I am new to small game and rabbit hunting, I currently only hunt deer. I have a Remington 870 12ga with a 20" smoothbore barrel with rifled sights. Can I put a #5 or 6 field shot in this gun and shoot rabbit or is this just a bad idea? a new 26 or 28" vent rib barrel with rem chokes is goona run me about 200 bucks and I just dont have the cash for that right now but want to rabbit hunt! So my question is, can I use my 20" barrel??

Thanks for any advice!!!