All the major barrel makers make fine accuracy barrels. Only a few will make the longer ones that we like for Ultra longrange hunting. I like at least 36" of barrel for the real long stuff. I have Kriegers, Harts, Lilja and Obermeyer on some of our 1000 yard rifles.
I have a K&P (37") on my 338/416 Rigby and it is very accurate. I also have the Lilja 36" on a rifle and it is very accurate. I have in the closet ready for something exotic in a 30 cal. a 44" lilja. The Krieger is a fine barrel and he will make longer lengths as will Obermeyer.
The Hart, Shilen, Douglas and some others limit the length of their barrels to 30".