Was doing fine till about round 160. Hammer went click, but gun did not go bang. Went to pull the bolt back, but it would not budge. Trigger free with no engagement to sear.
Mods while gun was apart for cleaning were: new Mark III complete bolt, VQ sear, Clark bushing and pin. Put new Hogue rubber grips and Hogue screws on to give it a new exterior look. This gun has had a total of 5 to 600 rounds thru it since new.
Today after reading some threads on here, I thought it might have had a trigger or sear pin that walked. Took grips off (checked first for any loose grip screws) Both pins in correct location. Removed both pins, and then the MSH. MSH came out without any excessive resistance. Removed bolt, separated lower from receiver/barrel assembly. Checked all parts with an untrained eye,
![Shocked :shock:](./images/smilies/icon_eek.gif)
Will reclean and put all parts back together.
Any ideas what made the gun lock up?