busted buffer

The plastic plug came out of the buffer today. Thread failure. IIRC 3 weights & thin shim. Haven't weighed it yet, should be carbine. First one I've seen NOT pinned in. Seems lie it rattles a lot more than I'm used to but don't really pay much attention to the buffer. I get another one, just wondering if this thing is really a kluge (given to me) or bad design. Thoughts?

I've not read about that sort of a failure before . I wondered about keeping a poly part attached to metal parts but after knowing the fit and function didn't give it any more thoughts .

All the ones I've ever seen had pins too. Is this for a pistol tube requiring some special length? Have you tried a standard 3-oz carbine buffer to see if it will fit?

I've never seen one that didn't have some sort of stop at the front.
their job is to just punch everything forward.
even the Winchester and Browning systems which push on a rod attached to the bolt have a stop.

2.928 so carbine buffer. Pastic part not beat up, just stripped threads. The thin disk is soft & rubbery.