Modern Sporter builds Q&A
- Thread starter alberta tactical rifle
- Start date
Switch out the adjustable gas block to a mil-spec piece. Check the carbon ring around the port for proper alignment. What extension tube do you have, mil-spec or commercial? What bolt carrier are you running, Full Auto, semi Auto (full semi Auto) or colt modified?
I have rifle length gas. I also had trouble at first. Turned out my barrel port was undersized. I opened it up to 0.099" and it's working now.
For what it's worth, that's with 18.6" barrel, full mass Colt BCG and H1 buffer.
PinaKaleada
CGN Regular
- Location
- South of most
Anyone have info on 18.6” MIDLENGTH gas port size? Can’t seem to find any info on this.
- Location
- northern BC
Another thing to look at is the gas rings on your bolt make sure all your seams are NOT aligned.
That .99 is very large for a rifle length. What diameter and what is the OAL of the barrel?
18.6" barrel and 0.750" gas block.
I couldn't actually find solid info on gas port size for 18.6" barrels, but did see mentions of 0.098" for 20" barrels, even some random internet forum comments about up to 0.109".
Rifle works now with a non-adjustable gas block at the moment. I'm no expert, but it sure doesn't feel over gassed and was ejecting nicely at a 3 o'clock position during my test firing.
PinaKaleada
CGN Regular
- Location
- South of most
That .99 is very large for a rifle length. What diameter and what is the OAL of the barrel?
I’ve alao seen these charts and they often never have info on what a MIDLENGTH 18.6” should be. I asked RWA about IBI and their answer was 0.092”, but I think the journal is larger than 0.750”, so a 0.750” would be smaller. Anyone else have info?
I was the one that originally posted about having issues. I had the gas block set properly, and did try different settings to rule it out. I took the block off last night, and found that the gas port hole was not drilled all the way through properly. It is a barrel from a very reputable manufacturer, so I will see how they handle it. I spent many hours and gas driving back and forth to the range that I have access to, so I am not very happy about this at all.
Good news that it is working now. Personally I do not get hung up on the ejection location pie graph, but 2 to 4 seems what people strive for. Please remember that this changes as the spent brass strikes the receiver.
SuperDeadlyAccountant
Regular
- Location
- Niagara Region, ON
It looks like the anti-rotation tabs are quite large so I want to say it won't fit without modification.
I know this is a controversial subject, but I was wondering how you guys plan to break-in your barrels? I’ve been watching countless YouTube videos on the subject (I’m a new shooter). What do you guys do?
I have ATRS building my rifle for me. I’d like their take on this as well (as they test fire the rifle before boxing it up)... do you clean the barrel before running the first test bullet down the barrel? I’d love to hear your input on proper break-in procedures - as precision rifle builders.
I have ATRS building my rifle for me. I’d like their take on this as well (as they test fire the rifle before boxing it up)... do you clean the barrel before running the first test bullet down the barrel? I’d love to hear your input on proper break-in procedures - as precision rifle builders.
It's a touchy subject. I say it's a myth made up by barrel and ammo makers just to get you to spend more money to "break-in" a barrel. I never have and never will. I run 2-3 patches down the barrel before shooting it. Shoot it until it doesnt shoot anymore then clean it and shoot it again until it doesnt shoot anymore. So on an so on. There is no documented evidence supporting or denying with absolute proof that it does any good or any harm. It's all personal preference
No doubt about it. I'm super curious what ATRS take is on the subject. It makes perfect sense to me that it's important to clean the barrel properly to remove any debris, burrs, and gunk from the barrel before the first round is fired. From there... I have no idea? I want to make sure ATRS does clean the barrel of my rifle before the first shot is fired - which I'm sure they do!!
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No barrel leaves any factory without being test fired, so you're never really getting an "unfired barrel".No doubt about it. I'm super curious what ATRS take is on the subject. It makes perfect sense to me that it's important to clean the barrel properly to remove any debris, burrs, and gunk from the barrel before the first round is fired. From there... I have no idea? I want to make sure ATRS does clean the barrel of my rifle before the first shot is fired - which I'm sure they do!!
