Hi. I need to cast more than 1000 bullets per week. I always used Lee 6 cavity molds, but, after making around 25000 bullets the skrew wich holds the sprue plate become damaged and loosed up. This happens with all the Lee molds and it is not easy for me to fix it. Do you recommend me to change to another brand? Are the iron molds more suitable for this purpose? In this case which mold do you suggest?