Best Replacement Barrel for Duck Hunting

[HuntingQuestions1121]

So I own a Remington 870 Express Tactical with an 18.5" barrel. Long story short, my friend has been getting me into duck hunting and I actually shot 2/2 with the short and unchoked barrel. That being said, I love the shotgun and would love to keep using it for duck hunting, but would obviously like a more appropriate barrel for hunting.

I was on Cabela's website (http://www.cabelas.com/product/Remingto ... 705659.uts) and there are a handful of different barrels (vent rib, bead sight, standard contour, etc). Can anybody point me in the right direction of what I'm looking for? (Also, I don't know how practical this is, but the shotgun currently has a ghost ring sight on the receiver with a front sight on the barrel. Do they make longer hunting barrels with a front sight? Yeah, I know I won't really be using it, but still.)

Thanks in advance!

[Synchronizor]

First off, your 870 isn't the type with the nonstandard, single-piece 6-round mag tube, is it?

[HuntingQuestions1121]

Yes, it literally the bottom picture, with Magpul's replacement foreend and stock.

[HuntingQuestions1121]

While I'll probably buy a proper hunting shotgun on Black Friday, if I'm hitting ducks with an 18.5" barrel, how horrible would it be if I just used a choke with the shotgun as is?

[Synchronizor]

Barrel length really doesn't affect patterns much. The same tube in an 18.5" & a 28" barrel - with other things like forcing cone geometry & bore diameter being the same - should produce pretty similar results.