Hi Garrick.
I use two piece on my HW100 and have had no problems at all.
The Rifle hold's zero very well.
Some folk's like the one piece mounts, because they say it braces the two parts of the action, but to be honest, I have had no problems at all with the two piece mounts, all down to personal choice buddy.
The Sidewinder is an excellent scope, got the same one on my HW100 and cant fault it, the only problem I feel, is that we are adding even more wieght to what is already a heavy rifle.
Nearly all my shooting with the HW100 is off the bipod in static position, so it does no