For the first time since I bought it I took my Stag left handed upper out. It was mounted on a Spike lower that I had been shooting. I have an EO Tech sight I wanted to sight in. Pulled the bolt back and it would not return to battery. What? So much for shooting. Got back inside (about a minute of walking in the mud) and with some difficulty, worked the bolt and it's carrier forward. Examining the Spike lower, I discovered there was no buffer or buffer spring. The Spike came as a dedicated 22 LR and the small blowback bolt is self contained. It never enters the buffer tube so it didn't have a buffer.
One of these days I'll learn.
One of these days I'll learn.