Purchased from P W Nolan on RimfireCentral.com several weeks ago for my CZ 457 and tested on the range four times, I recommend.
The products works as advertised and I like the idea of loading single rounds for benchrest. Using the five round mag occasionally would not feed smoothly resulting in a 'buggered up' lead nose which I would discard. The Single Shot Adapter eliminates this and loading single/individual rounds makes my routine more deliberate and makes me concentrate on my procedure prior to each discharge. I've been shooting Eley Tenex which, as you know, is not cheap and single shot forces me slow down and get the most from each round.
P W sells the Single Shot Adapter for several different rifles and available in several colors, I bought in Red
Click here to learn more and purchase Mr. Nolan's Single Shot Adapters : https://www.rimfirecentral.com/forums/vbclassified.php?do=ad&id=244199