Had the Same problem with mine a few weeks ago...
I just took a small cleaning rod and reached up through and pulled the part back down,
I guess its the firing block or something like that its the part thats susposed to be down when reasembling mine got bumped when the pin wouldnt go back in easy, I guess it will get better when it loosens up some,
just take the cleaning rod and look up through the magazine area and you can use the tip too pull the block back down and the bolt will come out..
I was pulling my hair out for about 20 minutes before I figured it out,
after that it was pretty simple...Jim