I have a G2 and one of my barrels is a 23" bull barrel in 375 JDJ.
The 30-30 is no where near as powerful as the 375JDJ and the recoil, even in a rifle will be quite apparent to you. Mine shoots minute of angle groups at 100 yrds, so you would have no problem at 200yrds as long as you know your trajectory. It is by no means as flat as a 7-30 waters, but flat enough, accurate and packs all kinds of power.
If you are looking for a 200yrd deer rifle though, I would say go with a 6.8 SPC, 7-30waters or something of that nature. The .375 JDJ is a little much for just deer, but makes a great all around big game gun.
If you are not recoil shy and want a rifle that can be used for deer, hogs, and even elk and moose, the 375 JDJ is just about perfect.
Good shooting,
Brian