With the DD MK18 10.3" upper I had at a .082 gas port causing nothing but headaches until I put Adj. Gas block on it. I figured that was the large side of the gas ports on the market. Until I received my 12 inch Carbine gas Larue Stealth Barrel yesterday. With a .092 gas port!!! I have come to the conclusion that this SBR will not even be attempted to be shot without an Adj. Gas block. Let alone suppressed as I had intended. This is my first go at a Larue barrel as I wanted to see first hand what kind of groups I could get from this thing. Plan was to scope it, run a surefire Socom can, and go blast away. $200 for the barrel seamed to be a deal, as I have 450 in my Noveske, figured why not give it a go. I opened the box, pulled the barrel out, first thoughts were… Nice barrel… Taper profile… Looked at the gas post and first thoughts were… OH NO! If you look at enough barrels, you can just tell right off the bat something was wrong. Maybe this should have been a 12" mid length gas with a .092
Can anyone really think of a reason to have this large of a gas port? If it was even the .082 like my MK18, with 2 more inches of dwell time, it would still be grossly over-gassed. I can do all the remedies to tame it down, with A5 and E-carrier, etc. But at .092… COME ON MAN!!
Looks like I wont be shooting this thing this weekend, and a SLR gas block hit the short list.
Wow. I’d guess that 75 percent of LaRue’s customers are imbeciles from AR15.com and he has to cater to the shit ammo, those dirt shooters are going to run in their guns. But .092 is excessive.
Have you called them to see if that port size was intended?? Not a LaRue apologist, but they could have simply screwed up your barrel. It’s worth a call.
There seems to lots of variation in GP sizes from different Mfgs, and that’s putting it nicely.
One possible explanation may be the use of light buffers and non-optimal gas system configurations.
If the action is on the verge of opening too early due to gas length and light buffer, adding more gas drive just tries to open the action earlier, while the chamber pressure is increasingly higher.
The higher gas drive is fighting an increasingly stickier cartridge, so there seems to be a range of bigger GP sizes that all appear to “work” the same.
That said, 12.5" carbines run very nicely unsuppressed with our .070" port.
Yes a phone call is in order. That’s on the Monday list. I wonder if the port size is “Top secret” like some others… Noveske for example. I agree the .070 would be a good size. But anything above that is large in my opinion on this barrel. Maybe I’ll get some more Dillo dust out of the deal.
Already got another SLR on order today. Running suppressed I’ll be wanting the Adj GB anyway. I was just taken back by the size. Hope it likes the 77gr rounds and groups as well as my Noveske.
That is gargantuan! Noveske also makes heavily gassed barrels but not that bad! I think BCM is one of the few to use ports of more appropriate size with the balls to say, " use good ammo!"
I am in the same boat will a new stealth barrel that just arrived, what’s the proper way to measure the port? I am actually having an issue with a Faxon 10.5" 300 BO barrel that seems to be under gassed at .075 per the specs but want to measure it.
Thanks Steve L. I just measured it with the “cheap” way with a drill bit and a 3/32 fit almost perfect and putting a mic on it I was at .092 as well. Not what I wanted to see.
All I can say is dang it. I was hoping I received a lemon.
Yes pin gauges are the way to go. Kinda pricey though… Until I bought a pin gauge set, I used to use a my snap on drill bit set. There were 60 something bits and I could get very close with the back side of a drill bit. That will at least gives you a general idea. If enough people come out with this same issue, well just call up SLR or Syrac and get a Adj gas block group buy going…
“Holy astringent plum like fruit Batman !” That shit is crazy, I had to get closer to my monitor to double check to see if I read that correctly. .092? What kind of hellfire is LaRue up to? Do they even shoot bro? Well let’s just hope that you two gents are the abnormality and that these two barrels accidentally passed QA, high hopes? After you shoot with the SLR I would be interested which setting you used.
I also bought a 12" Stealth barrel from LaRue during the recent sale. I called before I placed my order (Despite the confusion and chaos that must have been erupting there during the sale) and one of their tech’s was able to confirm the .092 gas port size with me.
I installed a Seekins adjustable gas block I had laying around and dialed it almost all the way closed. No issues locking back with an H3 running PMC Bronze. Since this is the lowest power ammo this barrel will see, that was my baseline.
Even when switching to a standard M193 over-gassing to the face was much less pronounced than my MK18. I’ve found my Gemtech Trek to be a bit better from a back pressure standpoint vs. my 556 SD.
I’ve contemplated trying a port insert in the .060ish range from Black River Tactical. This gun will run 100% suppressed and I feel it’s a more reliable option as I can’t get to the adjustment screws on the seeking with the rail installed anyway.
I originally figured this might have been engineered around a PST type adjustable gas block from the get-go, but somebody might have made a boo-boo on the spec sheet and they whipped up a whole batch of goofy barrels - and just sold them off at cost. Apparently catering to low-information shooters is a better concern financially to deal with.
I assume 99 percent of folks don’t know or care what the gas port size is… As long as it works…right :fie:
An Adj GB fixes the problem, and it will end up being a soft shooter like the other SBRs I have set up with them. but TehLlama might be on to something about the spec being off and then just sell em off… Didn’t think of that…
12" carbine gas is the same length dwell time as mid length gas 14.5" right? The gas port of a Noveske 14.5" mid skinny barrel I measured was about .088" BCM’s 14.5" mid ELW was about .078"
