Electroless nickel for firearms - DFW

[The Annoyed Man]

Andy, that's beautiful!

And now..... My turn. The parts are so shiny that what looks like schmutz on them in a couple of places in the 2nd and 3rd pictures is actually reflections from other things:









The finished carbine..... actually an 18" DMR rifle with a rifle length gas system:

[The Annoyed Man]

OK....... Now for the difficulties for anyone who wants to try doing this for their BCG.....

We had some assembly issues putting it all back together. My son is a gunsmith, and he builds AR15s all day long. He knows as much about it as anyone I know, and we still had some difficulty. Everything did go back together, but the tolerances with the plating on were noticeably tighter.

1. The retaining pin for the ejector was a really tight fit going back in. We jury rigged a jig to hold everything together while driving the pin back in, and it made an already difficult job a little bit easier, but it was still very hard. I have ordered the tool for this task from Brownells, and I'm putting off assembling the AR10 bolt until I get the tool. http://www.brownells.com/gunsmith-tools ... 49563.aspx
2. The fit between the OD of the bolt body and the ID of the bolt carrier was extremely tight. It could be jiggered into place by hand, but it was much tighter than normal. We lubed it with some Mobil 1 and tried it again, and it went back in. We worked the bolt back and forth, in and out of the carrier a whole bunch of times to kind of break it in. Now it works, but it is still tighter than a used milspec unit.
3. As part of my rebuild of the rifle, I chose a WMD Nitromet gas tube from Brownells (Brownells.com). This tube is stainless steel, and salt bath nitrocarburized for extra resistance to heat and corrosion. The coating has the appearance of a Melonite or Tenifer coating, and it does add some small amount to the outside diameter of the gas tube. We tested this using the un-plated BCG out of my son's carbine, and it dropped right into place, with no problem from the gas tube. The shop that he works for frequently uses these gas tubes to build custom guns. The difficulty came with the fact that the Nickel Phosphate coating on the bolt parts added a layer to the inside diameter of the gas key. The fit between the gas tube and gas key was tight enough that the plated BCG would not drop into place in the receiver because it hung up on the interference between the mouth of the gas key and the tip of the gas tube.
   
   The solution required that we remove the gas tube from the gun and took a fine grit sandpaper to the first half inch of the rear end of the tube. We removed all of the finish from that end, and probably a very tiny bit of the steel itself. That yielded a fit that would allow the gas key to drop freely onto the end of the tube when the BCG was dropped into the receiver, but it was still sort of a tight fit, and it gives the impression of a bank vault sort of tightness in everything.
4. The fit of the exterior of the carrier to the inside of the receiver itself appears to be normal. The charging handle can easily be retracted, and the bolt flies forward into battery when it is released from lockback. I think that everything will loosen up a little bit when I run some ammo through it. Note that, all by their onesies, the parts feel slick to the touch. YOU STILL NEED TO LUBE THESE PARTS, but you will require less of it, and it will probably last longer. Also, because of the slick, glassy finish, shmutz won't stick to the parts and should just wipe right off.

I don't know what the actual thickness of the plating is that was applied. Andy's parts and mine were all done in the same bath at the same time. It may be that this tightness is normal when plating is applied. I want to emphasize that it was NOT alarming, but it was noteworthy. If you get your parts custom plated, be aware of this. If you buy your parts already plated, the manufacturers have likely accounted for the thickness of the plating......which may be why some nickel boron coatings eventually flake off or wear out.

[J Wilson]

but I like the classic two-tone; it's like my old IPSC Standard gun. Back in those days it was a popular, practical combination - corrosion-resistance on the frame to protect against sweat while leaving the slide blued to minimize glare off the top-end. Companies like Kimber do it the other way around and get it all wrong, IMO.
Andy,I like mine both ways

[ELB]

AndyC, that 1911 does look really really nice now. I may have to consider this for my Hi Power.

Geez, thanks for bring up yet another way to spend my $$.

[ELB]

... and he said he's found that when it comes to male/female parts which have to mate, it's much faster to get a part to fit if the ID is sandpapered as opposed to the OD.

I suppose you could do this (sandpapering ID), at least a bit, before plating, so as to not to thin that plating you just paid $$ to have put on?

[The Annoyed Man]

... and he said he's found that when it comes to male/female parts which have to mate, it's much faster to get a part to fit if the ID is sandpapered as opposed to the OD.

I suppose you could do this (sandpapering ID), at least a bit, before plating, so as to not to thin that plating you just paid $$ to have put on?

In this case, the plating was free, so that wasn't so much of a concern.

I had deliberately decided not to plate either the ejector plunger or its retaining roll pin, exactly because I was concerned that plating all the parts would make reassembly much more difficult, or possibly cause interference in the action of the plunger in and out of its hole. All of those small parts—the ejector plunger, the extractor, the gas rings, and all the assorted retaining pins and springs associated with them—are considered to be "wear out and throw away" parts that should be replaced periodically anyway; so those two things, the disposable nature of the parts, and the possibility of fitment problems are why I didn't plate those parts. As it turned out, fitting the pin for the ejector was a real pain. The pin for the extractor went into place just fine. Apparently, the tolerances there are looser.

We realized that there was a fitment problem between the plated gas key and the WMD Nitromet gas tube when the plated BCG would not drop into position with the upper receiver held vertically. It should have just dropped right in without hanging up anywhere. When we diagnosed it as being a gas key/gas tube problem, we did some experimenting before deciding on our course of action.

1. With the WMD Nitromet gas tube still in the receiver, we took an unplated BCG out of a 16" carbine and dropped it vertically into the upper receiver. It went in just fine.
2. We removed the WMD Nitromet gas tube from the rifle and tried manually fitting it to the same unplated gas key in step 1. It went in just fine.
3. We dropped the plated receiver into the other carbine's upper receiver with its standard uncoated gas tube. It went in, but not quite as easily as in step 1.
4. We tried manually fitting a regular uncoated carbine-length gas tube into the plated gas key. It was a better fit than the Nitromet tube had fit into the plated key.
5. We used a piece of fine grit sandpaper to remove the black nitride finish from the proximal 1/2" or so of the Nitromet gas tube and tried to manually fit the the tube into the plated key. It fit much better than before, but not yet perfect. We continued working the end of the tube with the sandpaper, polishing the end of the tube, and possibly removing a tiny amount of the stainless steel. Then the tube would go right into the gas key just like it should.
6. We reassembled the rifle, with the Nitromet tube, and dropped the plated BCG into the vertical receiver. It dropped in just fine. I took the BCG out, applied a thin layer of Mobil 1 in the critical areas, and put it all back together and buttoned it up. The bolt cycles exactly as it should.

Note, that I chose to modify the disposable part rather than to remove any of the plating.