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2/16/2016 10:26:57 PM EDT
This has probably been asked. But I could not find the thread.



I am in the market for another sbr. I was pretty dead set on an LMT 10.5, but after a little reading I am starting to question my original decision. I am now looking at the DD Mk18.




I'm reaching out to any owners of this rifle to see if they are still pleased with their purchase. Any owners of the LMT are more than welcome to add as well.  The LMT is said to not have a full-auto bolt carrier. Which I don't like. Also it is not mil-spec (not to terribly important) and heavier that the DD.




Also the last request. Anyone running the DD suppressed, what can are your running? It says there are some that will not mount per the rail length. I have a kac can coming for my kac 11.5. But I will be buying another can to dedicate on this rig.




I appreciate any input.
2/16/2016 10:36:17 PM EDT
[#1]
What exactly are you looking to get out of it?  Do you want some sort of authenticity?  Because if not, there are plenty of good 10.5 uppers you can get.
2/16/2016 11:06:57 PM EDT
[#2]
I have one and like it. I was going for a clone which is why I got it rather than buying one of the other brands out there that being said I looked really close at LMT and PWS. Overall mine runs great, never had a malfunction and shoot mostly m193 and m855 unsurpressed. You might here complaints about the gas block and over gassing with suppressors but I don't have an opinion on the matter.
2/16/2016 11:19:33 PM EDT
[#3]
I own an MK18 and love it.



That being said I'd lose no sleep if it were replaced by an LMT equal.




Both are great guns.
2/16/2016 11:19:53 PM EDT
[#4]
Give me a month and I'll tell you.  I've got an LMT MRP with a 16" barrel awaiting Form 1 approval to put on the 10.5".  I will be shooting it both suppressed and unsuppressed.

2/17/2016 12:09:50 AM EDT
[#5]
I'll agree with the post about cloning. If you're not going for a clone, LMT is top notch. My first SBR was an LMT complete lowerr
2/17/2016 1:24:00 AM EDT
[#6]
I love my DD mk 18
2/17/2016 1:31:15 AM EDT
[#7]
Unless your building a clone I would look at some of the other options available. I thought about doing a MK18 but honestly there are other setups that were better suited to my needs/wants.
2/17/2016 7:22:29 AM EDT
[#8]

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Unless your building a clone I would look at some of the other options available. I thought about doing a MK18 but honestly there are other setups that were better suited to my needs/wants.
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Which 10.3"/10.5" guns would you be referring to that are better than what LMT/DD sell?




Not "as good" but better.....what would those be?
2/17/2016 7:32:29 AM EDT
[#9]
Quote History
Quoted:

  Which 10.3"/10.5" guns would you be referring to that are better than what LMT/DD sell?


Not "as good" but better.....what would those be?
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Quoted:
Quoted:
Unless your building a clone I would look at some of the other options available. I thought about doing a MK18 but honestly there are other setups that were better suited to my needs/wants.

  Which 10.3"/10.5" guns would you be referring to that are better than what LMT/DD sell?


Not "as good" but better.....what would those be?



I'd buy a second KAC before either...but that's just me.

OP...FWIW...a FA vs Semi bolt carrier doesn't really mean much either way on a semi...so I wouldn't worry too much.
2/17/2016 7:42:58 AM EDT
[#10]
I appreciate all the post. I could care less about the clone aspect. This is just another sbr. I'm not going for kac again as I cannot locate another mod 1 sbr. I also am only buying factory SBR's, no builds. I could list applications I would use this for. But as most of us, just just running drills and classes.
From the post above, those that have it, like it. But not enough to keep it, if offered a LMT/PWS. Any of specific reasons, other than over gassed when suppressed. Or is it just general overall quality that the LMT could provide over the DD?
2/17/2016 11:15:35 AM EDT
[#11]

Quote History
Quoted:


I appreciate all the post. I could care less about the clone aspect. This is just another sbr. I'm not going for kac again as I cannot locate another mod 1 sbr. I also am only buying factory SBR's, no builds. I could list applications I would use this for. But as most of us, just just running drills and classes.From the post above, those that have it, like it. But not enough to keep it, if offered a LMT/PWS. Any of specific reasons, other than over gassed when suppressed. Or is it just general overall quality that the LMT could provide over the DD?

View Quote




 
I put my MK18 upper on a KAC ambi lower.




Perfect combo IMO
2/17/2016 11:29:15 AM EDT
[#12]
I've been using a DD mk18 barrel on a sorta clone build with a surefire can. I thought about using a microMOA adjustable gasblock with it, but it hasn't had any issues other than being overgassed. I'm using an H2 buffer and a blue springco spring with it as well.




2/17/2016 3:59:07 PM EDT
[#13]
Run my DD MK 18 with a fail zero m16 bolt suppressed and unsuppressed. Runs like a boss. Using Omega can, all stock except bolt and raptor CH, blowback less than with my PSA.
2/17/2016 5:14:31 PM EDT
[#14]
Thanks for the post about the cans.

I went ahead and ordered my Mk18 today. from what I'm seeing it will do everything that I want to do. Now i just need to decide What can I am going to Run. I really dont see me getting a Surefire can, nothing against them, just not what I want. I may look at Rugged or SiCo.
2/17/2016 5:18:00 PM EDT
[#15]
Buddy has a Mk18.  Has a Mini-4 on it.  It has run fairly reliably with the can.  Blowback is noticeable, and he has had some issues with gas rings on the bolt blowing a few times, but I'm not sure if that's a gas issue or a BCG issue.

Cousin has an LMT MRP 10.5 upper.  It has not been shot as much as the MK18 described above so I can't make a fair reliability comparison, but I am not aware of it having any malfunctions to date.  I do strongly prefer the slimmer rail profile on that upper.

I think you're GTG with either choice.
2/17/2016 5:34:38 PM EDT
[#16]
I have a DD MK18 with KAC NT4 suppressor and love the combo. I mainly shoot m193 & m855 ammo and run this gun hard as hell and it just performs. Would buy another in a heartbeat." />
2/17/2016 5:36:27 PM EDT
[#17]
This is the information you seek...

http://www.ar15.com/forums/t_3_118/641240_Official_Mk_18_and_CQBR_Photo_and_Discussion_Thread.html
2/17/2016 7:22:52 PM EDT
[#18]

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I have a DD MK18 with KAC NT4 suppressor and love the combo. I mainly shoot m193 & m855 ammo and run this gun hard as hell and it just performs. Would buy another in a heartbeat.http:// <a href=http://i1301.photobucket.com/albums/ag115/Dan_Petrecca_III/20150815_115324_zpsjml5ubyp.jpg</a>" />
View Quote




 
I would love to get a NT-4 for this rifle. But funds and me wanting to cheat are keeping from it.

I am going to get a 30cal can for the mk18.  But I am needing to cover a few bases with this can.

I am looking at both the rugged razor and SiCo omega.




But at the end of the day, yours will kill mine with that NT-4
2/17/2016 9:04:59 PM EDT
[#19]
My friend has an LMT and I have the DD Mk18 running with a surefire socom suppressor. The Mk18 is over gassed but can be managed any number of ways if that sorta thing bothers you, that being said I would not hesitate to buy another Mk18 if I was getting another AR.
2/17/2016 9:27:57 PM EDT
[#20]
I love my DD MK18, With DD you are also purchasing the best customer service in the business.
2/17/2016 9:48:08 PM EDT
[#21]
Either one you will be happy with so buy which one you want and shoot the piss out of it.

I have a lmt 10.5 and couldn't be happier. It's my go to truck/bedside/hunting/shtf/plinker.
2/18/2016 12:51:35 AM EDT
[#22]
Get both



I chose to build my own mk18 upper because factory dd is overgassed. I have always wanted an let 10.5 though.
2/18/2016 7:16:50 AM EDT
[#23]

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Quoted:


Get both



I chose to build my own mk18 upper because factory dd is overgassed. I have always wanted an let 10.5 though.

View Quote




 
Factory DD MK18's are over gassed?




Mine runs on every single type of ammo I've ever run through it.




It's as reliable from the factory as every one of my other AR's.




The gas port is slightly larger then the .mil guns to accommodate a wider range of ammo types.....which it does exceptionally well.
2/18/2016 11:14:47 AM EDT
[#24]

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Quoted:





  Factory DD MK18's are over gassed?





Mine runs on every single type of ammo I've ever run through it.





It's as reliable from the factory as every one of my other AR's.





The gas port is slightly larger then the .mil guns to accommodate a wider range of ammo types.....which it does exceptionally well.

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Quoted:



Quoted:

Get both



I chose to build my own mk18 upper because factory dd is overgassed. I have always wanted an let 10.5 though.



  Factory DD MK18's are over gassed?





Mine runs on every single type of ammo I've ever run through it.





It's as reliable from the factory as every one of my other AR's.





The gas port is slightly larger then the .mil guns to accommodate a wider range of ammo types.....which it does exceptionally well.

You don't shoot suppressed or you don't know what a properly gassed rifle is like. A gun can run fine and be overgassed, but a .083 port is to large regardless.
2/18/2016 12:34:15 PM EDT
[#25]
Just curious, anyone who has the Mk18, and thinks its overgassed. Have
you tried a Pri Gas buster, if so, does it make a difference.  

 
2/18/2016 2:07:16 PM EDT
[#26]
I have a DD. I love it. That being said I can't compare it to an LMT. The only time I would consider it over gassed is when firing mil spec 5.56. If you plan on shooting 223 you should be good - the larger gas port is for handling both weaker .223 and hotter 5.56 loads.
2/18/2016 2:31:26 PM EDT
[#27]


Quote History
Quoted:



Just curious, anyone who has the Mk18, and thinks its overgassed. Have you tried a Pri Gas buster, if so, does it make a difference.    
View Quote
Going to a gas deflecting charging handle is addressing the symptoms of overgassing and not the cause.





Being 'overgassed' is 'relative' to the conditions.





First some facts.


1.  A true milspec MK18 is ported to .070".  This is mentioned on page 4 of this document: http://www.dtic.mil/ndia/2003smallarms/john.ppt


2.  A true issue MK18 is actually sourced from Colt and ported to .070 not sourced from DD.  


3.  However, DD does make MK18 barrels and they do two different port sizes.  They do a milspec ported barrel (.070) which is typically not available on the commercial market however a bunch are out there that Western Sports was selling several months ago.  Their commercial spec barrel is ported at .081/.082".  I say two different sizes since if you look at a numbered drill bit chart those sizes are standard numbered bit sizes: http://bobmay.astronomy.net/misc/drillchart.htm





DD is not stupid and they don't want to deal with people sending barrels back if they won't run with commonly available steel cased ammo.  


They know that if they ported ALL of their MK18 barrels to milspec .070 they would get returns.


A military issue MK18 rifle will probably never see Tula in its chamber.





I've taken new DD MK18 barrels and was able to stick the shank of a .082 bit inside the port while I've also heard DD support say they were actually drilled to .081...but bits can drill oversized and we are only talking .001"





Is a commercial spec DD MK18 barrel (ported .081/.082) overgassed when shooting Tula with an H2 buffer?  Probably not.  


Is the same rifle overgassed when using LC M855?  Yes.





This is a good read: http://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/






Tula most likely uses the same powder in their 556/223 loading as their
7.62x39 loads which burns fast and by the time the bullet passes the
port the pressure has already gone down.


So a larger gas port is required for it to function and not have a return.





As mentioned here: http://www.recoilweb.com/micromoas-govnah-adjustable-gas-block-38489.html


"If
you can run imported steel-cased ammo without any special
modifications, your rifle is over gassed when using quality brass."





Yes, I'm in the business of selling adjustable gas blocks but I am NOT saying an adjustable gas block is required.





As you can see in the video below.  The MK18 is shown firing full auto 10 rounds with the factory commercial .081/.082 port then switched to .049 suppressed.


In the video, you can see that in both modes the rifle functions 100% reliable so NO, you don't  NEED an adjustable gas block, gas key, carrier or special upper....





However, it is obvious to FEEL the benefits.  If you look at the video you can see how much more the shooters arm vibrates when running the full gas vs optimal gas.


Recoil is greater when not controlling the gas.  It is much easier to get back on target faster when you have the softer, smoother recoil impulse when using the proper amount of gas.


Less fouling is coming into the action when controlling the gas.  So that means more rounds can be put down range before you have to clean or fouling gets so bad you start to have malfunctions.  This is something no special charging handle, buffer or springs can help with.  


Also consider that if you have a suppressed mode and run the gun so much that you need more gas, you can always increase the gas to keep running.  No adjustable means no option.











Everyone is different and have different criteria for their needs.  


I remember when I got my first 556 suppressor back in 1998 and thought this sucks from the backpressure and overgassing and didn't shoot it much since it was an unpleasant experience while some people seem oblivious to it.


I would recommend that you try your MK18 as is and see what you think when you suppress it.  





 
2/18/2016 2:39:33 PM EDT
[#28]
Quote History
Quoted:

  Factory DD MK18's are over gassed?


Mine runs on every single type of ammo I've ever run through it.


It's as reliable from the factory as every one of my other AR's.


The gas port is slightly larger then the .mil guns to accommodate a wider range of ammo types.....which it does exceptionally well.
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Quote History
Quoted:
Quoted:
Get both

I chose to build my own mk18 upper because factory dd is overgassed. I have always wanted an let 10.5 though.

  Factory DD MK18's are over gassed?


Mine runs on every single type of ammo I've ever run through it.


It's as reliable from the factory as every one of my other AR's.


The gas port is slightly larger then the .mil guns to accommodate a wider range of ammo types.....which it does exceptionally well.

Exactly. That means it's over gassed
2/18/2016 5:51:08 PM EDT
[#29]
Thank you amphibian for the Information. Once the Mk18 is here, i will determine what (if anything) is needed. it is good to know that if i feel that there is a problem, that there is a solution.  

2/19/2016 8:49:03 PM EDT
[#30]
I run my Mk18 (factory upper on registered DD lower origonally from a M4v3) suppressed with an AAC SDN-6. There is but a freaking paper width between the can and rail, but it does clear and never touches. So far 200 rounds over the snowy winter no issues, about 160 suppressed. I did switch from a gunfighter to a PRI gasbuster, honestly I don't think it made much of a difference, but I MUCH prefer the gunfighter latch to the PRI. I'm running mine with a H2 buffer and a +10% spring. With M855 unsupressed ejection is perfect, suppressed its over gassed chucking casings at 1:30-2 o'clock, hasn't cause an issue so far but the most I've managed in one sitting is 60 rounds.
2/19/2016 11:54:27 PM EDT
[#31]
Those of you who have DD MK18's - do they have pinned gas blocks? DD's website says they are, but if you go to order a MK12 gas block from their site, it uses set screws. Looks like the KAC Lo-Pro (MK12) gas block uses set screws, also.
2/20/2016 12:19:39 AM EDT
[#32]
Quote History
Quoted:
Those of you who have DD MK18's - do they have pinned gas blocks? DD's website says they are, but if you go to order a MK12 gas block from their site, it uses set screws. Looks like the KAC Lo-Pro (MK12) gas block uses set screws, also.
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It's pinned on mine. Single pin, has a place for a set screw but not installed.
2/20/2016 1:04:15 AM EDT
[#33]
Quote History
Quoted:



It's pinned on mine. Single pin, has a place for a set screw but not installed.
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Quoted:
Quoted:
Those of you who have DD MK18's - do they have pinned gas blocks? DD's website says they are, but if you go to order a MK12 gas block from their site, it uses set screws. Looks like the KAC Lo-Pro (MK12) gas block uses set screws, also.



It's pinned on mine. Single pin, has a place for a set screw but not installed.


Yep they are pinned
2/20/2016 10:55:01 AM EDT
[#34]
Quote History
Quoted:
Just curious, anyone who has the Mk18, and thinks its overgassed. Have you tried a Pri Gas buster, if so, does it make a difference.    
View Quote


I've got a couple factory DD Mk18 uppers and run Surefire cans.  My "perfect" config is a gas buster, a Springco red spring, and an H3 buffer.  Runs with or without the can even with steel crap and no gas to the face.  I like not having to mess with my rifle, plus less parts to break.
3/12/2016 10:39:39 PM EDT
[#35]
I have the LMT 10.5" upper. I love it and have no problems with it at all. I got the upper from BCM and it doesn't come with a BCG or charging handle. So I bought a full auto BCG and a BCM Mod 4 charging handle. To easy and no worries.

3/12/2016 11:25:15 PM EDT
[#36]

Quote History
Quoted:


Just curious, anyone who has the Mk18, and thinks its overgassed. Have you tried a Pri Gas buster, if so, does it make a difference.    
View Quote




 
Don't know if you'll be shooting yours suppressed or not.




Mines not suppressed and it's not over gassed.




As mentioned above, at least unsuppressed, it shoots as smoothly as all my other AR's.
3/14/2016 8:04:17 AM EDT
[#37]
I will be running the 18 Suppressed, More than likely all the time. I ended up buying a dedicated can for this weapon. In the beginning, I was buying a 30 cal can to cover a few other bases. When it came time to buy, I reverted back and bought another KAC QDC. That's what I am going to be running on my KAC Mod 1 CQB (Once everything gets out of jail). I am Looking forward to the MK18, I am not as worried about the blow back as I was before purchasing. I will run it, if something needs to change I will start then.

Thanks for all the post.
3/14/2016 5:34:56 PM EDT
[#38]
Make sure you buy an adjustable gas block. The < .080 gas port is pretty large for regular shooting, and definitely too large for suppressed shooting. However the interior diameter of the RIS II is very small, so some gas blocks like the Micro Moa Govnah will require minor filing to fit without contacting the inside of the rail.
3/14/2016 6:16:02 PM EDT
[#39]

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However the interior diameter of the RIS II is very small, so some gas blocks like the Micro Moa Govnah will require minor filing to fit without contacting the inside of the rail.
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Our 'modified' version was modified specifically for the RIS II and Geiselle rails and requires NO mods.





 
3/15/2016 5:34:59 PM EDT
[#40]
Thousands and thousands of rounds suppressed and unsuppressed out of my MK18, it is NOT over gassed and I don't care if the shells eject funny, it has never mattered lol.

As far as a suppressor fitting, I'm probably not much help because my can is discontinued but, IMO this is how a can should look with no barrel exposed between the two.

3/15/2016 8:03:12 PM EDT
[#41]

Quoted:


This has probably been asked. But I could not find the thread.



I am in the market for another sbr. I was pretty dead set on an LMT 10.5, but after a little reading I am starting to question my original decision. I am now looking at the DD Mk18.





I'm reaching out to any owners of this rifle to see if they are still pleased with their purchase. Any owners of the LMT are more than welcome to add as well.  The LMT is said to not have a full-auto bolt carrier. Which I don't like. Also it is not mil-spec (not to terribly important) and heavier that the DD.





Also the last request. Anyone running the DD suppressed, what can are your running? It says there are some that will not mount per the rail length. I have a kac can coming for my kac 11.5. But I will be buying another can to dedicate on this rig.





I appreciate any input.

View Quote
What do you not like about the FA bolt carrier?  FYI the DD has a M16/FA bolt carrier.
3/16/2016 8:54:15 AM EDT
[#42]

Quote History
Quoted:



What do you not like about the FA bolt carrier?  FYI the DD has a M16/FA bolt carrier.
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Quoted:



Quoted:

This has probably been asked. But I could not find the thread.



I am in the market for another sbr. I was pretty dead set on an LMT 10.5, but after a little reading I am starting to question my original decision. I am now looking at the DD Mk18.





I'm reaching out to any owners of this rifle to see if they are still pleased with their purchase. Any owners of the LMT are more than welcome to add as well.  The LMT is said to not have a full-auto bolt carrier. Which I don't like. Also it is not mil-spec (not to terribly important) and heavier that the DD.





Also the last request. Anyone running the DD suppressed, what can are your running? It says there are some that will not mount per the rail length. I have a kac can coming for my kac 11.5. But I will be buying another can to dedicate on this rig.





I appreciate any input.

What do you not like about the FA bolt carrier?  FYI the DD has a M16/FA bolt carrier.


I want a FA bolt carrier. LMT is said to NOT have a FA bolt carrier in there 10.5 rifles. Not that it matters now, I purchased the DD MK18 weeks ago.  



 
3/21/2016 9:36:00 AM EDT
[#43]
I have been using a DD MK 18 for the past 2 years and it has been very reliable.  It may technically be over gassed but it has been a great rifle for me.  I just recently acquired a Silencerco Omega and now I enjoy it even more.  Once you have had a chance to spend some time with the rifle, there are some good options out there to help regulate the gas.  As mentioned above, adjustable gas blocks are a popular option.  I have been testing Gemtech's new bolt carrier, which is supposed to help with the gas when running suppressed and have been happy with the results so far.

3/24/2016 6:04:10 AM EDT
[#44]
My Mk18 build is by far my most favorite rifle i've put together.  Its a Mk18 upper on a Spikes lower.  I run the Gemtech BCG and an H3 to fix the gas issue and it runs flawlessly suppressed and un-suppressed.  Sure the upper is heavy but its built like a tank and its the first rifle i'd grab if needed...  I've run it stock, with a Gemtech Trek, YHM LT, and currently i have an AAC Mini4 pending for this rifle.  The rifle has never failed to function in any configuration.  The Gemtech carrier and H3 buffer was purely to help soften the recoil pulse and slow down the action due to the larger commercial spec gas port DD puts in these uppers when shooting suppressed.  

Enjoy it! :)





In its current configuration with a TLR-1HL and AAC Brakeout in waiting for my Mini4 approval....

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