7x57R over 12 set arrived today from Tradeex. Fit is perfect. Will give it a try when it warms up and do a video. Have some 173 grain S&B ammo that in rimless form shoots into sub 1 inch in my 21H. Curious to see how the rimmed version will do.
Take a wooden dowel that just fits inside the bore or a stout cleaning rod out with you and shoot the rimless ammo. Just tap the cases out from the front. I've had some combo guns that had an auxiliary extractor machined into the rimmed round extractor to shoot both rimmed and rimless ammo. It's not uncommon to find the set up in 7X57R and 8X57JRS chambered guns.
The extractors are a spring-loaded plunger in the extractor edge that has a radiused side to let it close over the rim and a flat side that engages the rim of the "rimless" round for exaction.
