I have seen Accutac's ARCA head, and it is not what I would use for a large magnum caliber.
Accutac also makes a model called 17S SPEC-4 BIPOD and a taller 17S SPEC-5 BIPOD. I just ordered one to try. These models can be paired with the RRS SC-ARC Bipod Clamp. I use this clamp on a Ckye Pod with my AXMC in 338 LM. It is a solid connection. I will use this clamp with the Accutac when it shows up, and I have no doubt it will be solid.