Feats and gear on a magical archer

[ILM]

I'm pretty happy with my human Ranger 6/Trapsmith 1/ Swiftblade 9/ Abjurant Champion 4 build, with Sword of the Arcane Order, Greater Manyshot, Dead Eye and Practiced Spellcaster (also, PBS and Precise Shot so he can use a Splitting Kaorti resin energy composite longbow). The combination of good archery and all the low-level buffs (plus Swiftblade goodness) sounds promising.

Unfortunately, his damage output is fairly tame. At level 20 he can fire 2 Greater Manyshots for a total of 8 Splitting arrows. Let's assume he cast Hunter's Mercy prior to that, you end up with the equivalent of 19 arrows. They'll do, what, around 2d6+25 damage each (strength, collision, knowledge devotion, greater magic weapon, other odds and ends?), give or take? That's a little upwards of 600 damage in the round, but DR hoses him.

Are there any feats, items or spells out there that could significantly alter this equation?

[Psyborg]

The (+3?) weapon enhancement Force turns your attacks into force effects. You now ignore all damage reduction. You are now completely shut down by forceward. You probably can't fire at all within an anti-magic field (though you can fire into one from outside just fine, IIRC).

There's another weapon enhancement that alters your shots to penetrate any DR (probably excepting Epic). Only starts working one round after you first hit that DR, and switching between targets with different DR types can be rather confusing. On the other hand, you're not screwed by forceward.

Making your bow out of Serren wood (BoED) gives it the Ghost Touch effect as a non-magical property.

Edit: Oh, and get rid of Energy. Ignoring physical armor on living opponents is SO not worth being useless against anything that isn't a living opponent- constructs, undead, elementals, etc., etc. Plus, you can't do that cutting-a-rope trick shot with an energy bow.

[Cieyrin]

One of the advantages of archery is, unlike meleers, you can customize your ammo for much cheaper and more freely than main weapons. Just buy arrows tipped with special materials, banes and aligned and you should be fine. Alternatively, Raptor Arrows with the feat True Believer (Ehlonna) will get you reusable bane arrows that become the bane of your target, which, if you can get your bow to at least +4 (whether permanently or via Greater Magic Weapon), you'll be piercing DR/Epic since it will be effectively +6.

[ILM]

Edit: Oh, and get rid of Energy. Ignoring physical armor on living opponents is SO not worth being useless against anything that isn't a living opponent- constructs, undead, elementals, etc., etc. Plus, you can't do that cutting-a-rope trick shot with an energy bow.
You misunderstood me. (http://www.wizards.com/default.asp?x=dnd/ask/20061227a)

Although I've nothing to brag about, since I forgot it shot arrows of force in the first place, so that DR isn't an issue.

Thanks for the ideas so far; anything else? Feats? Other damage enhancers?

[Cieyrin]

Improved Rapid Shot and Improved Precise Shot come to mind but I think you've hit pretty much everything else, especially via Energy Bow Power Shots.