I recently acquired some new Rem. .357 Maximum cases and loaded for use in a like new Ruger Blackhawk. Two or three out of every five fired cases split full length. I kept dropping the load and couldn't find a load that wouldn't split the cases. The load was 296 with Rem. 180gr. jacketed bullets with WSP primers. I used loads out of manuels. Any ideas would be appreciated. Thanks and Regards Rich.

My money would be on the brass being too hard, probably from having missed an anneal during production. What I would do about it would depend on how much brass I had. If I had a case, I'd scream at Remington. If I only had a few hundred, I'd anneal them myself. (Put them base down in a skillet with a half inch of water and take a propane torch to the part sticking out for you unfamiliar with the process. In dim light you can see the color change take place at the right temp.)

Far less likely is grossly oversized chambers, but you might as well make chamber casts to check for sure.

Your using the wrong primer #1.You have to use only small rifle primers!!!!!!Small pistol primers are not ment for 357 max loads.I have loaded thousands of rounds with both w296 and h110 no problem.I switched to aa1680 because it burns better in the 357 max.You also have to watch the bullets you use in 357 max revolvers.There are some bullets that will shed their cores.I like .357 hornady xtp bullets only in my 357 max.I use the 180 gr hornady xpt.You have to seat it to the lowest canilure on the bullet in revolvers.I have some good loads never had a case split in around 9000 loads!