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Posted: 4/2/2021 11:06:03 PM EDT
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That seems rather large. .093” is documented here: https://aimsurplus.com/faxon-firearms-16-in-gunner-223-5-56-4150-qpq-nitride-barrel/ Anyone have a Faxon gunner? What has been your experience? Is it overgassed? Or is it good-to-go? |
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I wonder where AIM got that size from ? ( and yes that sounds way to large for me ) The Faxon webpage makes no printed mention of the gas port size. https://faxonfirearms.com/faxon-16-gunner-profile-ar15-barrel-5-56-nato-pinned-gas-block/ |
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Quoted: .093 is huge for a 16” mid length, DD’s 16 mid has .0735. I measured a few i have. Colt 16” mid .071 DD 14.5 mid .076 Hodge Defense 14.5 mid .074 Noveski 14.5 mid .080 over gassed installed a BRT .074 gas tube Wow. The BRT gas tube looks like a good option / elegant solution. Something to consider. |
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Quoted: Expecting the customer to buy an adjustable gas block is no excuse for a grossly large port. It’s almost .020 larger than it ought to be. Some shooters probably think it’s under gassed with this barrel. Restricting the block is a lot easier than opening the gas port for most end users. Faxon barrels are probably my favorite so maybe I’m biased but I refuse to think poorly of them. 
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Quoted: Some shooters probably think it’s under gassed with this barrel. Restricting the block is a lot easier than opening the gas port for most end users. Faxon barrels are probably my favorite so maybe I’m biased but I refuse to think poorly of them. Take your blinders off. .093 for 16 mid isn’t right for any ammunition, period. Nothing. |
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Quoted: Take your blinders off. .093 for 16 mid isn’t right for any ammunition, period. Nothing. There must be a reason for it. Buyer spec? Piston upper? I’ve seen uppers with the fsb so crooked they likely had the gas choked off. More plausible is fore/aft mismatch. I’m not saying it’s necessarily “right” but it could make up for stacked tolerances. |
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This barrel is .625" diameter at the gas journal, right? I don't claim to know the science behind it, but I've overheard some pretty smart people talking about gas port volume vs gas port diameter (area). The gas block is .0625" (1/16") closer to the bore on a .625" journal than on a .750" journal. I don't know if that causes it to require a larger port but maybe that has something to do with it? |
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Quoted: There must be a reason for it. Buyer spec? Piston upper? I’ve seen uppers with the fsb so crooked they likely had the gas choked off. More plausible is fore/aft mismatch. I’m not saying it’s necessarily “right” but it could make up for stacked tolerances. What stacked tolerances are involved with a gas port? Incorrectly installed components do not constitute tolerance stacking. Faxxon barrels are grossly overgassed to compensate for low-education buyers that run crap ammo. I would never buy any of their products. |
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Quoted: This barrel is .625" diameter at the gas journal, right? I don't claim to know the science behind it, but I've overheard some pretty smart people talking about gas port volume vs gas port diameter (area). The gas block is .0625" (1/16") closer to the bore on a .625" journal than on a .750" journal. I don't know if that causes it to require a larger port but maybe that has something to do with it? Where a distinction is made it’s about .004” and the port for the thicker barrel is larger. |
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Quoted: There must be a reason for it. Buyer spec? Piston upper? I’ve seen uppers with the fsb so crooked they likely had the gas choked off. More plausible is fore/aft mismatch. I’m not saying it’s necessarily “right” but it could make up for stacked tolerances. Most likely the reason is that they has the right size reader in order but the barrels had to go out before they arrived. |
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Quoted: This barrel is .625" diameter at the gas journal, right? I don't claim to know the science behind it, but I've overheard some pretty smart people talking about gas port volume vs gas port diameter (area). The gas block is .0625" (1/16") closer to the bore on a .625" journal than on a .750" journal. I don't know if that causes it to require a larger port but maybe that has something to do with it? If a larger journal is more restrictive, as the gasses have more distance to travel before it hits the gas tube, logic would dictate that gas ports would be slightly larger for .750" journals. The distance travelled is also compensated on the gas block as the heights of gas tubes are the same between journals. I suppose that pressure would drop a bit more on a .625" journal as the gas travels between the barrel gas port to the larger gas block hole, but it would be a pretty negligible drop. Bottom line, there is no excuse for a .09+ gas port. |
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Quoted: What stacked tolerances are involved with a gas port? Incorrectly installed components do not constitute tolerance stacking. Faxxon barrels are grossly overgassed to compensate for low-education buyers that run crap ammo. I would never buy any of their products. My sub-moa AR10 has a Faxon barrel. When building it I bought a jig to dimple the barrel that referenced off the gas port. Using the dimple clocked the block a few degrees off center. I don’t have the tools or inclination to find out which parts are out of spec but the rifle runs great. Watching School of the American Rifle on you tube has made me doubt parts from all manufacturers. As long as the parts work together it’s fine for me. |
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That’s unusually large. When I bought mine, the website had the port sizes listed and it was 0.081”. Here’s a spreadsheet with a bunch of different barrels and their respective port sizes that seems to confirm their 14.5” barrels are 0.081. They used to be 0.078 when they first started making barrels, but probably caved to the people using shitty .223 steel cased ammo with an H3 buffer so people couldn’t say their barrels were unreliable. I’ve used Faxon barrels in maybe 3 or 4 builds and they work great u suppressed, but definitely need an adjustable gas block with a suppressor. |
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Definitely not all inclusive, but check this out for comparison... GP DIAMETER REPORTING |
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