I am cleaning a bunch of guns for a friend's widow, and fixing problems with them as I come across them, but this one has me stumped. He has a No. 4 that he bought years ago and never fired it. He told me at the time that it had a headspace problem. It had a No. 1 bolt head on it and when I tried it, it worked just fine as long as no cartridge is in the chamber. It closes just fine. However, if you put brass or a cartridge in the chamber the bolt only goes about halfway down until it will not move any further. He had ordered a No. 0 bolt head and it was on his loading bench, so I put it on thinking that might resolve the issue, but the same thing happens. Do you guys have any idea on what may be wrong with it. I know that it appears to be out of headspace, but what specifically might be the problem. I would like to get this fixed for my buddies widow as she said she really wanted all of his guns to work properly.