For Trap - my personal preference is the Browning Citori XT with 32" barrels and the adjustable comb. Its about a 10 lb gun ....but heavier and longer guns are preferred on a Trap field where there is less left to right barrel movement vs sporting clays or skeet ( where guns in the 8 1/2lb range and 30" barrels are more common).
Some shooters prefer the single barrel / break open models ....but they're Trap Singles specific / like the Browning BT-99 or the older BT-100. There isn't anything wrong with them / but the Citori XT lets you shoot singles, doubles and Continental Trap where you can load 2 shells. If I were to choose a single barrel - I would go with a 34" barrel ...for better swing characteristics.
I think the Citori XT is just a better overall gun. I have a couple of them - both 32" / one with a GraCoil recoil supression system on it. The new list price on the XT with the adj comb is around $ 3,200 but I think the street price is about $ 2,900.
http://www.browning.com/products/ca...=citori-xt-trap-with-adjustable-comb-firearms
Browning makes a Gold XT - with adj comb / and the GraCoil installed - and some more engraving on receiver ... list is about $ 5,400 and street price is around $ 4,500 I think .... Its cheaper to have your own GraCoil installed ---but the Gold is a nice gun as well.
http://www.browning.com/products/ca...ri-xt-trap-gold-with-adjustable-comb-firearms
There are also a lot of good used XT's on the market ... In the attached photo of my XT's ....the one with the upgraded wood, is a very nice gun that I picked up used a few yrs ago for around $3,000 ...
http://thefiringline.com/forums/attachment.php?attachmentid=61928&d=1280945127
Now, having said all this ....if all you want to do is shoot Trap casually ...almost any gun will be just fine. I'm assuming you want to shoot Trap fairly seiously / want a dedicated "Trap" gun ... but I was at my club last week .....and shot 2 rounds of Trap with a 28ga, Citori Over Under ....just for the heck of it too ... So your choice of guns - depends on how serious you want to take it.
There is also a unigue new semi-auto on the market now - being marketed as a sporting clays or Trap gun ....Beretta UGB ... Its a break open semi-auto / the 2nd shell loads in a holder placed on the side of the receiver. Its an interesting gun ....retailing for around $3,500.
http://www.berettausa.com/products/ugb25-xcel-trap-12-ga-30/
I think its a gun worth considering as well / and since its a break open gun --- you won't be tossing shells out of the gun at your squad mates either.
But those are my preferences... No matter what / shoot as many different guns as you can / most guys will let you put some shells thru their gun if you approach them properly ... and have fun with the selection process.
Welcome back to our pastime ( I'm not much of a Trap shooter ....more Sporing Clays and Skeet these days ...) ...