologist loses Handle Animal and Knowledge (nature) and gains Diplomacy, Knowledge (local), and Sense Motive.
These changes make little difference.
Weapon and Armor Proficiency. The savage technologist loses medium armor proficiency and gains firearm proficiency.
Of course, a gun-toting barbarian needs firearm proficiency. The loss of medium armor proficiency makes the savage technologist more vulnerable in melee. Both make Dexterity more important for the Savage Technologist.
Rage. The savage technologist boosts Strength and Dexterity while raging, rather than Strength and Constitution. And does not take an armor penalty.
We already declared Dexterity important for the Savage Technologist, and here he gains a free +4 to Dexterity while raging. That is why we don't need exceptional Dexterity from the point buy. But Constitution loses its boost, so the barbarian could use a solid natural Constitution. Furthermore, rage becomes the barbarians best defense, too, in addition to his best offense, so the extra round of rage from higher Constitution helps keep him alive, too.
Sword and Gun. With a pistol in one hand and a melee weapon in the other, the pistol's attacks don't provoke. This configuration also gives limited Two-Weapon Fighting. This replaces Uncanny Dodge.
This ability also means the Savage Technologist prefers a one-handed firearm, such as a pistol.
When I removed this ability from my experimental bloodrager, she stopped using her pistol. She was proficient with bow, and the disadvantages of firearms in melee combat outweighed their advantages. When I restored this ability, she returned to her pistol. Shooting an opponent in the face against touch AC after discovering their sky-high regular AC is glorious. Reloading provokes attacks of opportunity still, but one AoO is better than two.
The problem with gun-and-sword combat is that two-handed-weapon combat deals more damage. The Savage Technologist ought to slide between the two techniques based on the best advantage. For example, with enemies at a distance, shoot with only the pistol in hand and reload. The enemy closes in, so draw a longsword and attack one-handed. On the following round, sheathe the pistol and attack two-handed with the longsword.
Primal Magnetism. Better diplomacy with tribal cultures.
This makes little difference.
Crack Shot. Raging gives Dexterity-to-damage with all firearms. This replaces Improved Uncanny Dodge.
Combined with the rage bonus to Dexterity, this is better than a gunslinger's Gun Training.
Finally, some rage powers work well with gunslinging. Reckless Abandon gives a +2 to hit and the -2 to AC does not matter at a distance. Lesser Beast Totem gives claws for the Savage Technologist who always wants a free hand for reloading.
Savage Technologist is my favorite Barbarian Archetype. However it's so good because of the changes it makes to Rage and not because of guns.
You can Play ST without ever using a gun and it's prolly more efficient to use a bow at most times but if guns is what you want then you can make it work as a secondary or primary strategy.
There's actually a fairly nice workaround to the misfire problem. Pick up the breaker archetype and once you have a magical firearm just always fire away even after misfire. The worst that can happen is that your gun is out of commision for the rest of the adventure. So always carry a back up gun.
There's 3 diffferent routes to take with the archetype:
Gun as a back up weapon only. All you need is Gunsmithing and a gun that reloads itself like a Dragon Rifle. You fire a bit before closing into melee. Multiple guns and quick draw will ensure that you can keep firing multiple times per round. I'd go for a two handed firearm and ignore the two weapon fightung ability. This build wants high DEX and STR and some CON. You can get Rapid Shot and PBS but don't really want stuff like precise shot. Pairing this with a natural attack build works out well.
The TWF build using a gun and a melee weapon. This is the build that your abilities are hinting at. After running the numbers on this for quite some time, I came to the conclusion that this isn't optimal.
The Gunslinger Archetype. Maybe dip 1 Level of gunslinger and get all the necesarry feats for ranged combat. Sadly barbarian has few rage powers that supplement this role but defenisve rage powers (Superstition), the one that grants quick draw and Reckless Abandon are good picks. This build prioritises DEX over STR. Also since you need an awful lot of feats human is a must. You can make this work either with two repeating one handed guns or a single two handed weapon.
The best mechanic of SavTech is as a dip for other classes. You can build a horrifyingly destructive Combat Reflexes polearm guy off one of these, especially if you're a half-orc who knows his Teamwork feats.