MK18 Vs. Geissele Super Duty 10.5

[elia.jon1]

Its kinda like what saw offers. Without the suppressor it'll start short stroking.

[okie]

Its kinda like what saw offers. Without the suppressor it'll start short stroking.

Which are you referring to?

[ta0117]

There's not much information out there. The Mk18 bolts were breaking at random intervals, so they started putting out feelers for a tougher bolt. That's when LMT came up with the enhanced bolt. Colt figured out how to toughen up the legacy bolt at the last minute, at no additional cost, so that was the obvious choice..

Pretty sure the issue with Mk18 and also M4A1 at the time was QC issue at Colt in early 2000s instead of a TDP change. Colt fixed the QC problem and the issues largely went away, rather than a change to TDP.

[elia.jon1]

Which are you referring to?

A 6921 cut to 10.3 without opening the gas port. I was asked if it would cycle when shot down near freezing.

It won't, specialized armament offers a similar barrel for suppressor use and says it won't work reliably without the can.

[Diz]

Well, to the OP, I'd say what is your mission requirement, and what do you think you'll need to accomplish it. That would largely determine what components I would chose for a "MK 18" style rifle. And by that I mean a SBR meant for CQB. Lots of issues have been covered in this thread. Especially concerning using Colt parts vs other vendors.

The only thing I'd add. While I agree with Okie, in that a cut-down 6920 would fit the bill nicely here, the issue for me is whether "TDP" type quality is even required. The argument was made that only Colt can truly claim to have this "mil-spec" quality, and has the track record to prove it. If we accept this as the case, then the question for me is do I really need this, or not. I found it amusing that while Okie argues for Colt, as the ultimate expression in things AR, he also states that the average AR-owner probably doesn't shoot more than a couple of hundred rounds through it. So you're saying here's the highest quality rifle available, but the vast majority have no need for it.

I think I'm somewhere in the middle of this here. I don't shoot 10K+ rds a year like some guys, but I shoot more than a couple of hundred for sure. So I want a certain level of quality, but I don't require a "battle-beast", whatever that may be. So to the OP, what is his firing schedule, and does he require TDP level of quality, or not? To me that is what would determine if you need Crane/NSW MK-18 parts, or big G, or whoever.

[indianalex01]

Pretty sure the issue with Mk18 and also M4A1 at the time was QC issue at Colt in early 2000s instead of a TDP change. Colt fixed the QC problem and the issues largely went away, rather than a change to TDP.

Where did you hear that it was QC issues at Colt with MK18 and M4A1?
How did they fix said QC issues with Mk18 and M4A1 and what where they?

[okie]

A 6921 cut to 10.3 without opening the gas port. I was asked if it would cycle when shot down near freezing.

It won't, specialized armament offers a similar barrel for suppressor use and says it won't work reliably without the can.

Gotcha. But it will cycle in cold weather with the suppressor, right?

[okie]

Where did you hear that it was QC issues at Colt with MK18 and M4A1?
How did they fix said QC issues with Mk18 and M4A1 and what where they?

Idk what he's talking about either. That wasn't the way I heard it at all. I wonder if he's confusing the extractor fiasco though, because that happened around the same time, and was due to QC issues. But it was a very small batch, and it did end up leading to the current extractor kit, which is pretty bad ass.

[indianalex01]

Idk what he's talking about either. That wasn't the way I heard it at all. I wonder if he's confusing the extractor fiasco though, because that happened around the same time, and was due to QC issues. But it was a very small batch, and it did end up leading to the current extractor kit, which is pretty bad ass.

He was just spewing nonsense. It’s never ending with Colt Haters. Just have to push on.

I have a colt Mk18 upper with stock gas port. It runs with federal 223 and 556.

[17K]

I thought the change that helped the carbines back then was the heavier buffers and the copper extractor spring and black insert?!