howdy, i have this here 870 its an older express magnum that previously has been trouble free. today i took it out for some fun with Remington 2.75 inch 00 buck. and it would feed the first 4 although rather leisurely regardless of how hard i pumped the action. now the 5 and final shell would still be in the shotshell tube. I'm kinda a Mossberg guy so any help would be greatly appreciated.