View Full Version : DD 16'' carbine gas port .055, options?
The real issue is this is my SHTF/zombie/hippie rifle, and I would really like it to run everything. I had it malf (short stroking) on ALL 223 loads, but running xm193 like a champ. So my ? is, should reassemble and play with buffers/spring combo's (currently running T2 with some-odd spring) in hopes of finding setup that will run it all. Or while I got her stripped down, tool up and widen'er to mil-spec .0625? Have searched threads with gas port diameter/measuring port/etc. in title and got some good info, as this subject has popped up before. But no one really addressed the questions I'm after (if missed thread then please post) with intended use as far as versatility of ammo and reliability afterwards. Any help or opinions are always graciously accepted.
Get rid of the st t2 and get a springco spring before opening up your gas port.
Tzintzuntzan
06-12-13, 23:32
When did DD start making off size carbine gas ports? Last time I about heard gas port issues it was with the mid length barrels.
Get rid of the st t2 and get a springco spring before opening up your gas port.Ya was thinking about it.. Are saying from experience with this issue or do you just not like T2?
Tzintzuntzan
06-12-13, 23:51
I think it's just the fact that it sounds like you've got a too stiff spring and too heavy buffer combination for your rifle to cycle.
When did DD start making off size carbine gas ports? Last time I about heard gas port issues it was with the mid length barrels.I think this is an old barrel, there was some issues apparently a couple years ago http://www.midwayusa.com/product/461614/daniel-defense-barrel-ar-15-556x45mm-nato-m4-contour-carbine-gas-port-1-in-7-twist-16-cut-rifled-chrome-lined-chrome-moly-matte-with-low-profile-gas-block Some of the reviews make mention of it. I think guy I bought it from was sitttin on barrel for build, then decided to sell in parts craze.
I think it's just the fact that it sounds like you've got a too stiff spring and too heavy buffer combination for your rifle to cycle.Ya prob would be safe bet. I just don't look forward to trial and error with buffers at the expense of my wallet, when I can drill out for free. Not to mention there is no way to know if will even fix prob.
Tzintzuntzan
06-13-13, 00:11
I think this is an old barrel, there was some issues apparently a couple years ago http://www.midwayusa.com/product/461614/daniel-defense-barrel-ar-15-556x45mm-nato-m4-contour-carbine-gas-port-1-in-7-twist-16-cut-rifled-chrome-lined-chrome-moly-matte-with-low-profile-gas-block Some of the reviews make mention of it. I think guy I bought it from was sitttin on barrel for build, then decided to sell in parts craze.
Have you tried seeing if DD can't get you a new barrel?
Have you tried seeing if DD can't get you a new barrel?Aint to worried about it, I really don't mind doin the work. Hell I'm just glad to have figured out problem, good thing I'm a better machinist than gunsmith:happy:..
Tzintzuntzan
06-13-13, 00:32
I think I'd be a bit more cautious about "simply" making a bigger hole in your barrel. My preference would be to try a different buffer/spring set up first, and I'd guess you feel the same.
The correct size for a carbine port is .0625-.063. I would send it to someone competent to open it to the correct size.
ClearedHot
06-13-13, 01:24
I find it odd that DD uses seemingly random sizes for gas ports that no one else uses. I would think .055 would be undergassed unless you are running suppressed full time.
In another thread someone measured the gas port on a DD Mk18 URG and it was .082, which is overgassed. Colt Mk18 and LMT Mk18 uppers are .070.
It's usually said to be .058, LMT the same, and they run 5.56 like a dream. Wish I could get them like that still, in 14.5.
Tzintzuntzan
06-13-13, 02:04
Hardly under gassed, I've seen it run a lot of brass .223 and 5.56. Heck it even does okay with that steel garbage.
You could try put a regular carbine or springco carbine spring. Combine it with a real carbine or H1 buffer.
Opening the gas port up with more than likely fix it though.
If you open it up you are still running a shit buffer and an unknown spring. Why not replace those with a known quantity and then decide if you need to drill it out.
If you open it up you are still running a shit buffer and an unknown spring. Why not replace those with a known quantity and then decide if you need to drill it out.Was planning on upgrading buffer/spring regardless. In my defence it was it was on sale, got it a some years back before I knew about spikes and their T2(please do not revoke my m4c pass)... Think I'm just going to open up port while I've got the gun apart. Would hate to be right back at same spot, when I already know at least what 1 problem is.
Can someone give me a rational reason for debating this to death when we know what the proper port size should be?
Can someone give me a rational reason for debating this to death when we know what the proper port size should be?
Because people like to overthink this stuff then start jacking around with all sorts of buffer/spring combinations then wonder why their rifle doesn't work right.
.0625 is spec for a 14.5" barrel.
The 16" should need a little less.
I would drill is out to .0595" and call it good.
Get an H buffer and a mil spec spring.
Alternatively, the A5 system is a good solution that should help you run a wide range of ammo power.
I am fairly certain that Colt M4's and 6920's have the same port size.
.0625 is spec for a 14.5" barrel.
The 16" should need a little less.
I would drill is out to .0595" and call it good.
Get an H buffer and a mil spec spring.
Alternatively, the A5 system is a good solution that should help you run a wide range of ammo power.
They do, though he is right that a smaller port could be used.
I'm fine with my rifles not running .223.
BufordTJustice
06-14-13, 02:57
Ya was thinking about it.. Are saying from experience with this issue or do you just not like T2?
I'll reiterate from experience.
Springco WHITE and an H buffer.
sinlessorrow
06-14-13, 11:55
I am fairly certain that Colt M4's and 6920's have the same port size.
Doesnt Canada and SAS use a 16" M4 pretty much? Doesn't seem to affect to much.
justin_247
06-19-13, 16:19
Ya was thinking about it.. Are saying from experience with this issue or do you just not like T2?
Two things:
(1) The ST-T2 was designed for Spike's rifles that are tuned for that specific buffer... not yours.
(2) That buffer is way too heavy for the size of the gas port you're running. Try a regular spring and Carbine buffer.
The correct size for a carbine port is .0625-.063. I would send it to someone competent to open it to the correct size.
+1
Send it back to DD and they'll get it fixed for you.
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