The rifle is a CZ 550 505 Gibbs Safari classic, Bullets are 525gr Woodleigh solids and brass is Norma with CCI magnum primers. Load data is scarce for the 505 Gibbs and most of the information that I was getting is from the Internet. I've seen loads starting at 120 grs of H4831 and all the way up to 142 grs with the 525gr. My first three rounds were 120gr loads and fired with no problem. The load that failed to fire was 125grs. I was going to load with IMR 4831 til I read that H4831 was a better choice because of it being slightly slower than IMR4831. I also didn't want to use a filler like I would have had to with Re15 powder. I used a heavy crimp also and loaded the rifle singularly because I am just load testing. A Lee factory crimp die sounds like a good suggestion but where can you purchase one. The only Lee 505 Gibbs crimp die that I have seen sells from Africa.