Been looking at getting a 10" 6.5tcu but,not sure.What's good and what's bad about this caliber.If I get one it will be for paper-killing and maybe a deer or two.

I fired fireforming loads with one once. Very light & accurate. I don't think I had a chance to fire any full loads with it. It is capable of deer witth well placed shots as far as I have read. You could always get that & rechamber if you decide you need more horse power. Good luck
Rich Jake

I've had one for several months and thoroughly enjoy it. With the high B.C. of the various 6.5 bullets you have excellent down-range performance without excessive recoil. Mine is throated pretty long which is tipical so 120 grain bullets will probably be the lightest you will want to shoot. It's a breeze to form brass and reload. In a 10" barrel I don't think there would be much to gain by rechambering to something bigger; IMO the 6.6 TCU is about perfect for your stated purposes.

The little 6.5 TCU is the ne plus ultra for 10" tubes. It will reach 2000 fps with 120 grain bullets, and the Ballistic Tip in that weight is by far THE BEST game bullet available for this cartridge/velocity level. For deer out to 150 or even 175 yards, it will work very well. And, the little cartridge tends to digest just about any load with aplomb. My favored powder is H335; Rem 7 1/2s are just the ticket in primers.

I got mine couple of years ago and it really surprized me.Easy to load and very accurate if i do my part.Mine really likes the 120 grain bullets the best.

I have a 14" 6.5 TCU, and I really like it quite a bit.
So far, it seems to like just about any bullet that I put in it. Like all TC barrels in the TCU series, they are throated REALLY long. I can get 140 grain bullets to get to the rifling, but not by much.
I've tried different powders, but it seems to work best with powders in the H4895/H335/AA2460/AA2520 speed range. Just about every load I've tried with any of these powders has shot pretty well with some being outstanding. Right now, my current fave load is 100 grain HPs/26.0 grains AA2460/Federal 205M primers/reformed Remington .222 Mag cases.

I wonder if one might be better off going with a 100 gr bullet to bring the velocity up a couple hundred fps?

Paul-
If you plan on tackling deer-sized game with it, the 120 grain BT wins hands-down over any 100 grain offering. The extra fps in this case is irrelevant, and the trajectory is really not that much different between top-end 100 and 120 grain loads.

The 120 grain BT is simply much more authoritative when it comes to deer-sized game. I've used it quite a bit and can attest to its excellent performance.