Even Known Good Companies Can Produce Garbage

[HKGuns]

I found an FN barrel on sale at Midway for $188. Looked like a screaming deal on a known good barrel, so I snagged one. I posted it in the good deals thread and when I tried to post a link, it was gone.

This is the sticker on the box, it came in a sealed Metal-Guard plastic sleeve.



When I went to install the gas tube it was short. I had a carbine length tube in stock and it didn’t even make it to the hole in the upper.

This raised some red flags as it is clearly marked carbine gas, yet when I measured, sure enough it’s a mid length. No issue for me as either will work when properly gassed.

Next step was to gauge the gas port. Turns out it was smaller than my smallest pin gauge of .061, no way that would cycle a mid length gas system.

What to do? I figured if I return it I won’t get another barrel and I had already dimpled the side opposite the gas port, so I decided to try and carefully drill out the gas port to .077 which is the closest I could get with a bit I own.



I went slowly, with a new bit, using my Bosch hand drill. (I don't have a drill press at this house, but I have several at another.) It went perfectly, I was able to stop before punching through and hitting the inside of the barrel. I scoped the inside of the barrel and the inside of the hole is extremely clean and free of any burrs.

Guaged it again and it measured .077 which should cycle perfectly once my mid-length gas tubes arrive.

Bottom line here is to have the tools on hand to check and fix your shit. Even the best companies can produce garbage, at times.

[mack7.62]

Button rifled means it was not CHF, so aftermarket? What are the markings?

[HKGuns]

Button rifled means it was not CHF, so aftermarket? What are the markings?

The button rifling doesn’t bother me much as I already have a bunch.

The only other marking is 556 NATO stamped near the muzzle.

[17K]

You had a good opportunity to get the perfect port size and you hogged it out with a hand drill.

Way to go.

[markm]

You had a good opportunity to get the perfect port size and you hogged it out with a hand drill.

Way to go.

.077" isn't bad for a middy at all assuming no suppressor attached. Even then it wouldn't be terrible.

[T2C]

I am curious. Why would you enlarge the gas port size before assembling and shooting the weapon?

[markm]

.061" would be very lean for a middy. That said, I would not be using a hand drill. And I would have started with a reamer around .073" or so. But the known port size for middy is .076-.080"

[HKGuns]

I am curious. Why would you enlarge the gas port size before assembling and shooting the weapon?

Because .061 wasn’t close to fitting, so that port was probably .057ish and I saw no good reason to assemble it in that state.

No way it would have cycled properly at that size.

[georgeib]

Because .061 wasn’t close to fitting, so that port was probably .057ish and I saw no good reason to assemble it in that state.

No way it would have cycled properly at that size.

Interesting. Might have been some special run they did for someone exclusively for suppressor use.

[markm]

With the mislabel and wrong tube? I think they just are suffering from what many companies are these days.... Imbecile employees.