I just picked up an FN Mauser made for Mexico. It is in 6-284. I calibrated the twist at 1:11 and the barrel length is 23" (UNKNOWN MANUFACTURER). What is the heaviest bullet that this barrel will shoot accurately? What is a good load to start with? Of course I want the fastest, most accurate and safest load I can possibly get with the least amount of effort on my part...I want a winning lottery ticket, as well
Bullet stability will depend on weight and length of bullet, velocity and altitude. Berger has a twist rate stability calculator. With an 11 twist, you wont be able to use some of the higher BC bullets due to their weight and length.
For load info, google 6x284 load data and you should get a bunch of results. Nosler, Hodgdon, Alliant and some other sites also have online data. RL17 should be a good performer in the 6x284.
I was thinking of the 6.5x284 when I recommended RL17. It might be a little on the fast side for the 6mm version, but with lighter bullets, it might work OK. Slower powders like Retumbo and H1000 might be good candidates.