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1/15/2017 12:10:36 PM EDT
Built a new retro-esque carbine using the Brownells retro barrel. Shot it yesterday. First mag ran perfect. Second started to double feed. By the end of the 3rd mag it was double feeding every shot. Tried it on another lower with an H buffer, same thing. When I got home I noticed that there is fouling all over the front of the gas tube (BCM). I took off the gas block also to check alignment of the gas port, the alignment looked good. Do you think my Brownells gas block was faulty? Using a PSA Premium BCG by the way, brand new.
1/15/2017 12:17:11 PM EDT
[#1]
Quoted:
Built a new retro-esque carbine using the Brownells retro barrel. Shot it yesterday. First mag ran perfect. Second started to double feed. By the end of the 3rd mag it was double feeding every shot. Tried it on another lower with an H buffer, same thing. When I got home I noticed that there is fouling all over the front of the gas tube (BCM). I took off the gas block also to check alignment of the gas port, the alignment looked good. Do you think my Brownells gas block was faulty? Using a PSA Premium BCG by the way, brand new.
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More specifics. What ammo? Which magazine(s)?
1/15/2017 12:25:05 PM EDT
[#2]
Hello! Used AR5.56 American Eagle and a couple of brand new Okay Ind USGI, a NHMTG(?) and a Colt USGI. All same issues. Never seen so much fouling on a gas tube.
1/15/2017 12:30:45 PM EDT
[#3]
Quote History
Quoted:
Hello! Used AR5.56 American Eagle and a couple of brand new Okay Ind USGI, a NHMTG(?) and a Colt USGI. All same issues. Never seen so much fouling on a gas tube.
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In lieu of that, I would not say that the ammo or the magazines are the issue. Which receivers are you using? Feedramps?
1/15/2017 12:35:48 PM EDT
[#4]
The Brownells retro has rifle feed ramps. The Anchor Harvey A1/C7 is not an M4 receiver. So that is not an issue.

ETA: at least it shouldn't be. Lol
1/15/2017 12:40:41 PM EDT
[#5]
Quote History
Quoted:
The Brownells retro has rifle feed ramps. The Anchor Harvey A1/C7 is not an M4 receiver. So that is not an issue.

ETA: at least it shouldn't be. Lol
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You are right, it should not be. You may want to try a different BCG or just a different bolt and see if that changes anything.
1/15/2017 12:45:11 PM EDT
[#6]
That's a good call. I will try that. I also changed the lube from Slip2000 to TW25b paste to see if fouling was from lube. Other than that, all I can think is that it's an out of spec Gas Block and that gas is bleeding from the gas tube rather than being directed back to the chamber.
1/15/2017 2:39:49 PM EDT
[#7]
when you say double feed, do you mean there are 2 live rounds jammed? Or a live and a spent?  The first (2 live) would be a mag issue, the second would be a short-stroke, under gas issue which would be consistant with the blow-by at the gas block. Was the bolt locking back on the last round?
1/18/2017 2:16:08 PM EDT
[#8]
Quote History
Quoted:
when you say double feed, do you mean there are 2 live rounds jammed? Or a live and a spent?  The first (2 live) would be a mag issue, the second would be a short-stroke, under gas issue which would be consistant with the blow-by at the gas block. Was the bolt locking back on the last round?
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This^

Try some PMC XTAC that stuff is hotter than the Federal in my experience.
1/21/2017 5:35:17 PM EDT
[#9]
Quote History
Quoted:
This^

Try some PMC XTAC that stuff is hotter than the Federal in my experience.
View Quote View All Quotes
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Quote History
Quoted:
Quoted:
when you say double feed, do you mean there are 2 live rounds jammed? Or a live and a spent?  The first (2 live) would be a mag issue, the second would be a short-stroke, under gas issue which would be consistant with the blow-by at the gas block. Was the bolt locking back on the last round?
This^

Try some PMC XTAC that stuff is hotter than the Federal in my experience.


Thanks guys! I am thinking the Brownells retro gas block is faulty. It's spitting too much gas all over the tube. I am going to see what their customer service says. Failing that I will get another.
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