Where's to send an action & barrel to get nitrided these days? Send it whole or separated?

Joeymac

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I've had a few custom AR barrels nitrided in the past at MMI Trutec and WMD Nitromet and I've been very pleased with both. Each was well under $100, but I remember a handful of places wanting to charge like $250 minimums and stuff for nitriding, too. Well I have a barreled action that I'd like to get nitrided as well.

So where should I send this thing? It seems like these two places I've used in the past aren't accepting personal work orders (or I I'm just having a hell of a time finding it). Where is the place to have things like actions and gun barrels nitrided nowadays? I know many of the shops (that know what they're doing with gun firearm parts) try to stay at the lower end of the nitride temperature spectrum to avoid tempering issues.

Also, I've never had a whole action & barrel done. Do I need to pull the action apart and have the action/lug/barrel nitrided separately... or do I just get it all nitrided while assembled? I've heard of people doing it both ways and even one of my barrels I had done previously was an entire finished 6.5CM AR10 barrel with the pinned extension still in place.
 
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gnochi

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I say this in the strongest of terms as a professional engineer: don’t. Just don’t.

The action’s job, above all things, is to not explode in your face. Depending on *exactly* which alloy the action is, and how it’s heat treated, and which nitriding process is used at which temperatures, it is very easy to end up with a brittle mess.

I’m not saying you might not get lucky, I’m saying you personally can’t do it safely without far more information than Bergara is willing to give you.

Nitriding is not a coating process. You aren’t just putting something hard and slick on top of the steel. It’s a high temperature conversion process, and you’re turning the steel into a shifting crystal lattice and adding a fuckton of induced stress.

If you want a nitrided action, buy a nitrided action.
 

MK20

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H&M Blacknitride will do it. Pull the barrel from the action. Do your own research and take your own counsel regarding whether or not to nitride.
 

Joeymac

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Properly hardened stress relieved 416R should have no issues with a QPQ melonite process, assuming no one messes anything up in their process. Typical tempers for things like firearms actions and barrels is going to be in the 20-30 HRC range (ideally 24-28 HRC on the barrels; leaving some higher & lower regions for mating components). The range is to allow enough dissimilarity between identical materials to avoid galling. Common 416R temper to get down to 25-26 HRC & 130ksi UTS is approx 1050F/4Hrs.

The high-temp portion of a QPQ process is done anywhere from 900-1150F for something like 60-120min, nominally at ~1075F/90min... of course, this all depends on the parts being run and what the customer specs. So yes, there is some overlap with the age treatment of something like 416R meaning there is a potential someone could screw something up. But even at a maximal melonite temperature profile (~1150F) you're not high enough in the temperature region to really drive the stainless below 20 HRC / 110ksi UTS ... and even then, a 90 minute soak ain't even going to get you that far either because your tempering tables need you to run temp about 4 hours.

Not to mention that this is where a finisher that understands the product material and application comes into play - they keep the process tight and in a most favorable time/temperature zone based on the parts they're running and the customer specs. For 416R firearm parts you'd hope your finisher is processing <1000F which wouldn't even net you a temper below 30HRC / 145ksi UTS even if you ran it for 4 hours... let alone 90min.

I'm not to worried. We don't hear about KB'd actions all over the place despite the undoubtedly tens, if not hundreds, of thousands of rounds fired through refinished-nitrided actions every year.
 
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Joeymac

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H&M Blacknitride will do it. Pull the barrel from the action. Do your own research and take your own counsel regarding whether or not to nitride.
Any idea what they might be charging these days?
 
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MK20

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Call them. They are good folks. I think for a whole gun they are right at 250. I believe you could talk them down for a barreled action. If you do multiple guns they will work you a deal.
 

mark5pt56

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Some years ago I sent mine to Short Action Customs. I would call Mark as he will know at what temp the action was tempered to. I forget the temperature of the Nitriding, somewhere around 1100?

Either way, he will know and does outstanding work.
 

THEIS

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  • Properly hardened stress relieved 416R should have no issues with a QPQ melonite process, assuming no one messes anything up in their process. Typical tempers for things like firearms actions and barrels is going to be in the 20-30 HRC range (ideally 24-28 HRC on the barrels; leaving some higher & lower regions for mating components). The range is to allow enough dissimilarity between identical materials to avoid galling. Common 416R temper to get down to 25-26 HRC & 130ksi UTS is approx 1050F/4Hrs.

    The high-temp portion of a QPQ process is done anywhere from 900-1150F for something like 60-120min, nominally at ~1075F/90min... of course, this all depends on the parts being run and what the customer specs. So yes, there is some overlap with the age treatment of something like 416R meaning there is a potential someone could screw something up. But even at a maximal melonite temperature profile (~1150F) you're not high enough in the temperature region to really drive the stainless below 20 HRC / 110ksi UTS ... and even then, a 90 minute soak ain't even going to get you that far either because your tempering tables need you to run temp about 4 hours.

    Not to mention that this is where a finisher that understands the product material and application comes into play - they keep the process tight and in a most favorable time/temperature zone based on the parts they're running and the customer specs. For 416R firearm parts you'd hope your finisher is processing <1000F which wouldn't even net you a temper below 30HRC / 145ksi UTS even if you ran it for 4 hours... let alone 90min.

    I'm not to worried. We don't hear about KB'd actions all over the place despite the undoubtedly tens, if not hundreds, of thousands of rounds fired through refinished-nitrided actions every year.


    Hi,

    Shit, nevermind....I had a detailed reply typed that showed you are making a whole lot of assumptions in regards to temperatures and HRC ranges, etc etc but then noticed your last sentence...

    For clarity sake... H&M processes at 1200deg and using "time" as the variation depending on alloy specifications and its' heat treatment process/cycle. That is why they ask for the alloy and heat treatment specifications. Guess what??? You do not have them, lol.

    Sincerely,
    Theis
     
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