Hey folks, long time lurker, never poster.

I'm having an issue that happens infrequently, on average every 150 to 200 rounds fired. In mid magazine my rifle cycles a round, but the trigger and safety lock up. The trigger locks just like I've put the rifle on safe, the safety is locked in the fire position and can not be moved to the safe position despite there being a live round in chamber. The BCG is seated correctly, (not out of battery.) The only way to get the rifle to work is to open it and depress the hammer down with my thumb. (It is locked down when opened, but there is a bit of spring in it and I've found just pushing it down a bit seems too free up the works till it happens again.) I've checked for debris in the trigger from possible blown primers or brass shavings. But have not found anything. (I also haven't seen any evidence of blown primers on the spent brass.) The lower in question is a stock SOLGW complete. With their liberty fighting trigger. Ammo used is both PMC Bronze FMJ_BT in 55gr .223 and 56gr 5.56 German (MEN produced) brass.

Any help troubleshooting this is appreciated. I'm leaning towards maybe a bad spring in the trigger pack. But want too run it by the more experienced guys before I tear it apart.