So I built a block 1ish clone a while back and have an A2x pinned and welded on the socom 14.5 barrel. I wasn't too concern with having a pinned md because I didnt have any reason to change it.

Fast forward to now and I have a SiCo Omega in jail and will be getting asr mounts for my rifles. I am seriously debating sending the barrel to Adco to get chopped. Lower is already sbr'd (pinned to 16" to easily travel across state lines). I have another sbr with an 11.5 bbl but I've always loved the look of the 10.3/.5.

Now, I don't know if I want to do 10.3 or 10.5. I am leaning towards 10.3. I've read that people who do this open the gas port up to .070. Once I get the suppressor it will be ran suppressed 95% of the time. Should I open up the gas port? 

Anyone have a Mk18 mod 0 with an omega they could post a pic of? I want to make sure that with a 10.3 bbl I still have clearance with the bayonet lug.

Pic of said rifle. Thanks for any info.
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Anybody? I am probably going to with 10.3 assuming I have room for the omega. Should I open the gas port to .070?

I have not yet decided on a can BUT...

On my 10.5" LMT...



I have 5/16" (.3125") from the very front surface of the lug to the where the crush washer is.

Edit...

Corrected the measurement after putting on my glasses...  

Gas port size should be the same for either 10.3 or 10.5. The mil std is .070" (Colt barrels), but I've seen them opened up to .083"+/- (DD). Send it to a reputable company like adco and they will open it up for you when they do the chop to the proper size.

I have a factory Colt 10.3" barrel on what is now my former block 2 clone and it has the .070" gas port. Runs everything I put in it great, suppressed or not (do note that I haven't put wolf or similar steel cased offerings through it)

Thanks for the replies. Yea I plan on sending it to adco when I do decide to get it done. Sounds like 10.3 with .070 gas port will be the way I go. 

Yes, that port size is the norm.  I’ve had ADCO chop several barrels for me, one being a SOCOM.  It’s setup as a CQBR clone so it’s under a DD Mk18 rail.  I’ve run a different 10.3” barrel with FSB and an OMEGA using the ASR mount and it clears the bayo lug just fine.  Do it with confidence.

Sweet. I plan on sending it off early this week.

On another note, I'm thinking about getting the vltor a5 buffer kit. If I do, I'm going to get the re10 6 position tube and the a5h2 buffer. Anyone have experience with it?

Do not chop, get a short barrel in the length you want that is made by a reputable manufacturer
and the gas hole should be GTG.

It is actually a bit cheaper to sell your 14.5 and buy the correct size, plus your don't chop off the factory barrel markings.

Chop it. I have had ADCO cut a few 6920 barrels, the concentricity will be spot on, which is one less thing to worry about.

That's always worked for me.

Thanks for all the input. I've already paid for the chop and I'm shipping it to adco today. I'm not concerned with losing the markings. 

I don't see it being much cheaper to sell and buy a different barrel. To be honest it's not worth the hassle for me. I bought the barrel and fsp for $150 so after the cut I'll have $225 in it. Not bad if you ask me.

Just a little update. Got my barrel back from adco. They did an excellent job. Here's how she sits now. About to hit the range to re zero it.

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Very nice, I like the looks of that how it turned out.