Bartlien MOD 400, experiences?

[jelenko]

No Sir,
Micron is metric = 1 millionth of a Meter
Not Microinches but more like = 1/26,000 of an inch
(I understand, it can be confusing when they throw in metric with our inch units)
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118 millionths of a meter is equal to .00465"
1 Micron is approx. .000039" or .039 of one thousandth
so 3 x .000039" =?

Well, there you go!

Thanks!

 

[Bob3700]

Is this more of a Melonite? rather than Ti Nitride?

Salt bath nitriding. It turns the surface satin black.
The process is also used on small aircraft brake rotors. A surface hardening.

 

[WSnyder]

A surface hardening

Mmmm....more of a case hardening since it (hardness properties) goes deeper than just the surface. Depending on alloy it might be .002-.010" deep give or take. The black aspect of it is as you said is more or less on the surface and it can or will wear off with enough use.

 

[jthor]

I’ve used 3 mod 400 barrels on my 6 dasher and I’m on my 4th. AT 2800 rounds they were still shooting.

 

[Bob3700]

Mmmm....more of a case hardening since it (hardness properties) goes deeper than just the surface. Depending on alloy it might be .002-.010" deep give or take. The black aspect of it is as you said is more or less on the surface and it can or will wear off with enough use.

Uses, the hardening penetrates the metal a few thousands deep. I have not seen the satin black wear off on the outside of the bbls yet. Inside, with a bore scope, they shine. .

 

[WSnyder]

I have not seen the satin black wear off on the outside of the bbls yet.

I have seen the black on bolts and inside actions wear to the point that they aren’t solid black and bare looking metal appears.

 

[jelenko]

I have seen the black on bolts and inside actions wear to the point that they aren’t solid black and bare looking metal appears.

Same here. Somewhere around 1000 bolt cycles. The action was also smoother as the bare spots began to show.