AR15.Com Archives
 Adco SCAR barrel cut down?????
FloridaCreekIndian  [Team Member]
11/25/2010 8:45:42 AM
Adco is my go to gunsmith for any and all barrel work so once I get my SCAR 16s I will be getting them to chop it to 14.5" and install the AAC 51 tooth SPR/M4 mount. Adco has said they have not adjusted any gas ports on the SCAR barrels they have cut down and have gotten no complaints about them not working. My question is: should I worry about any possible gas port issues with a cut down to 14.5" and if so, is there a nominal gas port size that has been found for a 14.5" SCAR barrel? Second is would it be better to have a slightly opened gas port rather than to leave it factory sized for a 16" barrel? I don't plan to buy a suppressor any time soon so lets just say I will be running this unsuppressed for a long time.

I trust Adco 100% but just because they have not adjusted the gas port doesn't mean "you guys" haven't tinkered with them after the fact
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JohnnyMcEldoo  [Team Member]
11/25/2010 3:31:57 PM

Originally Posted By FloridaCreekIndian:
My question is: should I worry about any possible gas port issues with a cut down to 14.5"


No
tctlrld  [Team Member]
11/25/2010 3:37:40 PM
Just going to 14.5" I wouldn't worry one bit.
scoutfsu99  [Team Member]
11/25/2010 3:49:28 PM
Mine would feed M855 but not any 55 grain after I cut it down to 14.5. It's being fixed right now
SRTM4  [Member]
11/25/2010 6:45:53 PM
It appears that many people are not having any issues with their 14.5 barrels. Most seem to be running fine.

For whatever reason my SCAR ( with 14.5'' bbl ) would not fire wolf or PMC ammo consistantly.

I had to open my gas port up to .063 up from .055. It has never missed a lick since then.

Pm me if you have any issues with yours. I may be able to help you out.
FloridaCreekIndian  [Team Member]
11/25/2010 6:52:24 PM
I am just trying to get a feel for all of this and see what people are experiencing. I wonder if I should go ahead and ask Adco to open the port to the spec you listed or just leave it alone and test fire etc.

I will probably leave it alone for the time being as they will take care of any issues after the fact.
SRTM4  [Member]
11/25/2010 6:57:20 PM
Originally Posted By FloridaCreekIndian:
I am just trying to get a feel for all of this and see what people are experiencing. I wonder if I should go ahead and ask Adco to open the port to the spec you listed or just leave it alone and test fire etc.

I will probably leave it alone for the time being as they will take care of any issues after the fact.


I would probably leave it alone at first. It may run fine. If you have any issues you can send it back to ADCO. Im sure that they would be happy to open the gas port up to whatever you tell them too.

Tactidork  [Member]
11/25/2010 7:45:10 PM
I've been considering this.. how much was it?
FloridaCreekIndian  [Team Member]
11/25/2010 9:04:36 PM
Cut , thread and re crown is the same as the AR barrel work but they charge $100 to perm. attach the AAC and Surefire muzle devices because they are so hard to deal with.
west996  [Team Member]
11/27/2010 3:39:52 PM
I'm probably going with ADCO for the 14.5" with perm AAC flash hider. I'm curious about functioning and opening up the gas plug also. I'd hate for it not to function with 55 grain, just because I have so much stockpiled. Wonder if there is any way to purchase the gas plug for the SCAR standard 14" barrel from FN.
FloridaCreekIndian  [Team Member]
11/27/2010 3:57:21 PM
If you find out let us know. I have also been following some threads on the FN forums in reference to barrel cut downs and gas port sizes. I generally use 55 grain stuff as well and that is what my department uses for duty ammo so it is imperative that my rifle function using it.
SRTM4  [Member]
11/27/2010 10:52:13 PM
Originally Posted By FloridaCreekIndian:
If you find out let us know. I have also been following some threads on the FN forums in reference to barrel cut downs and gas port sizes. I generally use 55 grain stuff as well and that is what my department uses for duty ammo so it is imperative that my rifle function using it.


If done right, the SCAR barrel cut down is not a big deal. Have ADCO or Marvin cut and crown it and you may be done (14.5 bbl ). If you do have to open up the gas port it is a matter of taking your time and tuning the rifle to fire weak ammo. Everything else should function without issue.

The gas port drills very easy. Some will argue that you need to ream the hole out to size. That is fine but I personally do not think that it is necessary when using good cobalt or carbide drill bits in # sizes.

Im sure that most guns will be slightly different but Im pretty certain for us semi auto guys the gas port sizes will be close.

So far we have found that the factory 16'' bbls are very close to .055 on the gas port.
14.5 bbls - for me .062 worked and I went another .001 to .063. Some may be a bit less and some a bit more.
10'' bbls - from the couple of guys that cut theirs it seems that .077 is the happy number.

Like I said these numbers may vary but should be close.
Colt_sporter  [Team Member]
11/30/2010 8:34:07 PM
Contact SR-47 (a member here) he is very familar with this operation. He chopped mine to 10.0". I strongly suggest you contact him.
FloridaCreekIndian  [Team Member]
11/30/2010 8:49:39 PM
Originally Posted By Colt_sporter:
Contact SR-47 (a member here) he is very familar with this operation. He chopped mine to 10.0". I strongly suggest you contact him.


Already did but don't want to be without my barrel for a month. Even he mentioned a possibility of having to adjust the gas port with a 14.5" barrel cutdown. Does anyone have confirmation from FN that cutting a barrel will void the warranty on the rifle? I could imagine it voiding the barrel warranty but what about the rifle in general?
FloridaCreekIndian  [Team Member]
12/2/2010 6:16:29 PM
I heard back from FN today. The told me cutting your barrel will void the warranty on the rifle. They also said they do not sell the gas orifics or barrels seperately. They recommended rhat I leave the SCAR at factory spec. for now. Being LEO and not made of money I think for now I am taking FNs advice
Friendly_Crusader  [Member]
12/2/2010 6:27:39 PM
Originally Posted By FloridaCreekIndian:
I heard back from FN today. The told me cutting your barrel will void the warranty on the rifle. They also said they do not sell the gas orifics or barrels seperately. They recommended rhat I leave the SCAR at factory spec. for now. Being LEO and not made of money I think for now I am taking FNs advice


being an LEO, do you think you could pull some strings and have your Dept. ,or a C3 dealer order you a complete barrel assembly?
Papi4baby  [Team Member]
12/2/2010 6:49:45 PM
Originally Posted By Friendly_Crusader:
Originally Posted By FloridaCreekIndian:
I heard back from FN today. The told me cutting your barrel will void the warranty on the rifle. They also said they do not sell the gas orifics or barrels seperately. They recommended rhat I leave the SCAR at factory spec. for now. Being LEO and not made of money I think for now I am taking FNs advice


being an LEO, do you think you could pull some strings and have your Dept. ,or a C3 dealer order you a complete barrel assembly?


This.

FN is making a 10" barrel, not sure if they are available.

Good luck.
FloridaCreekIndian  [Team Member]
12/2/2010 7:56:43 PM
Not looking to SBR this (have 2 SBR ARs) but would love to have a 14.5" barrel. One of our captain's is a C3 dealer also so I will have to call him and check.
JohnnyMcEldoo  [Team Member]
12/2/2010 9:55:25 PM
I cut mine to 14.5" and perm. attached the factory brake and have shot wolf and silver bear primarily with no noticeable difference in performance. Also, it would not be a big deal to make a new barrel port insert to test out. Any competent machine shop could make one for you.
FloridaCreekIndian  [Team Member]
12/2/2010 11:29:09 PM
i understand that Marvin and Adco can do the job with no issue. I just am not sure I am ready to risk losing a warranty on a $2200 rifle. Call me scared but that I am now

I am trying to weight the costs and not just monetary. Yes, the 14.5" SCAR barrel looks much better but it is just an aesthetic issue. The sub $200 cost is not a big deal at all but not sure if looks is worth not having the warranty offered by FN.

I saw on the FN forums where someone has designed a SCAR gas block and intends to sell them. Once someone starts making aftermarket barrels or barrel parts it wont be an issue. Maybe FN will eventually make those items in the US so it will be a non issue. I think I will hold off for now and see where this goes.
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