Finally got around to shimming 2 Accura V2's (Bergarra) today, mine and my hunting associates. Interestingly, it's a long process but in the end, both rifles close properly and trigger properly with no primer blowback whatsoever. We touched off both mine (that hasn't been fired since I bought it about 5 months ago) and my friend's that has been touched off numerous times. I'm sending Barnes saboted 250's, TMZ flavor and my friend is sending Thor's in FMJ, no sabot. We are both using Blackhorn at 100 grains and both rifles are tack drivers at 100 yards. Both rifles shot with holes touching at 100 (after initial sight in and bore swabbing......amazing. 3 ignitions on each to set the optics (both have Nikon Camo BDC reticle) scopes and 7 more. 10 shots through each and absolutely no primer blowback or bolt face blackening. Far as manufacturing tolerances, mine took a 10, a 5 and a 2 thousands shim to set the retainer where the primer cup was rubbed completely around the circumference while my friend's took a 10, twin 5's and a 2 to achieve thge same result. My friend's was showing a bit of bolt face erosion from blowback, a thing of the past now. I would never recommend the shim kit to anyone without a good working knowledge of the mechanics of fit as it pertains to slam ignition. It's a very fine line between proper operation and unintentional ignition. The retainer must be set where the retainer contacts the primer cup evenly without deforming it and possible igniting the primer accidentially and once the retainer is properly set to a particular brand of primer, you cannot switch primers without resetting the the clearances because different brands have different cup heights and it only takes a couple thousands more to initiate a slam fire. I set both retainers at 10 inch pounds for the sake of repeatability and to provide a constant compression on the 'O' ring on the retainer. I'm using CCI 209 standard shot gun primers btw, n ot the fancy (and way more expensive) 209 inline primers. Not needed.