Connected:armalite ar 10vintage gun partsshotgun partsrifle parts lotsurefirerifle barrelgun partsrifle stockrifle parts usedrifle parts .223rifle accessoriesvietnam rifleYou got it suitable. It is a screw-on choke tube. It is really at the very least much like the Lyman/Cutts choke tubes that are still out there on eBay and thru other resources ()