I always use a " full " magnum primer when using IMR 4227 , in 357 , 41 mag , 44 mag and 45 LC . I don't use the winchester / remington " one primer for all " . Personally I use CCI 350 in the larger calibers , usually Winchester or CCI 550 small pistol Magnum primers in the 357 . I have used 4227 for many a year and will continue to use it . You have an interesting problem , if the regular primers solve it , then by all means use them . Regards, Paul