1.) Range increment, it says under advanced firearms that they resolve against touch AC so long as the target is within the first five increments, if a double barrel shotgun has a range increment of 20ft does that mean so long as the target is within 100ft it resolves against touch AC? If so do i have penalties from the range increment being beyond 20ft?
2.) Double Barrel Shotguns have the shatter quality, so does that mean they to resolve against touch AC within the first five increments? So it's a 100ft Cone? or a 15ft cone as per most
3.) I'm confused about the metal cartridges, how many bullets does each cartridge hold? How many pellets does each one hold? If I buy 60 bullets, and 60 pellets(2 handfuls), and I have 10 metal cartridges how does that divvy up?
4.) The double barrel shotgun has a special feature where you can fire 2 shots one from each barrel at the same time as a standard action with a -4 to the attack roll. Do you still get the rest of your attacks if you have a high enough BAB for additional attacks or have another ability that allows for a 2nd attack like rapid shot, or manyshot?
1.) Range increment, it says under advanced firearms that they resolve against touch AC so long as the target is within the first five increments, if a double barrel shotgun has a range increment of 20ft does that mean so long as the target is within 100ft it resolves against touch AC? If so do i have penalties from the range increment being beyond 20ft?
The usual penalty for ranged increments, a -2 penalty to your attack roll per increment beyond the first, still applies even if you are using a firearm.
2.) Double Barrel Shotguns have the shatter quality, so does that mean they to resolve against touch AC within the first five increments? So it's a 100ft Cone? or a 15ft cone as per most
The shotgun states that when you are using it to fire pellets, it fires them in a 30-foot cone. Each ranged weapon with the scatter quality has its own cone range for its scatter attacks.
3.) I'm confused about the metal cartridges, how many bullets does each cartridge hold? How many pellets does each one hold? If I buy 60 bullets, and 60 pellets(2 handfuls), and I have 10 metal cartridges how does that divvy up?
There is no specification that makes metal cartridges any different than typical alchemical cartridges, other than being usable for advanced firearms. Therefore, it is one bullet or one handful of pellets per cartridge.
4.) The double barrel shotgun has a special feature where you can fire 2 shots one from each barrel at the same time as a standard action with a -4 to the attack roll. Do you still get the rest of your attacks if you have a high enough BAB for additional attacks or have another ability that allows for a 2nd attack like rapid shot, or manyshot?
You cannot perform "as a standard action" attacks at the same time as you are performing a full attack action (which requires a full-round action). You must choose one or the other.
Are metal cartridges reusable because that seems expensive to waste one for one.
Are metal cartridges reusable because that seems expensive to waste one for one.
No. Like alchemical cartridges, they are expended upon use.
Price-wise, they are not significantly more expensive than normal firearm alchemical cartridges. While this is certainly more expensive than using ordinary bullets and black powder (which, as it would appear, advanced firearms cannot use), the cost of using them is meant to be a balancing factor to contrast with the obvious power firearms offer.
Note that if your campaign is using the "Guns Everywhere" category, then both advanced firearms and their ammunition cost only one-tenth the listed price (so 1.5GP for a metal cartridge).
By the time you are paying 7,000 GP to get a double-barreled shotgun, paying another 1500 to have 100 rounds of ammunition (which is more than enough to last you for quite a while) is going to be quite sufficient. If you desire a more permanent solution, have the gun enchanted into a +1 Shadowshooting shotgun at the one-time cost of 8,000 GP. (or 4,000 if manually crafting)