I got the CCOP Mauser scope base in...

It sounded like Russia but is made in China. The steel looks good and all parts were there. Thread pitch was correct #6-48, including a torx wrench to fit. I paid $23 to the door. The local guys I checked with looked at me like I had 2-heads when I talked them about a base to fix my issues. I could tell they were pretending to know what I was talking about, I'm getting old.

I think the relieved style would fit just as well on a contoured sporter FN style, it should be standard. But it remed'd my problem. Now I can fit generic rings and have no worries with the scope.

I'm not much of a rifleman but this is my knock around fun BA. I wanted a .257 Roberts Imp., but the barrel sale they were out of sock so I went with 6mm. It was .243 for a while but it didn't feed smooth and accuracy was erratic. Later I found it to be the rough bore, which I lapped to get accuracy, after I had it redone to 6mm Ackley. It shoots a 85-105 gr. to 3500-3300 fps so that's no too far behind the .257's 120 at 3200. It feeds factory 6mm Rem. smooth but the Imp. cases are chunky and rough, but it works. The 6mm Rem., .257 Robers, 7X57 and 8X57 are all the same case, originally the rifle was the latter, CZ BRNO 1944.

There was a small dimensional problem likely no fault to the base. The extreme hole spacing was about 1mm too far apart. I was able to get the threads started on all screws about 3/4 a turn holding the base upward, then I had to tighten all in turn like lug nuts on a wheel slowly pulling the base down flush. It's not going anywhere since there is some mounting tension, it's solid. Otherwise I'd had to file one of the far holes a bit.