Reports of DD SBR barrels being over-gassed?

**Clint** · 07-16-13, 01:07

If the gas port is larger than you'd like, a BRT CustomTune Gas Port can correct it.

**Badger89** · 07-16-13, 01:38

Originally Posted by Noodles

I would be greatly looking forward to an adjustable block with a suppressed setting. I can't run the switchblock on my gun because of the NSR rail.

Can't is an awfully strong word...

http://m4carbine.net/showthread.php?t=128947

You don't even need to cut as big of a hole for the switchblock.

http://m4carbine.net/showthread.php?t=123287

Check out post #15. Good luck. Post pics when you're done!

**MistWolf** · 07-16-13, 04:14

Noodles, I think your getting wrapped around the axle. Over gassing does not generate more recoil. It can cause it to feel sharper, but the amount of free recoil remains the same.

You said Steve's rifle has a compensater. That makes a difference. So does ammo. Lighter bullets, less velocity, less powder make for less recoil. It could be Steve was getting rocked more with your carbine because he's not familiar with it. All in all, you don't have enough information to go on

**ASH556** · 07-16-13, 08:24

When I re-barreled this upper for KP I measured the gas port (12.5" barrel) and it was in the .07 range. Definitely not above .076. It's a DD barrel he purchased right when we built the upper. Either you've read misinformation or DD has changed their barrels to smaller gas ports than what you read.

https://www.m4carbine.net/showthread.php?t=127449

**BT6** · 07-16-13, 08:45

OP,

I'm not sure as to where some of these gas port diameters are coming from but a DD 12.5" should be about 0.073. It is hard to pinpoint specific issues without first hand inspection and shooting it ourselves. If you need anything from us, give us a call and let me know. If you would like to speak to me, ask for Mozak and you'll get to my desk. Thanks for your business. We appreciate it.

Matt @ DD

**markm** · 07-16-13, 08:45

Originally Posted by Clint

Have you measured the gas port?

What direction are cases ejecting?

This and This!

I had an 11.5 Sabre that gathered dust for years. I never realized that SBRs don't have to suck balls to shoot until I fixed it with an insertable gas port.

**ASH556** · 07-16-13, 09:22

Originally Posted by BT6

OP,

I'm not sure as to where some of these gas port diameters are coming from but a DD 12.5" should be about 0.073. It is hard to pinpoint specific issues without first hand inspection and shooting it ourselves. If you need anything from us, give us a call and let me know. If you would like to speak to me, ask for Mozak and you'll get to my desk. Thanks for your business. We appreciate it.

Matt @ DD

And that falls in line with what I measured right above this post.

**CoryCop25** · 07-16-13, 09:34

My M16 has a DD 12.5 barrel. I am almost certain that it is a .076 gas port.
I run an A5 -4 buffer with a GI rifle spring (Colt).
Although I run this suppressed 98% of the time, it runs 100% suppressed and unsuppressed. I generally use XM193 but it will eat Wolf also. I know it's a little on the heavy side with the VIS 2A but it is a pussy cat as far as recoil.