Blued (oil blackened) versus Parkerized

[Bruce_in_Oz]

The "dull ring" is probably because the bodies of No1 and No4 rifles are not all one piece.

On the No1, the entire charger bridge is riveted to the body. The No4 has a pair of "risers" forged and finished machined. The "cross-bar" is then fitted with a variety of techniques, .

ANY "discontinuity" in the structure will "dull' the ring. Also bear in mind the very different steels in use: No1 bodies were a straight Carbon steel. No4 bodies seem to have introduced some additional alloying traces; I do not have the data sheet on this. Any offers?. A "dull" M1 / M14 body is usually the result of Bubbas and Bozos using a long bar of steel inserted through the nag-well as a "wrench", instead of the correctly-profiled EXTERNAL type that fits around the front of the body. The Bubba method can crack the small "bolt-support bridge" inside the body.

Mi and M14 bodies are hogged out of 8620, a serious alloy steel. Carbide tooling was "invented" for such stuff.

Anyone who has played seriously with M1 and M14 receivers / bodies will have noted that a fully stripped body will ring like a bell. ANY "dullness" indicates a fault. Time for the magnetic or fluoro-dye test kits.