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How Do You Tell Stainless from Chrome Molly

416 Views 9 Replies 6 Participants Last post by  dbuckbee
I have a box of Frankenbarrels from GM that are all unfinished. There is a nice 77/22 Sporter in HM2 that SQUAWSACH and I are planning to use in a project but I just don't know how to tell stainless from chrome molly, quite simply they all look alike at this point. I really don't want to throw them out in the backyard to see which one rusts. I need to learn something new.

Thanks

sawdust
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Ya got me on that one.. I've ground lots of stainless and non-stainless knife blades, but never figured out how to tell them apart. Grinding produces a different spark pattern with each though. But, just looking at them, I'm stumped. When I buy the steel, it's marked, so I know which is which. Both are magnetic, so using a magnet won't work.
I kind of like your out the back door idea... ;)
Maybe someone who is a metallurgist will post and educate both of us.
Don
 

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Graybird's not-quite-right. Stainless used for barrels has enough ferric alloy that they WILL be magnetic - enough so that you won't be able to tell that way. (Leupold doesn't sell their magnetic boresighter for nothing).

the bluing trick will work. Cold blue reacts fairly quickly to CM and not so much to SS.
 

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Discussion Starter · #6 ·
Cold Blue

I tried the cold blue on a known Stainless barrel and got nothing. When I did the same to the barrel in question I immediately got color. This only took a minute and now we can plan a finish for the barrel and receiver. It's great to learn something new.

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sawdust
 

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Quite right. No poke at Graybird meant, but I'd been down this road and was shocked to find that EVERY one of my stainless barrels held the Leupold boresighter (magnetic) strong and fast. What a shocker - ain't it REAL stainless? :p

On another note, one of my SS barrels is a Clark SS fluted (beautiful barrel with deep flutes - and it shoots). If I don't apply a bit of oil inside those flutes now and then, they start to gather some rust. So... keep an eye on some of those stainless barrels - a bit of neglect might cause them to rust too.
 

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Good info.
416 stainless used for rifle barrels does have some carbon and is heat treatable. I think the entire 400 series is magnetic. The 300 series is, I think what graybird is referring to. 303 is non-magnetic. However, 304 is magnetic. I use both for different applications. 303 is easily machined and 304 is very tough to work.
I use 416 also for knife guards and it is a pleasure to work (easy) and polishes very well.
Don
 
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