Reports of DD SBR barrels being over-gassed?

[Noodles]

I'll tell you right now, don't waste your time with checking the actual port size. The actual bore diameter matters in relation to port size, so knowing one without the other is pointless.

For instance, my 12.5 DD has a .076 or so but it is DEFINITELY overgassed, but I'm almost certain that at least in my sample the bore on this CHF barrel is definitely tighter than others. I figured this out on my barrel by trying specific port sizes on multiple same length barrels (using a MicroMOA gas block), that is, my gun would run between .065 and .060 when others wouldn't. Robert at MicroMOA mentioned he had seen the same thing, that not all equal port sizes are 'equal'.

Don't chase port sizes. Get an adjustable block and dial it in for your cfg.

Edit: I will say that I have taken this 12.5" suppressed out to 600 and 700y on E sized targets with an aimpoint. My thought is the tight bore is definitely helping accuracy. If DD hadn't made the port so stupid huge, this would be an excellent barrel!

[Pappabear]

This whole thread speaks to buying quality firearms. All my guns run like a scalded dog. My new LMT didn't like LMT's enhanced carrier. Other than that, sticky to DD , LMT, NOVESKE, COLT AND BCM, the gun should run. I have never used an adjustable block, but Mark has with much success.

[Jwknutson17]

I'll tell you right now, don't waste your time with checking the actual port size. The actual bore diameter matters in relation to port size, so knowing one without the other is pointless.

For instance, my 12.5 DD has a .076 or so but it is DEFINITELY overgassed, but I'm almost certain that at least in my sample the bore on this CHF barrel is definitely tighter than others. I figured this out on my barrel by trying specific port sizes on multiple same length barrels (using a MicroMOA gas block), that is, my gun would run between .065 and .060 when others wouldn't. Robert at MicroMOA mentioned he had seen the same thing, that not all equal port sizes are 'equal'.

Don't chase port sizes. Get an adjustable block and dial it in for your cfg.

Edit: I will say that I have taken this 12.5" suppressed out to 600 and 700y on E sized targets with an aimpoint. My thought is the tight bore is definitely helping accuracy. If DD hadn't made the port so stupid huge, this would be an excellent barrel!

I understand what your saying. My MK18 is so overgassed its not even funny. As reports of the gas port being .08+ as others have stated in this thread. I was curious if they started opening up all gas ports on there barrels. I have plenty of BCM barreled guns that run perfect. With and without a can. I already have a SLR gas block on a 100% suppressed bcm 11.5. Works great. But what I dont want to do is buy one for every stinkin rifle I own. I have a opportunity to pick up a DD m4a1 for pretty much nothing, and just was curious if they opened the port up, considering they did that for the Mk18. Ill still pick it up either way, but Im just curious...

[Cincinnatus]

Nevermind. Read something wrong.

[wirides]

I understand what your saying. My MK18 is so overgassed its not even funny. As reports of the gas port being .08+ as others have stated in this thread. I was curious if they started opening up all gas ports on there barrels. I have plenty of BCM barreled guns that run perfect. With and without a can. I already have a SLR gas block on a 100% suppressed bcm 11.5. Works great. But what I dont want to do is buy one for every stinkin rifle I own. I have a opportunity to pick up a DD m4a1 for pretty much nothing, and just was curious if they opened the port up, considering they did that for the Mk18. Ill still pick it up either way, but Im just curious...

So how does that translate to the real world? That's what I haven't seen. People are quick to poo poo and scream "overgassed" and they well could be but how does that affect things? How is a the gun to shoot? How does it run?

[Jwknutson17]

So how does that translate to the real world? That's what I haven't seen. People are quick to poo poo and scream "overgassed" and they well could be but how does that affect things? How is a the gun to shoot? How does it run?

No screaming or poo poo here . I'm just curious what the spec is. If no one knows then I'll just wait for DD to get back with me. No worries.

But no matter what company the rifle is, DD, BCM, Colt, etc, all good companies, I would still like to know what the specs are and decide what's best for me, myself.

[wirides]

Right, but I'm asking specifically about the real world performance of your mk18?

[Jwknutson17]

Right, but I'm asking specifically about the real world performance of your mk18?

Its over gassed. No if's, and's or butts. It runs suppressed 100% of the time and only with 5.56 ammo. Tubbs flat wire and H3 buffer and still spits em out at 2 o'clock every time. Brass doesn't look so great. Its overgassed. Don't need to elaborate anymore on that. Think MarkM was having issues also but got them ironed out with a Syrac.

[wirides]

Thanks for the response. I guess all I'm getting at is that it would be beneficial for those considering the dd to know real world accounts of how the gun ACTUALLY runs. For example, while overgassed, how does it ACTUALLY run unsupressed with 223 ammo?

[Jwknutson17]

Thanks for the response. I guess all I'm getting at is that it would be beneficial for those considering the dd to know real world accounts of how the gun ACTUALLY runs. For example, while overgassed, how does it ACTUALLY run unsupressed with 223 ammo?

Im sure it would run just fine. The only time I shot with it, without a can, was with a H2 and BCM spring with 223 Fiochii. I ran less then 1 mag through it indoors and have yet to shoot it without a can since. Brass was at 3 oclock. I remember this becasue it bounced off the wall and landed back between the stock and my nose and burnt me. Other then that, someone else would need to chime in as Im not the one to talk from experience with 223 ammo and a non suppressed MK18 setup that your looking for..