Gunsmithing Salt bath nitride coating on a bolt.

[Ksheff]

I’m finishing up a rifle build and I want to coat the rifle bolt and handle black. I considered a microslick cerakote, but I think the SBN finish will be more durable and perform better at the same cost. I also have a local company that does melonite.

My question is how does the coating effect the product dimensionally? if I coat the bolt and handle, will I have trouble reassembling the firing pin, threads for the knob, etc?

 

[alamo5000]

As far as I know it will not impact anything dimensionally.

 

[Austan]

It shouldn't be a noticeable difference with SBN. It should only add about a thou to the surface. I'm going from memory but it can be easily looked up along with the other coatings.

 

[Supersubes]

The only answer here is to call the action manufacturer and see if the part will take nitriding. What the alloy is and where it starts from matters.

You can also DLC the bolt, which is low temp.

 

[Hateca]

You can’t blindly nitride anything. You need to know the makeup of the part and any prior heat treating. As said above call the part maker and see what they say.

 

[Yondering]

My question is how does the coating effect the product dimensionally? if I coat the bolt and handle, will I have trouble reassembling the firing pin, threads for the knob, etc?

It's not a coating, it's a surface treatment; it doesn't build up anything on top of the surface. The only potential dimensional changes are from metal movement (warping, shrinking, etc) from the heat involved in the process.

Hateca's comment is important though.

 

[MK20]

Blacknitride from H&M does this all the time.

 

[Totoro]

+1 for H&M

All my Atlas actions have nitrided bolts from H&M and have no complaints.

 

[hermosabeach]

+1 for H&M

All my Atlas actions have nitrided bolts from H&M and have no complaints.

what do they charge for an action? ballpark price?

 

[Totoro]

From Kelbly's or having H&M refinish?

The Atlas actions a little north of $1k already nitrided and ready.

To have H&M nitride, I havent got the foggiest.