Last month during a conversation with Ron Smith, Smith Enterprise, Inc., he told me that he was going to have a TRW M14 bolt and the rear half of a demilled H&R M14 receiver tested for surface and core hardness and case depth. Of course, I was very intrigued to hear about this. I mentioned that it would also be interesting if a Chinese M14 barrel could be tested. Without hesitating, he said he would have one tested along with the aformentioned parts.
True to his word, I received a copy of the metals testing lab report on the Chinese M14 barrel this week. The big surprise is that the barrel is made from equivalent AISI 1050 carbon steel. Elemental composition of the steel was as follows: 0.51 % carbon, 0.008 % sulfur, 0.014 % phosphorous, 0.029 % silicon, 0.05 % copper, 0.03 % aluminum, 0.02 % nickel, 0.02 % chromium, 0.75 % manganese and the remainder was iron.
The finish was verified as zinc phosphate coating and the chromium plating thickness measured 0.001 ", as one would expect. The average chromium plating hardness measured 851 on the Vickers 100 scale. The plating hardness meets American standards for hard chroming.
The surface hardness of the Chinese barrel was measured using the Knoop scale. Measurements were also taken at various depths from the outer surface and from the inner surface ranging from 0.002 " to 0.020 " in both directions. The core hardness was also measured. Multiple readings were taken but suffice it to say the hardness was pretty consistent throughout, equivalent to 31 to 35 Rockwell C. This is what you would expect for a gun barrel.
Ron indicated in his e-mail to me with the report that this material is acceptable and that the chromium plating was done well. He mentioned that the British used 1070 steel in the 1880s for gun barrels.
This testing was conducted by a U. S. metals testing lab. The lab included a color photograph of the steel microstructure in the report. The cost of the barrel testing was $650.00. A big thank you goes to Smith Enterprise, Inc. for paying for the Chinese barrel testing and sharing it with us M14 fans. This is another question we can now lay to rest.
True to his word, I received a copy of the metals testing lab report on the Chinese M14 barrel this week. The big surprise is that the barrel is made from equivalent AISI 1050 carbon steel. Elemental composition of the steel was as follows: 0.51 % carbon, 0.008 % sulfur, 0.014 % phosphorous, 0.029 % silicon, 0.05 % copper, 0.03 % aluminum, 0.02 % nickel, 0.02 % chromium, 0.75 % manganese and the remainder was iron.
The finish was verified as zinc phosphate coating and the chromium plating thickness measured 0.001 ", as one would expect. The average chromium plating hardness measured 851 on the Vickers 100 scale. The plating hardness meets American standards for hard chroming.
The surface hardness of the Chinese barrel was measured using the Knoop scale. Measurements were also taken at various depths from the outer surface and from the inner surface ranging from 0.002 " to 0.020 " in both directions. The core hardness was also measured. Multiple readings were taken but suffice it to say the hardness was pretty consistent throughout, equivalent to 31 to 35 Rockwell C. This is what you would expect for a gun barrel.
Ron indicated in his e-mail to me with the report that this material is acceptable and that the chromium plating was done well. He mentioned that the British used 1070 steel in the 1880s for gun barrels.
This testing was conducted by a U. S. metals testing lab. The lab included a color photograph of the steel microstructure in the report. The cost of the barrel testing was $650.00. A big thank you goes to Smith Enterprise, Inc. for paying for the Chinese barrel testing and sharing it with us M14 fans. This is another question we can now lay to rest.
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