Does anyone have any experience with the 348win in the carbine version if the model 71?what kind of velosity can be had with 250gr bullets.Is the 348 enough for moose and bear up to 150yds.

In it's day the .348 was highly reccommended for moose and big bear, it is the equal of the .358 winnie. I have seen listed factory ballistics of 2300 and 2350 ft/sec for 250 grain bullets. It would be good for 150 yards.

I have gotten up to 2300 fps in a Browning 24" rifle version with H-380 and 250 gr Hawk FN's. The load was at the edge for my gun and I currently run at 2250 fps. This load left a large exit wound on a broadside elk, should work good on moose, but I'm not sure if it would go deep enough on a big bear. Some people have good luck with the Barnes 220 gr X bullet, just besure the bullet nose is round and not jagged.
Take a look at http://www.mindspring.com/~ulfhere/ballistics/methods.html#medium_bore
for some comparisons.

I shot a couple of deer with the old 250 gr. silvertips and it hammered them...I have seen elk shot with them and they worked fine in the timber.

they sure are nice guns....

My 24 inch barreled rifle gets about 100 fps more than my 20 inch barreled carbine - about what you'd expect. I have read folks (Boddington for example, who is a Model 71 fan) question whether the claimed velocities of 2350 fps were ever really achieved or if that was just optimism. I think 2150 to 2200 fps is probably the realistic top end for the carbine. As mentioned, I saw excellent performance with the 6-petal 220 gr X-Bullet. Velocity was 2275 fps, but I did not push loads or try different powders. I back off when extraction gets sticky. In my experience that is where a Model 71 finds its limits, rather than action strength per se. Townsend Whelen thought this was an excellent all-around North American big game caliber for woods hunting. Standing, I can shoot better with my aperture sighted model 71 than with my scoped bolt actions. Really fun rifle!