I am having trouble getting the bolt back into a Remington 581. It will go in most of the way, but will stop half an inch short. I have to pull the trigger before the sear drops enough for the bolt to go home. I tried taking the trigger mechanism apart, to clean it, and looked for anything amiss, but didn't see anything obviously wrong. I am not very familiar with this firearm, so can somebody give me some advice, and/or point me to a parts diagram or exploded view of the bolt and trigger assembly? Thanks in advance.