Well, for starters I go by and advise from what I had and saw from very early 1968 until I bought my last barrels a few years ago, hundreds of barrels, not some manual. And with Encore's from having them from the start for 3-4 years until I got back out of them and sold them all. That's why you seldom see me comment on Encore's with short personal experience with them, nor G2's with none except seeing and handling the prototype in very early 2K before they became available. I never bought any new G2 Contender era barrels, nor any for Encore's for around the last 10 years.
This thread is about a Contender 10" 30-30 Win barrel assumed to be a standard factory bull.
Most Contender 8 groove 30 caliber barrels were all as I said, 1:10, including the 30 Herrett (the 357 Herrett has the 1:14). The older and very rare for many years now 14" 6 grove barrels are the only difference, and they were 1:14 if I remember. I had one many years ago I had rechambered for the 30 Alaskan, as did other IMSHA friends I shot with. I didn't mention them because they would have just confused the OP even more, and few people here have probably even heard of them except the other old TC geezers like me.
As for the Encore's, their 30's were also all 1:10, including the Herrett and 308 as I said, at least the first years... I have no idea after that.
Take it or leave it, matter's not, that's what I remember.