I just finished developing loads using 223 cases for my Lar 15, I was successful in meeting my goal of developing loads that shoot groups under one inch and reaching 3000 fps safely with a 16 inch barrel. My next project is to get the same results with 5.56 cases, I have on hand about 300 once fired LC headstamp cases and about 50 cases head stamped PSD. I was under the impression that 5.56 cases were heavier than 223 cases, I weighed a few of the LC cases and they weigh about the same as the Winchester 223 cases that I used to develop my 223 loads.
Being the cases weigh almost the same can I use the same starting load that I used with the 223 cases. I am probably going to stick with just two bullets, 50 gr Nosler ballistic tip and 50 gr Barnes Varminator, that was the only bullet weight that gave me 3000 fps safely only when used with H 4895 powder. I have some 748, H 335, H 4895 Benchmark and Vihtavouri N-135 on hand, the N-135 disappointing, I was getting pressure signs early and way below max load. Benchmark gave the best accuracy with my 223 loads. I appreciate any help or advice.
