AR bolt face, wear after how many rnds?

[majtii]

Got a new rifle today. Sold as brand new from dealer but there is carbon all over the bolt. The bolt face has also a nice carbon ring from the primer.
Feeling with a toothpick the face is slightly eroded, I can feel the edges.

After how many rounds does the etched ring from the primer appear?

 

[Red_SC]

Here's a good resource:

How to Determine the Round Count on a used AR-15

A lot of the original photos are gone, but the ones remaining are helpful.

 

[MarkCO]

If there is significant bolt face erosion, in a ring from the primer, likely the bolt is bad or the ammo was bad. I have seen that occur in as little as 20 rounds. If everything is good, you should not see erosion until past about 10K.

I would be heading back to the dealer ASAP!

 

[HKpirate]

well regardless if you bought this as a new product and it is clearly used id be making a trip back to the store. I would not be concerned with how many rounds as to why I bought a firearm under the assumption that it was in fact " new ". Pictures would help a great deal but it does not sound like a once fired test shot from factory.

 

[Evolution 9]

Which brand of AR?

Some of the better ones do extensive test firing (LMT comes to mind), often resulting in claims of the gun being used, when in fact, it's just evidence of rigorous QA/QC by the maker.

Corrosion and carbon ring buildup are easy to mistake for one another. Clean it well before trying to determine which one it is (if it cleans up smooth, it's just buildup).

 

[majtii]

Some quick pics of boltface/extractor and cam pin.

 

[Evolution 9]

Those pics aren't enough info. That could easily be factory test firing if the gun is from a manufacturer that test fires the guns.

What brand of gun is it? Without that info, opinions of two tiny pictures will be worthless.

 

[MPD142]

Which brand of AR?

Some of the better ones do extensive test firing (LMT comes to mind), often resulting in claims of the gun being used, when in fact, it's just evidence of rigorous QA/QC by the maker.

Corrosion and carbon ring buildup are easy to mistake for one another. Clean it well before trying to determine which one it is (if it cleans up smooth, it's just buildup).

I agree, from the LMT's I have seen they must run 50 rounds or more through the rifles to test them/break them in. When my 308 MWS arrived at the gun shop and I broke it down I was amazed at the amount of "wear" and carbon inside the rifle. I would guess they ran at least 50 rounds through the rifle before shipping it out. Their 5.56 guns I've seen showed the same thing but not as bad as my 308.

 

[majtii]

Don't want to hang out brand or dealer before I've talked to them. Just want get some opinions whether the gun have run 25 rounds or 250.
All guns I've bought before have all been shiny and clean.

 

[Evolution 9]

Don't want to hang out brand or dealer before I've talked to them. Just want get some opinions whether the gun have run 25 rounds or 250.
All guns I've bought before have all been shiny and clean.

Then as stated, we can't help you.

 

[hotbrass]

Looks normal for a new gun.

 

[-Nick-]

Don't want to hang out brand or dealer before I've talked to them. Just want get some opinions whether the gun have run 25 rounds or 250.
All guns I've bought before have all been shiny and clean.

Why? You want answers but you don't want anyone to know the facts ie the truth? No one would blame a manufacturer for a shop selling a used firearm if that is the case and if it's just from a few test rounds out of a quality company then there's still no issue...

 

[Tangodown911]

I agree. Just spit it out...