Hello ABaker,
Personally, I never go afield without a bipod on my T/C's, whether Contenders or Encores. They add a little weight, but not that much and I find that the increased stability of a bipod helps a lot when you have the time to get a steady rest. Even if you can't place the bipod on the ground, a log or some other fairly flat surface, I often grasp the left leg of the bipod (I'm right-handed) with my left hand for a more steady two-handed shot while standing. I don't recommend using the two-handed strategy when your forward hand is near a muzzle brake or when shooting heavy-kickers, but for the lighter calibers it works well - let common sense prevail and you'll be fine.
As jhalcott mentioned, point of impact shifts can be a problem if the forend is not properly secured. To ensure that I don't have problems in that area, I only use pillar-bedding or hangar-bar mounting for my laminate forends, and if I'm using the hangar-bar method, I Marine-Tex the forend to get the last ounce of stability from the hangar-bar mount. It's a little extra work, but well worth your time as far as accuracy is concerned. I feel that the reduction in both vertical and horizontal sighting errors that the bipod provides is well worth the effort, as long as your forend is very secure and your barrel makes no contact with the forend whatsoever.
I have one of the most miserably-chambered, *!#&@! Encore factory .223's on the planet, but with a VV extra-length, pillar-bedded laminate forend, along with judicious handloading processes (that include indexing) and a bipod, it shoots less than half-inch groups all day long at a little over 3,000 fps.
Here's a picture of the gun and an average group:
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Am I a believer in bipods? You bet I am!
Safe and good shooting to you!
Javelina