Can't help on reliable magazines, but I have a 6BR on a 110 long action I use for benchrest. It is single shot no mag with a sled / ramp glued in. I can tell you to get the Improved extractor kit from Fred at sharp shooter's supply. Mine drove me nuts dropping cases.

I tried changing the ball modifying extractor and ejector even springs. I asked Fred and he told me about the kit. Ordered installed and haven't had a issue since. Built on a long action for 2 reasons I had one that had been timed and tried with a nice trigger and a Shehane tracker stock. Barrel is by Hart, real nice consistent shooter.

I use it short range bench rest score shooting. This was my starter rifle however my new .30 BR is almost finished. It will be back to 600 yard for the 6 br soon.