new member first time posting please dont flog me. At the range first round it happened. Have been reloading round 25 years got the basics down.never had this problem before. Rifle used Belgium fnfal had the gas all the way open so i can single shoot and save my brass. Cases used LC 19 got them new with crimped primers this would be the 2nd loading primers cci no.34 with 43.5 grs varget lab radar sait it went 2550. Used rcbs precision mic to check my sizing. Two things that stick i had to trim cases becouse they grew to 2.025 in length and gas open all way both pieces landed on the bench any thoughts.