New mk18 gas port size?

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[ARCHIVED THREAD] - New mk18 gas port size?

Posted: 7/7/2017 10:08:54 AM EST

I am hearing rumors that DD is changing the gas port size on the mk18 to 0.072. I was wondering if someone from DD can confirm this.

Posted: 7/9/2017 8:15:42 PM EST

[#1]

I'd be interested in this information. Still waiting on my form 4. I can hope for a retro-fit with an MK12 gas block.

Posted: 7/9/2017 8:26:15 PM EST

[#2]

If it's true I'll be filing a form 4 by the end of the week.

Posted: 7/23/2017 9:11:11 PM EST

[#3]

Anyone know where to find a Mk18 URG with the properly spec'd .072 GAS PORT?

Posted: 7/23/2017 9:44:43 PM EST

[#4]

I am still waiting on an official response, but the word on the street is if you buy one with the old gas Port they will replace the barrel free of charge.

Posted: 7/24/2017 12:13:55 AM EST

[#5]

Please update when you hear back.

Posted: 7/25/2017 5:58:17 PM EST

[#6]

Quote History

Quoted:
I am still waiting on an official response, but the word on the street is if you buy one with the old gas Port they will replace the barrel free of charge.

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Would love to hear more about this. Would thus apply to a complete MK18 upper, or entire SBR only?

However, even though it's gassy, I've never had an issue with my MK18, and i shoot it suppressed half the time.

Posted: 7/25/2017 11:47:33 PM EST

[#7]

Quote History

Quoted:

Would love to hear more about this. Would thus apply to a complete MK18 upper, or entire SBR only?

However, even though it's gassy, I've never had an issue with my MK18, and i shoot it suppressed half the time.

View Quote

My understanding is both?

Posted: 7/26/2017 1:13:25 AM EST

[#8]

Quote History

Quoted:
Anyone know where to find a Mk18 URG with the properly spec'd .072 GAS PORT?

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.070 is the proper spec for the gas port on a MK18 URG.

Posted: 8/4/2017 12:04:39 PM EST

[#9]

^^^^ this.

Posted: 8/17/2017 8:13:29 PM EST

[#10]

FYI I received 3 10.3 barrels from DD yesterday, ports .070 on all 3.

Posted: 8/18/2017 9:20:00 AM EST

[#11]

Quote History

Quoted:
FYI I received 3 10.3 barrels from DD yesterday, ports .070 on all 3.

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To piggyback on that I received an E-mail response a week or so ago from DD stating commercial size on all Mk18 barrels/URGs/SBRs is .070.

Posted: 8/20/2017 1:13:25 PM EST

[#12]

Quote History

Quoted:
FYI I received 3 10.3 barrels from DD yesterday, ports .070 on all 3.

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Is there anyway to verify the gas port size via UPC or anything? I was planning on ordering a 10.3 from Brownells but don't want to get stuck with the big ass old port size

Posted: 8/22/2017 7:14:01 AM EST

[#13]

Curious as well. On how to know what I'm gettting. I'm wanting a Mod 1 upper and would prefer proper gas port size.

Posted: 8/24/2017 7:01:56 PM EST

[#14]

Gonna write DD an email to see if there is a way to verify which gas port one would have. Maybe there is a date or timeframe to go by.

Posted: 8/26/2017 12:21:29 AM EST

[#15]

Quote History

Quoted:
Gonna write DD an email to see if there is a way to verify which gas port one would have. Maybe there is a date or timeframe to go by.

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Looks like the gas port was changed to 0.070" at the end of this June.

Posted: 8/26/2017 7:02:37 AM EST

[#16]

Quote History

Quoted:

Looks like the gas port was changed to 0.070" at the end of this June.

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I believe it was changed to 0.072 at some point last year as a member on TOS started a thread on it and actually measured his gas port with pictures (closer to 0.073, but DD spec'd it at 0.072), previous to that it was 0.080.

Posted: 8/26/2017 7:47:24 AM EST

[#17]

I've had an MK18 for 3 years.

Never a FTF or FTE with tons of use.

Whats the the issue with the gas port size?

Posted: 8/26/2017 9:30:17 AM EST

[#18]

To large causing excess gas to the face when suppressed.

Posted: 8/26/2017 9:49:41 AM EST

[#19]

Quote History

Quoted:
To large causing excess gas to the face when suppressed.

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Also excessive wear in critical components such as the bolt and extractor.

Posted: 8/26/2017 6:58:24 PM EST

[#20]

Anybody know of the stripped uppers through brownells where all smaller gas port?

Posted: 8/27/2017 8:19:34 PM EST

[#21]

This thread could use a response from joe marler

Posted: 9/1/2017 7:23:59 PM EST

[#22]

This is the email I also got back from them a while back. As always, stellar customer service from Daniel Defense.

Cheers

"Thank you for contacting Daniel Defense.

We have made an inline change to the gas port diameter on all 5.56 10.3 barrels manufactured. This change was effective on all barrels manufactured after June 2017. As always, all of our products are backed by our Lifetime Warranty. If you are having any malfunctions or failures, we will be happy to get the product back in house free of charge for an evaluation then make the necessary repairs to get the product running as it should.

Thank you, again, for contacting us and if you have any questions please let me know."

Posted: 9/3/2017 1:06:50 PM EST

[#23]

Nice to know that they changed it, since so many people considered it a major flaw of an otherwise awesome upper/rifle. I can honestly say that shooting mine built in 2015 with a suppressor I have never found it to be a problem.

Posted: 1/28/2018 12:19:15 PM EST

[#24]

So, I bought mine in August 2017 but it has an inspection tag from March 2017.

This means it doesn’t have the .070 port?

I saw posts in the Mk18 thread from back in May from a guy that said his was .070 when he checked it???

Posted: 1/28/2018 7:01:46 PM EST

[#25]

How I have managed to shoot so much with the larger gas port I will never know.

Posted: 1/28/2018 7:11:58 PM EST

[#26]

Quote History

Quoted:
How I have managed to shoot so much with the larger gas port I will never know.

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Posted: 1/29/2018 10:46:33 AM EST

[#27]

I just spoke to Daniel Defense and the guy there said, as far as he knows, all of the Socom barrels have a .071 gas port no matter when manufactured.

He reminded me they have a 100% lifetime guarantee, so if there are ever any issues with it I don’t need to worry.

Posted: 1/29/2018 2:53:27 PM EST

[#28]

Quote History

Quoted:
How I have managed to shoot so much with the larger gas port I will never know.

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This. I have no plans to send mine in unless I start having issues.

Posted: 1/29/2018 4:40:45 PM EST

[#29]

Quote History

Quoted:

This. I have no plans to send mine in unless I start having issues.

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Interestingly enough, I called technical support again and got a different person who said the 10.3” barrels would not be the newer .071 port size if you have an inspection date prior to June 2017.

Now I’m confused...guess it’s time to give up and just shoot it.

Posted: 2/4/2018 11:18:39 PM EST

[#30]

From what I have seen, the barrels after August of 2017 are at 0.070". It could be, like said, that the date is June. I can just verify that from August forward, all is good. Prior to "Summer" of 2017, the gas port was much larger, and posed some issues for some people.

Posted: 2/26/2018 7:31:58 PM EST

[#31]

I have two barrels from 2013. Would be nice to get some of the gas to face cut down with properly sized gas ports.

What's the best way to measure the gas ports?

Posted: 2/27/2018 5:05:48 AM EST

[#32]

Pin gages, but calipers will work just fine.

Posted: 3/22/2018 7:00:23 AM EST

[#33]

Quote History

Quoted:
I have two barrels from 2013. Would be nice to get some of the gas to face cut down with properly sized gas ports.

What's the best way to measure the gas ports?

View Quote

I bought pin gauges for this. You can buy them individually from Amazon so you don't need to get ALL of them in a set, just a couple in the sizes you require.

Posted: 3/22/2018 9:34:57 AM EST

[#34]

Quote History

Quoted:
I have two barrels from 2013. Would be nice to get some of the gas to face cut down with properly sized gas ports.

What's the best way to measure the gas ports?

View Quote

others answered your question of how to measure. For me, calipers are not good for this, or it might be OE (operator error). I get within +/- 0.008, but with gas ports, you are measuring such a small opening, that is a wide margin. Pin guages get you to +/- 0.0005, or better than 10X the accuracy.

As to how to address the issue of an over-sized gas port, you need to first assess if it really matters. Are you having problems? If not, fogetaboutit. If you are, then you can buy new barrels for $250 to $290 each, or have the gas port plugged and re-drilled, probably at 90 degrees off center, give or take. This means that your barrel extension needs to be removed and a new one installed, headspaced and pinned. For only two barrels, that will likely cost you around $150 per barrel, give or take $40. I have a good source for that, if you want to go that route. If you go that route, really depends upon budget and how new the barrels are.

You can always call DD and ask them to replace. Not sure what they would say. I imagine if you can show issues, they would be more sympathetic.

[ARCHIVED THREAD] - New mk18 gas port size?

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