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Discussion Starter · #1 ·
How do you tell if a gas cylinder is USGI. I recently purchased one from a reputable source & there's no makings on it.
HuntingHawk
 

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GI Gas Cylinders

As far as I know, the only commercially produced M14 gas cy;inders were made by Speingfiels, Inc. and the Chinese. Chinese have metric threads. SA gas cylinders are often very hard, some may not be stainless steel, and the shape, machining, etc., is usually not as nice as GI.
 

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also interested

I would also like to know how to correctly identify a USGI cylinder from a Springfield cylinder. If anyone has any pointers please chime in.. :D
 

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I thought the way you can tell is looking at the (3) splines on the inside of the gas cylinder that rides into the (3) grooves on the barrel. If the corners are square it is USGI and if it is round, it is most likely commerical. It's a tough one to tell.
 

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Discussion Starter · #6 ·
Don't understand what you are saying about using a magnet. Steel is iron ore & carbon. Stainless steel just has a rust inhibitor added, cromium I think. So magnet should work on any steel.
 

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there are many types of stainless steel, some are magnetic and some are not.

IIRC: the gas cylinder is 416 stainless, i dont know if this one is magnetic.
 

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Maybe I can shed some light on this. A good grade of Stainless Steel will not draw a magnet. Stainless steel is regular steel with primarly chrome and nickel added. In this raw form it will not draw a magnet due to the addition of these two elements. However, in the machining process, the material might pick up some traces of regular steel and cause it to draw a magnet. In the marine industry, this is known as 304 Stainless. To achieve 316 Stainless that will not draw a magnet, Molybdenum is added. Boat Steering wheels are made of this so not to draw a compass. I know that 410 heat treated stainless is highly magnetic. Take the word apart and you have the words stain LESS. And that is what it means. It will rust or stain, but not as much. As far as 416 goes, I don't have the answer as I am at work and my gas cylinders are home but I would suppose that given the above, a cylinder made of 416 would be magnetic.
 

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Discussion Starter · #9 ·
Took the SA gas cylinder off. Both it & the USGI the splines are square. Both check with a magnet. The USGI is alot heavier & apprears to be stainless vs plain steel on the SA.
My thought is you can remove the piston & look in the gas cylinder & see if its stainless steel.
HH
 
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