Looking at making a swedish rolling block into a 38-55.   
multiple questions.  will the action hold smokless?   barrel twist rate?  bullet weight? for the twist rate suggested?    
bill

paper 200yds

I"m a advocate of the fast twist .375 barrels for long range use.  Mine are 12's.  They are that way to shoot at long distances, in heavy winds.   

However, for what you want, I'd use a 16 twist, or maybe a 14 at the fastest.  The fast twist barrels only come into play using long, heavy bullets for long range use, say 400 to 1000 yards and 360 grain plus bullets.

The rolling block is fine with reasonable low pressure (Not necessarily the same as low velocity) loads.  That means stick with slower burning powders, they take more powder but are much lower pressure and safer than light loads of fast burning powder.  Also helps avoid the danger of double charging a case.

For 200 yard use, I'd use a bullet of about 250 grains.  The lighter bullet and slower twist will reduce the recoil and torque twist of the rifle, making it both more pleasant and more accurate to shoot.  If wind starts messing with the bullet too much, you can go up to about 300 grains readily with a 16 twist.  Some people report tipping bullets at 200 with the 310 grain bullets, but still good accuracy.  Others claim they shoot 345 grains with 16 twist at 200.  I think the difference in opinion is caused a lot by differences in local shooting conditions.

The accuracy game requires the least recoil that you can get and still have consistent performance in the wind at the range you intend to shoot.  That's the reason most competitors are using .32-40 instead of .38-55.  If you're only going to use the rifle for 200 yard target, I'd heavily recommend that you use the .32-40.  The rolling block is also quite safe with that round, as long as low pressure loads are used, which most schuetzen loads are.

good luck!

dave