I finally got this rifle figured out and thought others might be interested, seeing as how so many shoot the Whelen now for "Primitive Weapons Season" in various southern states.
The rifle is a stanless CVA Apex with fluted 25" barrel and one-piece alloy Durasight mount. I was impressed with how tight the action mechanism was, as well as the 2lb factory trigger. I was not impressed with the 2-2.5MOA groups I got out of factory 200gr Fusions. Recoil was also a bit more than I liked (I can admit it). I then tried 225gr Accubonds over 59-60gr of RL15 but made the mistake of partially sizing the brass like I do for my bolt guns. This apparently causes problems in some break-open designs as the action does not lock up consistently. Again, groups were 2-3MOA and recoil was stiff. I stuck the gun in the back of the safe and forgot about it for several months
Not long ago, I read about the importance of headspace with rifles like this. I sized my Federal cases down to where my press would cam-over on the stroke. Accubonds were loaded out to 3.5", which is as far as I feel comfortable considering bearing surface in the neck. To address recoil, I moved to RL10x powder, which Nosler shows in their latest manual as having light charge weights and medium speeds. I looked to the middle of the indicated 44-50gr range and chose 47gr. It shoots MOA pretty easily now, which is a very welcome change.
To make a long story short, dropping 13gr of powder and shedding a couple hundred FPS made a substantial difference in recoil. I should be getting around 2,450FPS from my 25" barrel but the gun shoots flatter than that. Zeroing at 200 yds with the fairly sleek Accubond gave me impacts that were 2-2.5" high at 100yds. I'll chronograph it soon. Shot a broadside doe with the load yesterday at 221 yards and it was point-and-shoot. Nice exit hole, moderate recoil, and a very good blood trail. If a person is looking to tone down a Whelen, think about RL10x and the 225gr AB. I will likely use this "primitive weapon" a fair bit during regular rifle season too.
