DD Midlength 16” Undergassed?

**SouthwestAviator** · 02-25-19, 10:12

From the little info on this I’m able to find, it appears that Daniel Defense midlength gov’t profile 16” guns use a .072” gas port diameter. Can anyone confirm this? I assume DD doesn’t disclose that information like most manufacturers.

If it is .072”, doesn’t that seem a bit small? BCM uses .076” for the same setup. Would the DD 16” midlength have less reliability especially with weaker ammo?

**TexHill** · 02-25-19, 10:49

Originally Posted by SouthwestAviator

From the little info on this I’m able to find, it appears that Daniel Defense midlength gov’t profile 16” guns use a .072” gas port diameter. Can anyone confirm this? I assume DD doesn’t disclose that information like most manufacturers.

If it is .072”, doesn’t that seem a bit small? BCM uses .076” for the same setup. Would the DD 16” midlength have less reliability especially with weaker ammo?

I have a Daniel Defense M4v7LW that has a mid-length pencil barrel, and it has eaten everything I have fed it.

**RVTMaverick** · 02-25-19, 10:55

According to BRT's web-site: it is but not by much, looks like they're showing the same as BCM, a .076", I guess it could depend upon what they're (DD) is using for Buffer and Buffer Spring, BCG?

Originally Posted by SouthwestAviator

From the little info on this I’m able to find, it appears that Daniel Defense midlength gov’t profile 16” guns use a .072” gas port diameter. Can anyone confirm this? I assume DD doesn’t disclose that information like most manufacturers.

If it is .072”, doesn’t that seem a bit small? BCM uses .076” for the same setup. Would the DD 16” midlength have less reliability especially with weaker ammo?

**Headache** · 02-25-19, 11:05

I have been running a DDM4v5 as my "go-to" since 2012 time frame. It had a 16 inch mid-length barrel on it until I switched it out with a 14.5 mid-length about three years ago. I have primarily run Federal ammunition since swapping barrels, however, I ran a multitude of different ammunition brands and power through the 16 inch. I have had no issue what so ever with either barrel.

**SouthwestAviator** · 02-25-19, 11:16

Originally Posted by RVTMaverick

According to BRT's web-site: it is but not by much, looks like they're showing the same as BCM, a .076", I guess it could depend upon what they're (DD) is using for Buffer and Buffer Spring, BCG?

Afaik the DDM4V5 (the one I’m looking to get) uses a GI buffer spring and H buffer. Probably identical to what BCM uses.

It sounds like with good ammo in optimal conditions the undergassing isn’t an issue, but I wonder if it’ll start to hiccup in harsh/cold conditions and low power ammo.

Those of you with midlength 16” gov’t profile DD’s, specifically the M4V5, how many trouble free rounds do you have through it and what kind of ammo do you use?

I might go with a carbine length 14.5” but am considering the mid.

**MQ105** · 02-25-19, 11:43

My DD 16" mid runs Wolf Gold and various 5.56 at temps down to -5F. A5H2 and Tubbs AR10 spring. Standard M4 BCG, A2 FH. 4-5K rounds over the years and no problems.

**SouthwestAviator** · 02-25-19, 11:50

Originally Posted by MQ105

My DD 16" mid runs Wolf Gold and various 5.56 at temps down to -5F. A5H2 and Tubbs AR10 spring. Standard M4 BCG, A2 FH. 4-5K rounds over the years and no problems.

When did you get your’s? It sounds like they may have shrunken the gas port since 2017 or so.

**MQ105** · 02-25-19, 12:11

2015-ish... I measured mine at about .072. I used drill bits, and a 1.8mm (.0709") fit, but a #49 (.073") would not.

As additional info, my DD barrels are quite accurate. MOA 10-shot groups with the right ammo. They shoot 75 Gold Dots and 77 SMKs particularly well. 64 Gold Dot doesn't group nearly as good. I cut down a 14.5 to about 10.75 several years ago and it continues to impress, with north of 10k rounds through it, mostly suppressed.

Here is the 16". Bi-pod, rear bag and 2.5-10x NF.