excaliber, thank you for your interest in the Atlas. While the Atlas was designed for 30 caliber and under rifles, we have had people using the Atlas on their "heavy" rifles, with the upgrades (what some call V8.1) reports of reasonable success have been received. However, we have never recommended the Atlas (V8.1 or any version) for the heavy rifles as it was not designed for that platform. While it'll support the weight, it's the combination of weight and recoil that stresses the components beyond their intended use. This is why we are bringing out the new Atlas 5-H bipod as it is designed for the heavies up to .50 BMG (read no 20mm!!!) and your rifle will be a perfect match for the 5-H. So if I could make a suggestion it would be stand down on buying an Atlas until the 5-H is available later this year.
(and before you naysayers start in, with the "you've been saying that for over a year now" PLEASE understand that the 5-H is my priority AFTER satisfying customers for our current products)