Hello - I'm having problems with live rounds sticking in a new COLT LE6920 Carbine. Using factory brass ammo / Remington. Cleaned properly w/ CLP
Will usually fire and eject 1st round in the magazine, but the 2nd round will usually not chamber quite all of the way. Is very difficult to remove the stuck round. Takes a great deal of effort with 'mortor slam' method.
There are visible dark lines inside the chamber that I cannot remove with Blast-Out or CLP. (photos attached)
The first 20 rounds through it were Russian steel case ammo. Didn't have any stuck rounds. Switched to a strictly factory/brass diet and started having the problem.
Are these lines normal or might they be causing the problem? Were they possibly caused by the steel cases?