Suppressed Mk18 malfunctions

[Jwknutson17]

These shorties will run an H2 and car spring with a GP of .064 with 5.56 ammo unsuppressed pretty easily. I no longer have my DD 10.3 because the GP measured at .082. An adjustable gas block of some sort is the only true way to fix the true cause. While you can try to patch work the rifle to run a little better, DD pretty much ruined a good barrel with that gas port size.

And the numerous times Ive spoke with DD about this issue is addressed as this.... We have much less complaints of overgassed 10.3s with .08x spec gas ports then we would with a .070. Way to many folks do not run 5.56 ammo all of the time and do not run suppressors. SO for a commercial MK18 upper, we have much less complaints having the gun running with all ammo types. This was the basic explanation I received back from a few separate emails into DD a while back.

I see why they do it, but to a select few people that run quality ammo, suppressors, etc, its a major pain. I would run an H3 at least. Or Vltor setup. But I found that it still didn't accomplish what I was after and sold the barrel. Just a lot of time and money...

[dentron]

I wonder if Clint has a port reducer that will work for this set up?

I recently inquired about the insertable ports and they informed me they were only selling them with the gas block as a kit. Bummer cause I want to keep using my factory pinned block.

[jpmuscle]

They really should just offer two separate 10.3 barrels to save everyone the headache

[Jwknutson17]

They really should just offer two separate 10.3 barrels to save everyone the headache

DING DING DING!! Now wouldn't that be nice!!! Buy barrel A if you shoot crap ammo. Buy barrel B if you only shoot 5.56 ammo or plan to suppress your rifle.

[Y8598]

Well even if you have a well machined gas port on your rifle and you're shooting crap ammo. As for mentioned a heavier buffer we will take care of that such as an h6. it will also help to guarantee a reducing factor of squib load or squib round. yes the buffer can help with that at least in an M4 / AR15 style rifle.

[TehLlama]

DING DING DING!! Now wouldn't that be nice!!! Buy barrel A if you shoot crap ammo. Buy barrel B if you only shoot 5.56 ammo or plan to suppress your rifle.

Yeah, just make a second SKU for a 0.071 gas port on the same barrel, call it 'suppressor ready', and then see which sells. I'm willing to bet anybody in the market for the Mk18S or Mk18HP barrel would be willing to wait through a backlog just to get a barrel for their intended use - to my knowledge the only other complete Mk18 uppers using CHF barrels are in another zip code of price, so that's an offering I'd consider to be overdue from DD.

FWIW, I'd be running a DD Mk18 upper if this was resolved, I really like my V5 upper because of how well it shoots. Instead, I'm running a different 10.5" barreled upper, because of this specific concern (as it's a dedicated suppressed upper).

[jpmuscle]

I'd even be willing to put together two separate mk18 uppers if they released a proper spec barrel.

[munch520]

You've lost me man. What do four last 4 posts have to do with the topic at hand?


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[jpmuscle]

Yea pretty sure were only discussing what we can actually buy lol. What's the difference between the mk18 .mil rail and the two mk18 fde rails I have sitting in front of me?

As for the barrel all were asking for is one with the right dam gas port lol

[BC98]

You've lost me man. What do four last 4 posts have to do with the topic at hand?


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I agree. The cost of a "true" MK18 rail or barrel is irrelevant to the problems that the OP is experiencing. I'd also like to know how drilling a different gas port diameter pushes the cost of the barrel to $1200. In the interest of not further derailing this thread, I'll live without an explanation though.

If the OP's gun is overgassed with .223 spec ammo then running 5.56 pressure ammo will only make the problem worse, regardless of the type of brass used. Brass/ammo cannot be purchased directly from LCAAP. Per the facility management contract, they are allowed to sell excess brass and/or ammunition if requests are made by another manufacture (i.e. Federal, Black Hills, etc.).

I believe the talk of out of spec on the gas port is in comparison to the Crane spec for the Mk18 barrels (which is pretty universally known) not with respect to the manufacturing spec of a civilian barrel. The fact still remains that .082" gas ports are excessive for anything except steel case import ammo. The barrels could be more conservatively ported and still function .223 pressure ammo without issues and would be more likely to run better when suppressed.