Importance of an adjustable gas block in a 308 build?

[grizzman]

My old carbine buffer is a bit lighter than the Aero one. My guess is that this buffer with a standard 308 spring will fully eject the last round (naturally, the magazine follower is slowing the carrier in this situation) with Hirt and MEN.

This is only temporary, since I will be running an A5 system soon, with increased buffer options.

[RobertTheTexan]

Thank you to all who chimed in with their opinion. I appreciate the help.

I guess I didn't mention that also have the A5 with Orange Sprinco and KAK Heavy Buffer.
It's a good set up. Feeds, ejects, locks back just fine as I have fired it. (Non suppressed)

I've decided that I will go with the adjustable gas block., especially since I'm going to suppress it, at some point permanently although as said initially it will be a shared can. I think that's a good proactive approach to take considering the alternatives.

Rainier told me they almost exclusively use Superlative Arms adjustable GB's but I've read that while using the bleed off system (the thing that separates it from SLR Sentry adjustable GB) that there is a loss of velocity. I'm not 100% sure on just how much, but my SLR adjustable GB's are working just fine, so it's likely I will stick with them.
If it ain't broke......

Thanks again everyone who threw in their thoughts.


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[Clint]

I'll add that while the gas port size is the most important factor, the gas system length is a close second.

In the case of the 308 pressure curve, most barrels come with a system that is too short.

This situation is similar to a 16" carbine in 5.56 and leads to the ammo sensitivity and many of the problems that show up.

For 308, 16" and 18" rifles can work well.

[terraMODA]

An adjustable gas block is a must have with any platform/caliber. With the wide range of gas ports (in and out of spec) and ammo it just makes sense.
There's only so much you can adjust with springs and weights - if you have a wildly over gassed barrel that's the only way to tame it.
Why anyone would refuse the ability to adjust the one factor that controls the function of the gun - at a mere extra $50 or so is beyond me.

Because an adjustable gas block can render a semi auto inoperable if it's closed all the way or improperly adjusted, whereas a non adjustable gb can not.

[BufordTJustice]

Because an adjustable gas block can render a semi auto inoperable if it's closed all the way or improperly adjusted, whereas a non adjustable gb can not.

Not to sound disrespectful, but my retort would be, “SO DON’T DO THAT.”

One can shift a manual transmission wrong, causing instant, catastrophic damage. So it’s incumbent upon the user to educate themselves about what they are doing. I’ve not yet had a quality AGB fail when properly installed and not constantly toggled between settings.

The risk/reward is massively in favor of the reward for an informed user.


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