In a recent character creation session my friend and I were discussing feats and weapon qualities. I told him I'ld like to have a fighter who had the far shot feat buy a javelin of distance. He told me that the range incriment increase would not stack from both sources. I disagreed, saying that if it didn't stack, wouldn't it say so... like improved critical and keen? If anyone can shed some light on this discussion, please help. I would be most greatful for any thoughts or rules regarding this.
You're in the right on this point, rules-wise. In the end, it's the DM's decision, but the rules are on your side.
The main question here is: does the javelin then have a range increment of 90 ft. or 120 ft.? By the rules for critical multipliers, it would be 90 ft. (30 base + 30 distance + 30 far shot); however, I've seen a few cases (speed issues, mostly), where you could argue for 120 ft (30 base x 2 distance x 2 far shot).
Secondly, why? Even if you're given the chance to throw at this range (which in most adventures is unlikely, and very improbable in a dungeon crawl), you've now thrown your +1 javelin of distance (worth 8,301 gp) and probably hit (for 1d6+1 plus strength and possibly other modifiers; Average damage is likely around 10 or so with a strong build and feats). If I was a canny enemy, I'd run away with the thing stuck in my chest (and since I'm already pretty far away, you're going to have trouble catching me), and when I get a chance, hawk it to get something that can't be lost so easily.
Now, if you also enchanted your javelin with returning, that'd be more reasonable (though also more costly, of course).
Just my 2 crowns.
They would stack, but I have to agree and say that without returning its all a moot point. You can't do enough damage with a javelin to want to throw it that far anyway. IMO its a waste of money.
Everybody else is right about the dangers of hurling an enchanted javelin over long distances. Have someone grab the javelin after its thrown and steal it or sunder it. The PC will never want to throw his javelin that far away again.
Its unclear according to the rules whether range modifiers stack. Both points of view are quite valid, and since you are the ultimate arbiter of the rules its up to you.
As far as increasing range distances go, I'm pretty sure that the rules for multiplying different types of modifiers apply to everything, not just crit-threat ranges, so IMC a javelin of distance wielded by someone with Far-Shot would have a range of 90 feet. For someone who seriously wants to build a character around lots of throwing weapons, you need to invest in the Quick Draw feat, along with one throwing weapon with the Returning quality for every attack you make in the round. Using Quick Draw, you can throw as many weapons per turn as your BAB allows, and then all those Returning weapons pop back into your arsenal at the start of your next turn. With the right combination of feats, a fighter or even a MC fighter/scout using this build could be a very unique and viable warrior.
The range increment of a javelin of distance is 60 ft. Period. A character with Far Shot doubles the range increment of any weapon he/she throws (a rock, a chair, a javelin, a person). Therefore a javelin of distance in that person's hands could be thrown 120 ft. as its first range increment. Far Shot is simply a martial skill the PC has learned much as many extaordinary abilities (Ex) such as Sneak Attack and Wild Empathy are. Certian skills within this general area like a monk's Fast Movement are clearly described as enhancement bonuses and do not stack with other enhancement bonuses such as with boots of speed because the increased movement they grant is also an enhancement bonus.
This is not the case with the javelin of distance.
For just a little more clarification as to why this is consider what goes into the creation of a weapon of distance: clairvoyance/clairaudience; a divination spell. Whereas, Far Shot is simply a physical skill of being able to shoot or throw accurately further than the average person - simply a bit of extra umph! and a sharp eye.
Now if the prerequisite for making a weapon of distance required that the creator have the Far Shot feat - not the spell above - then a valid argument could be made that the weapon and feat wouldn't stack.
For someone who seriously wants to build a character around lots of throwing weapons, you need to invest in the Quick Draw feat, along with one throwing weapon with the Returning quality for every attack you make in the round. Using Quick Draw, you can throw as many weapons per turn as your BAB allows, and then all those Returning weapons pop back into your arsenal at the start of your next turn.
It's not as good as you think, actually. All your returning weapons come back at the very beginning of your next round. You need a free hand to catch it, or else it falls on the ground at your feet. So once you throw more than two (assuming you only have two hands ;) ), you'll never be able to catch as many as you throw the first round. Here's the quote from the SRD, with the important parts bolded (because underlining doesn't seem to be turned on here):
Returning: This special ability can only be placed on a weapon that can be thrown. A returning weapon flies through the air back to the creature that threw it. It returns to the thrower just before the creature’s next turn (and is therefore ready to use again in that turn).
Catching a returning weapon when it comes back is a free action. If the character can’t catch it, or if the character has moved since throwing it, the weapon drops to the ground in the square from which it was thrown.
My suggestion is to have no more than two with the returning ability, and then have a bunch with other stuff that you can quickdraw for the rest of your attacks in any given round.