Newbie carbon tuning dilemma

[hayneda]

So I'm back to trad archery after a 30-year hiatis.  I'm trying to take all the advice here and elsewhere to heart and get with the program using carbon's until I dial my form back.  I shoot a Bear Montana 40# with 26" draw.  I'm using Trad Only 600 carbons cut to 28".  Dang these things seem stiff.  Paper tuning looks perfect with a 145gr field point.  But my conundrum is these fly consistantly ~6" left.  If I replace the tips with 125gr, their dead down the middle, although I see some fishtailing early in flight.  Paper tuning with 125gr tips looks stiff.  What gives?

[JRY309]

I have found on some longbows that a carbon arrow can have the affect of bouncing off the riser.I bought some used carbons that were about 1" longer then my draw and showing alittle stiff.So I thought I could add more front end weight to weaken the spine.They got worse the more weight I added.They were showing even stiffer,they were bouncing off the riser instead of flexing around it.They showed stiff with a 125 gr. but even worse with 175 gr and 200 gr.I did tune the same spine arrow to the bow but they ended up about 2" longer.Carbon arrows recover so much faster then wood or aluminum.Their length can have a great effect on them with longbows not cut past center like most recurves are.This has been my expeience with carbon arrows on longbows.I prefer now to start with full length and trim and tune from there.And let my tuning determine my carbon arrows final length.Did you start with full length or cut them to length first?