From Hodgdons website.

200 GR. Retumbo start 98.0 2992 44,900 CUP 105.0C 3209 52,600

220 GR. Retumbo start 101.0 2954 44,700 CUP 107.5 3155 55,000

After looking at the reloading data, I am thinking that possibly I am getting detonation due to a reloading data problem. Do you thin that Hodgdon has some incorrect data on the 200gr bullet? Here is a 190

190 GR Retumbo 105.0 3154 43,600 CUP 111.5C 3374 54,500