Bolt not fully closed and would not open

[bmash]

[Klem]

bmash,

Sounds like headspace.

What is the headspace difference between spent/fired cases from the Lilja, and sized/unfired rounds? Do you know how to measure this?

A related check is to separate the gun and pull out the BCG. Barrel pointing to the floor and drop a loaded round into the chamber. Push on it with your thumb to mimic the bolt slamming it home. Then turn it upright with the barrel pointing at the ceiling and see if it falls out by gravity (it should). If it sticks in the chamber it means there is not enough headspace to guarantee reliable cycling in a semi auto.

Your other guns will all have their unique headspacing so not unusual that reloads work in one gun, but not another. Some chambers are tighter than others but all can still be in spec.

[montana]

Always check head space with any AR rifle and when changing bolts..https://pacifictoolandgauge.com/6-mm...ce-gauges.html

Also check the ejector..Remove the bolt and push on the ejector to make sure it will push flush with the bolt face. I have seen bolts that were not machined properly and the ejector will not push flush with the bolt face causing head space issues..

Klem is correct about variances in chambers..The best check is with a function gauge that is machined to the lowest tolerance that meets spec..The negative with function gauges is very few people/ armorers/gun smiths have them..I have mine custom made with long handles so I can easily check chambers mounted to uppers..https://pacifictoolandgauge.com/func...ion-gauge.html

It also could have just been a case that was out of spec..My favorite method to check loaded ammunition is the Sheridan slotted ammunition gauge..There is a viewing slot that allows access to see where the cartridge is out of spec..https://sheridanengineering.com/prod...unition-gauge/

[bmash]

[bmash]