Home Forums Hunting & Shooting AR and Tactical Rifles Need some advice

Couple weeks ago replaced handguard on one of my ARs. took it with me last week and inserted a magazine and racked a round in the chamber. Flipped the safety off and pulled the trigger and nothing happened. I then noticed that the bolt was not fully closed. Pushed the forward assist and could not get it to fully close the bolt. No problem I will just help the forward assist close the bolt. Once the bolt was closed the gun functioned normal. Problem solved, I had cleaned the bolt when I put the new handguard on so I thought I did not get something in time. Always a first. Shot the mag out and went to put another mag in and racked a round in only to find the same thing, the bolt would not fully close. So I helped the forward assist again but as an after thought I decided to look at things alittle closer and removed the the mag and tried to pull the bolt back. Nothing doing. had to help the charging handle but finally got the bolt to free up. So today I have been playing with it and thought I screwed up the bolt when I took it apart but everything looks ok. Took a spare bolt assembly and put it in the upper and function tested it and it worked fine. Put a dummy round in and it does the same thing will not fully close. Without a round in the chamber everything on both bolts works correctly. My question is when I changed the hand guard could I have changed the headspace? I did not remove the barrel or turn it.