Rainier Arms Match Grade NiB BCG

[kravman4]

I just purchased a BCG from Rainier Arms and am curious what you all think about the NiB coating. All the external contact surfaces are nice and smooth, but as you can see in the pictures, there are some irregularities on the inside of the carrier and near the gas ports. There is also some roughness on the bottom edge of the carrier near where the hammer swings through to hit the firing pin (nomenclature?).

I am looking mostly to hear from people in the industry (guns, metallurgy, etc) who can tell me if these are clues to poor NiB that will lead to problems in the future or is this just cosmetic?

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[milotrain]

Not in the industry but nothing you posted looks strange for general fit and finish of BCGs. I don't know what about a BCG could be considered "match grade" nor do I see much benefit to NiB coatings but I don't think you can go far wrong with a BCG that's in spec.

[fritztkatt]

I'd only worry about it if there's massive trouble spots where the gas rings ride or the bolt tail (nomen?) pass, also on the rails where the carrier rides in the upper.

Other than that it's all cosmetic IMO.

Please, if I'm wrong, educate me.

[kravman4]

That's what I'm thinking, just don't want to run into issues with the coating flaking or causing carbon buildup in the future...

[AreWeFree]

Not in the industry but nothing you posted looks strange for general fit and finish of BCGs. I don't know what about a BCG could be considered "match grade" nor do I see much benefit to NiB coatings but I don't think you can go far wrong with a BCG that's in spec.

^Great answer.

[penguin0123]

Those are non contact surfaces, I understand why the mfg wouldn't spend machining time to clean those up.

Rainier has always been a stand up shop, so I think you can rest easy.

[kravman4]

Those are non contact surfaces, I understand why the mfg wouldn't spend machining time to clean those up.

Rainier has always been a stand up shop, so I think you can rest easy.

That makes sense. This is the 2nd NiB bcg I've had so I don't have much hands-on time with this finish.

Rainier Arms is an EXCELLENT company. I signed up for their Apex program as soon as they introduced it.

Only reason I brought this up here was I am planning on running this bcg in a match on Monday and was going to hit the range to get it broken in tomorrow. If the coating was an issue I didn't want to put rounds through it...

[ar15barrels]

Those areas you photographed are non critical areas that nothing comes into contact with during operation.
Therefore, the things you see are purely cosmetic.
The coating looks fine.
Those things you see are actually in the underlying metal that the carrier is machined from.

I just purchased a BCG from Rainier Arms and am curious what you all think about the NiB coating. All the external contact surfaces are nice and smooth, but as you can see in the pictures, there are some irregularities on the inside of the carrier and near the gas ports. There is also some roughness on the bottom edge of the carrier near where the hammer swings through to hit the firing pin (nomenclature?).

I am looking mostly to hear from people in the industry (guns, metallurgy, etc) who can tell me if these are clues to poor NiB that will lead to problems in the future or is this just cosmetic?

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[mif_slim]

Yeah, i only heard of bolt being match grade for the barrel its going to come in contact with, but not one made out of the blue to be match...whats it matched with?

I have a NiB BCG and it works just like my other BCG...just easier to wipe and you can see the carbon much sooner than regular BCG.

[major burnout]

They have sold a ton of standard barrels for big bucks by simply slapping 'match grade' on them. I guess they are selling 'match' BCGs now. Im going to wait for the 'ultra select match' BCG, NiB of course.

[PachecoFTW]

Those are only cosmetic flaws.

Wear points are bottom of carrier that resets hammer and guide rails, as well as where it contacts charging handle.

If you wanted a polished NiB you should have bought a Spikes, but there not "match grade" or if you wanted a perfect looking one could have bought a ares armor bcg they are very "purty".

[kravman4]

Those are only cosmetic flaws.

Wear points are bottom of carrier that resets hammer and guide rails, as well as where it contacts charging handle.

If you wanted a polished NiB you should have bought a Spikes, but there not "match grade" or if you wanted a perfect looking one could have bought a ares armor bcg they are very "purty".

My #1 goal is durability/reliability. It seems like the question of the plating being OK has been laid to rest. I understand the "match grade" concept of matching a bolt face to the barrel extension, but if the bolt/carrier is held to tighter tolerances and has better components, then I'm good with it. Will report back after I've had some range time.