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Nickel M1a1 Bolt?

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Anyone know of any for sale?


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Send a standard blue bolt out to Robar Inc and have it coated, about $45 total. Looks right, wears great, much easier to clean off powder fouling.

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The thing that worries me about hard plating a bolt is accelerated wear on the most expensive part- the receiver. Given the longevity of these guns it may be a moot point, but you can still get bolts fairly readily.
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Hardrede, PK,

I understand your point of hard plating a bolt or any internal component and adding metal, decreasing clearance. I assume that a plating of hard chrome would "transfer" wear from the bolt to the receiver as the bolt would now be coated in a harder metal then the receiver.


I just measured my NP3 coated M1A1 bolt and two blued bolts. The coated bolt width was 1.046", the uncoated bolts were 1.045" and 1.044". I've had several 1911 45's coated and had no problems with fit, function or slide wear, no noticable coating wear in over 1,500rds. Powder fouling from the worst surplus ammo just wipes off.


Some of the facts Robarguns.com claims for NP3:

Catalytic plating process for a very even disposition of coating, within .0002" (they don't state an overall surface size with that spec).

Teflon bonded to nickel for self lubrication properties through out the life of the coating. Robar claims that if both mating surfaces are plated, no lubrication is necessary. (not the case with a Thompson as the receiver is not coated, but on pistols both frame and slide are coated)

NP3 hardness of RC48-51 Rockwell C scale, Hard Chrome is 70-74 Rockwell C.

Will not peel or flake, lifetime guarantee against peeling or flaking.


Do you think there would be any long term effect to using a properly lubricated NP3 coated bolt as there might be with a HC plated bolt?


Value any insight or opinion on this.


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Given the details you provided, I can offer the following thoughts:


The bolts I have tested have been in the Rc48 range, so I can’t see that accelerated wear due to increased hardness would be a problem with NP3; there isn’t an increase. The lubricity built into it would tend to reduce wear, though I would still keep my gun “wet”.


Thickness of the coating (if .0015 or less) would not seem a problem either- Thompsons are not built to sewing machine tolerances in the first place.


So, perhaps this is good stuff. I haven’t had any troubles with the un-coated parts however, so will likely stick with the norm.


Thanks for sharing the details.


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