What is the best alround rate of twist for the 35 Whelen??

The usual for .35 is 1 in 16.

hglass-

When I had my Whelen put together about twenty years ago, I went with a 14 twist. It will stabilize the old Barnes and Hornady 275 grain slugs just fine. I have heard that some 16 twist guns will not shoot the longer 250 grain bullets with as much accuracy as the 200 grainers.

I believe that Ruger and Remington both use 16 twist barrels and some of them are very accurate with the 250s.

I also think that Winchester used a 12 twist for their 358.

If you were intending to shoot the heavier bullets, my suggestion is to use a 12 or 14 twist. Those 310 grain Woodleighs are L O N G.

Bob