Sectioned AR15 Barrel

[*MALICE*]

Had this barrel sitting in the bottom of my tool box for a while.

It is a 10.5" Norinco barrel. The rifle was used for 'new shooter groups', so it had a VERY high round count. This was a 'club'/'beater' gun. It was not cleaned more than necessary. This rifle was always being fixed. It had a very obnoxious muzzle brake on it.

The rifle was shot at ~15-25 yards for most of it's life so accuracy was never a huge concern.

It was over-gassed from new but got worse over time. Ejection (over time) advanced to around 2 o'clock, it began sheering lugs more often, so an adjustable gas block was added. That noticeably improved bolt life.

Many (many) parts were replaced over time on the rifle. I think ultimately the only original parts are the upper and lower receiver, buffer tube, stock, take down pins, selector, and the grip. I think almost everything else had been changed out at some point.

Barrel was replaced somewhere around 100k* rounds because it was consistently keyholing at 15 yards. Yes. They put that many rounds through it.

So who wouldn't be curious what it looked like inside??

*round count estimated based upon average weekly usage

 

[mac100]

That’s pretty cool. Looks like throat erosion is massive. Projectile doesn’t engage rifling for 6” or so. Wow!

 

[*MALICE*]

The gas port erosion is crazy.

It erodes forward (I would have thought it would do it towards the breech), and it's not clear in the photo, but the erosion channel is slightly 'fluted?'.

I was surprised that there's no erosion between the muzzle and the brake, but once it reaches the gills of the brake (and reaches oxygen?), it becomes dramatic

 

[Daver_II]

And some here say norinco won't function... 100k rounds of proof

Granted... if someone handed me a beater gun that worn in I would question its integrity.

 

[*MALICE*]

And some here say norinco won't function... 100k rounds of proof

Granted... if someone handed me a beater gun that worn in I would question its integrity.

In fairness......it can't really be said a norinco made it that many rounds. Most of the major components had been changed over time.

 

[*MALICE*]

A note. The muzzle brake was only on the barrel maybe 2/3 of its life.

 

[griffin86]

Cool

 

[B-N]

That's crazy!

The erosion at the gas block wasn't something I had thought about before.

 

[Scotty454]

I think the gas port erosion surprised me the most... It's fairly well known that brakes are a wearable part if you run enough rounds through them, throats will erode over time, but damn, that gas port erosion is over half the wall thickness!

 

[pauls]

retired it too early...
A little longer and you could have just re-chambered it for 6 ARC and kept going.
Once you get to 300blackout, then it may be time to let it rest...

 

[*MALICE*]

retired it too early...
A little longer and you could have just re-chambered it for 6 ARC and kept going.
Once you get to 300blackout, then it may be time to let it rest...

Lmao

 

[8 ball]

Cool! Thanks for sharing!

 

[Mightymoose410]

Super cool

 

[ISaidShotgun!]

Thanks for sharing. Really interesting.

 

[Mosin_redstar]

Great post! Was very cool to see the erosion on the inside, I've always wondered what that looks like after such a high round count! Thanks for sharing!

 

[diegocn]

Other than what has already been stated, I was surprised the front sight block pin slot was drilled so deep. It almost took away 2/3 of the barrel wall thickness. Wonder how thin of a barrel you can really turn it down to on 223.

 

[DT741]

Other than what has already been stated, I was surprised the front sight block pin slot was drilled so deep. It almost took away 2/3 of the barrel wall thickness. Wonder how thin of a barrel you can really turn it down to on 223.

Seeing 14.5" pencil barrels we use to have on C8s, I say pretty thin.


OP: thanks for sharing, very interesting

 

[*MALICE*]

Other than what has already been stated, I was surprised the front sight block pin slot was drilled so deep. It almost took away 2/3 of the barrel wall thickness. Wonder how thin of a barrel you can really turn it down to on 223.

I'm not 100% sure what happened there and The guy who owns it seemed a little fuzzy on the details. The first time I worked on the rifle, I had to take the chopped fsb because the gas tube burnt off inside and I noticed there was some weld on it......so I have a theory:

I have a suspicion that his father tried to remove the original taper pins, didn't know what he was doing and was either hitting them from the wrong side or wasn't supporting the gas block properly and the force wasn't being imparted onto the pin correctly............and then when he couldn't get it out, got the drill bit out. After it was re-installed it looked like an abortion, so they put some weld on the gas block to hide the extra holes lol

I don't think it came from china like that

 

[OkayShooter]

That brake wear, is impressive.

 

[*MALICE*]

I'll try and get a picture of the cam pin 'scar' on the inside of the upper. It's pretty substantial too