6.5G MLGS 18" 0.089" gas port- Buffer System?

6.5G

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Minuteman
Apr 17, 2020
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For an 18" 6.5 Grendel upper with a mid-length gas system and supposed 0.089' gas port, what buffer system? Carbine with standard weight? Carbine with H, H1, H2? Rifle with standard weight?

I have seen many different opinions, sometimes from the same posters, here and on other forums.

I've heard free recoil is free recoil because physics; a buffer system does not reduce recoil but might slow the impulse. However I have heard rifle buffer systems slow the impulse.

I've heard 0.089 is a big port size for a 6.5G MLGS.

I've heard the main advantage of heavier buffers was carrier bounce in full-auto and tuning recoil with the buffer system is silly, and to use an adjustable gas block (AGB).

But I have also heard that an AGB is susceptible to carbon lock, and an adjustable bolt carrier or gas key is less susceptible.

I don't have enough experience to infer what is best from the information out there, because so few people have a gas port of my diameter. But I am stuck with this upper. What would you do to ensure reliability and secondarily reduce unnecessary recoil if it was your upper?

Thank you!
 
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I have a strong preference for fixed stocks anyway, so I would go with a Tubbs Flatwire spring & a standard weight rifle buffer/rifle receiver extension.

What upper/barrel is that? Gassed that uh...generously makes me think it's a BCA, but that's only a guess.
 
JS8588. Yep, BCA. I know it's bad haha. How bad is it/what am I in for based on your experience? This is why I'm asking about all the ways to address overgassing. What would you do?

What are the pros and cons to fixed stocks?

Thanks!
 
JS8588. Yep, BCA. I know it's bad haha. How bad is it/what am I in for based on your experience? This is why I'm asking about all the ways to address overgassing. What would you do?

What are the pros and cons to fixed stocks?

Thanks!

I've never owned a BCA barrel, but from those I know who have had them, it's like playing the lottery. You might have a shooter, you might have a tomato stake.

I've heard as many positive results with 6.5 Grendel BCA barrels as I have Faxon. Take that for what it's worth.

I wouldn't waste the money to put an an adjustable gas system on it, be it a gas block or adjustable carrier.

I'd put a good trigger in the lower (LaRue MBT 2S would be my choice). Grab a White Oak Armament Rifle Buffer Tube (they're like $20 and made out of 7075 T6 Aluminum. In other words, Mil Spec), a Tubbs Flatwire Buffer Spring, a decent standard rifle buffer (feel free to buy that from WOA while you're over there), and whatever rifle length stock floats your boat. I'd go with something heavy enough to balance out the barrel. RRA Operator fixed stocks are nice, but pricey, a Magpul MOE Rifle (not carbine) stock would work, or just go with a good old fashioned A1 or A2 stock.

Then assemble the thing, take it to the range, figure out whether or not you won the accurate BCA Barrel lottery, & go from there. If you did, mazel tov! If not, pull it & replace it with something better when $ allows.