Questions about fast ordinance

[Fangmccloud1]

Questions about the fast ordinance of my gun chemist when using the fast ordinance are you technically shooting it at the same time with the first one like you're imbuing two parts of the bullet or is it like shooting one and then quickly loading up another round and then shoot in another ordinance?

[Azothath]

Alchemist arch Gun Chemist

Alchemical Ordnance (Su): ... When loading a firearm, he can infuse the ammunition as a free action. ... if not fired within a number of rounds equal to the gun chemist’s Intelligence modifier (though no sooner than the end of his next turn), the alchemical ordnance becomes inert and loses its additional effects; he can still fire the firearm as normal. Each day, the gun chemist can infuse a number of pieces of alchemical ordnance equal to his class level + his Intelligence modifier, and he can fire no more than one piece per round.
...

Discovery - Fast Ordnance: A gun chemist with this discovery can fire more than one piece of alchemical ordnance as part of a full attack. A gun chemist must be at least 8th level before selecting this discovery.

The choice to do [N] reloads of infused ammo at the start of the GunChmst's round or per shot is going to depend on your BAB, your ability to reload(gun & feat dependent), how long you think combat will last, and your supply of ammo.
I'm assuming a Gun Chemist prepares per reload subtracting from his limit of [GunChmst + Int] AlchOrd for the day. At 8th with Int:14 that's [10] ammo and the ammo infusion lasts 2 rounds. IMO Fast Ordinance is not going to be efficient until 8th+ level.
Situations can happen where a creature cannot take actions so it is prudent not to over prepare but with spellcasters about it is nice to have an infused ammo in your gun so you don't have to start your round with a reload. There are also situations where you might want to target your own square... depends on your 'bomb' discoveries...

[Azothath]

normally reloading a firearm provokes... that can be an issue.

[Belafon]

Ordinarily a Gun Chemist can only fire one piece of alchemical ordnance per round.

Alchemical Ordnance wrote:

...and he can fire no more than one piece per round.

Fast Ordnance just means that you can use alchemical ordnance on more than one shot per round

Fast Ordnance wrote:

A gun chemist with this discovery can fire more than one piece of alchemical ordnance as part of a full attack...

If, for example, you are using a pistol with paper cartridges and have Rapid Reload then reloading becomes a free action and you can make as many attacks as your BAB allows. But the normal limit is "only one piece of alchemical ordinance per round" so the rest of the shots would just be normal firearm attacks. With Fast Ordnance, you can use Alchemical Ordnance on all your attacks in a round (if you want to).

[Fangmccloud1]

So if I am a 4 armed fat folk with two pistols as well as the two weapon fighting style and improve to weapon fighting style as well plus my fast ordinance I could theoretically use 4 ordinance? Five if I was hasted?

[Belafon]

Fangmccloud1 wrote:

So if I am a 4 armed fat folk with two pistols as well as the two weapon fighting style and improve to weapon fighting style as well plus my fast ordinance I could theoretically use 4 ordinance? Five if I was hasted?

Assuming you've got your reload time down to a free action? Sure.

You have the same problem as a regular TWF, hasted, Fast Bombs alchemist. You can go nova for a few rounds a day (3 or so at level 8) but after that you run out of uses.