lookin to get a 270...
i am lookin at barrels and am wonderin what everyone thinks of the canted land?
and since im throwin a break on it, do ya think my 12y/o daughter would be able to handle it in a mag? she is comfortable with a 223, but put up quite a fuss with a 20ga with high brass.

Canted lands tend to have a touch faster MV and are easier to clean. I LOVE my Broughton 5c! But, I also wouldn't make it the deciding factor either, stick with name brands and a good smith and you'll be fine.

What kind of break? And what do you mean "mag"? Are you building a .270 Weatherby Mag?

Since JK is answering the tech part,I'll try the physical part... some shotguns can kick like a Missouri mule, and if that's what she got busted with, just hope she doesn't start to become recoil-sensitive. I truly think the .270, whether it be standard, Roy, or WSM may be too much for her.... She's only 12...

yeah, im building one. i havnt picked a break yet.
i been shopping fer barrels and saw the canted in a 10 twist.
got ta thinking about a break, and thought why not make it a magnum, as i am lookin for potential 1" groups at 600 yards. but it is fer a 12y/o..she wears a woman's size 11 shoe...11 and 1/2 in some brands.
she is 5'9" and weighs about 145lbs.
need a built in mag, so a rem 700 action?

The 700 is a fine place to start if you are looking to build an accurate hunting rifle at a reasonable price.
However, if you are looking for record-setting benchrest accuracy you would be best served by starting with a BR action. The hottest action in BR now is the BAT. A BAT action is very stiff, all steel and can be had with a magazine cut. Be prepared to pay about $1,300 for the action alone if you go this route.
You might be able to build a rifle that can shoot an ag of 1 moa or a bit better at 600 if you build on a 700 action. Small groups are possible with quite a few rifles, but rifles and shooters that shoot small ags are rare.

Not sure about 1" groups at 600...1 MOA surely.

The worst thing about the .270 (all of them) is the availability of long range bullets...

700's are a great action to start with.

Even a 6.5x.284 would be an excellent choice...

Whatever brake you decide to go with-remember to use a timed brake-not an untimed one. Otherwise you'll have dust/mud/snow/grass flying up and all over when you shoot from prone.

Been there, done that...doesn't help with the mouth open either!!