Aeroprecision AR-10

[Rainman]

Recently I had a round jam in my AR-10. When I attempted to clear it, it was absolutely stuck. Essentially I had to strike the buttstock on the ground while pulling the charging handle back to clear it. When the round popped free, a silver ring also dropped out (see attached photos.) I am a relative newbie to this caliber rifle (had mainly been .22LR and .223 ) so I have no idea what this ring is for and how to proceed from here. I am concerned that trying to just load and fire this rifle and an issue occurring. Any ideas? TIA.

[Rainman]

The ring measurements: 0.810" external diameter, 0.620" internal diameter, and 0.140" at it's thickest point. It has a concave shape on one side and convex on the other.

[98Z5V]

That's a 5/8" muzzle device crush washer, right there.   I don't know why it would be inside the receivers, though. 

[Rainman]

Ahhh... that explains it. I took the muzzle brake off because I was afraid I would need to completely disassemble the upper and run a cleaning rod through. Thank you!

[sketch]

On 11/2/2026 at 7:01 PM, Rainman said:

On 11/2/2026 at 7:01 PM, Rainman said:

Ahhh... that explains it. I took the muzzle brake off because I was afraid I would need to completely disassemble the upper and run a cleaning rod through. Thank you!

 

Did you actually fire a round with the crush washer in the receiver? How is that possible 🤔 I would take it to a reputable gunsmith and have them look it over? *ar10* was this a factory built rifle new or new used? 

[shooterrex]

Did it fall out of the receiver OR did it pop off the muzzle while you were mortering the rifle and went flying near where the brass landed? Did you just take the muzzle device off or did you remove the crush washer also?