I have been tinkering with my m700 .270 for a year now, trying to get it set up for long range shooting without much luck so I have gone to the bench to load my  own ammo...I am using Winchester brass....federal primers, 58gr of hodgdon 4831 and nosler 140g BT.  ARe these wise choices?

Yes, I would have to say you are on the right track. I have loaded for several 270's, currently the wife and I both use one. I have never tried the 140's personally but friends love them. I have loaded 130's for hunting only. I have loads for both the Partition and the B.Tip Nosler and they both shoot great. I have found the 270 easy to load for. Every 270 I have loaded for would shoot great with IMR-4350, IMR-4831, and also the H4831. I am sure there is other powders that will perform great also, that just happens to be the ones that I have on the bench. I also have great results with the Fed. primers and the Rem. 9 1/2 primer.
Good luck,
Tuco

One of the aces at a range I used to shoot at in NC gave me this load, said it works like magic in any .270 and I have to say that it certainly does for me.

130 gr bullet (I use Nosler ballistic tips), 60 grains of H4831, any benchrest primer, and seat the bullet .005" off the lands.

60 is the max load recommended by Hogdon for 130 gr bullets.  He told me not to back off on it since a little bit less would likely result in expanded primer pockets but for some reason the full load of 60 would not.  I've reloaded brass with this load 4 or 5 times now with no case problems.

I use this load in a Weatherby MK V sporter and it'll shoot a ragged hole at 100 yards if I do my part.

I've used a few other loads and the only one that didn't shoot very well at all was one of the Barnes bullets - my rifle just doesn't like them.  I use Remington brass and either CCI or Federal BR primers.