I have Jap Lewis Type 92 (Aircraft style) that is a lot of fun to shoot. I replaced all that I could with British parts. Nonetheless, my Lewis runs a little on the fast side. I always use 150gn FMJ ball .311 with 38 grains of IMR 4895. It's a decent load. I set spring tension to 12lbs. Anyway, I would like to get to the 450-500 range? Currently, I'm a 600+.