which choke tube ??
 

I have a Mossberg 835 and I usually shoot six shot for pheasent any suggestions on which caliber of choke tube?

With my 835 when I shot it, I tended to use Modified but I also shot steel shot loads. The best is to pattern with the shot shell you want to use and see what it likes. You didn't say weather you are shooting lead or steel.

I use modified as well. I shoot 6s and my buddy shoots 5s.

I have been using modified, but in the past I have also used full.

i shoot #6 12ga remingtons out of a modified choke. that does well for me from 30-35 yards. if you need to shoot out to 40 yards, use a full choke. there are two things to be careful about using a full choke though. the first is that a bird flushed at your feet might not fall to the ground in one piece, and two is that you have a tighter pattern and chances of missing in the adrenaline rush increase. in my opinion, you cant go wrong with a modified choke.

early season i shoot improved cylinder. mostly because im a little rusty since the previous season. but when the birds are flushing agt your toes you can kill em just fine with ic. in mid and late season, i switch to mod. my brother shoots an old single shot 16 choked full. he SLAYS em. haha. its all personal preference. mod is a good starting point for any pheasant hunter.