N04 & 5 303

I got my enfield well & trully accurate with 1" groups out to 100 yds & more with 174gr heads. I need a 150gr head load with similar accuracy, i tried everything !! with scit results !![B)] Have you got a good recipie for me to try ,for 100 /125 & 150 heads ?They just not enough shooting this cal here , for me to get any ideas, so im hoping you guys can help
best Mond[:)]