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Old June 12, 2024, 08:04 AM   #26
zukiphile
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Quote:
Originally Posted by MarkCO
Yes, but there is pressure and volume. If you make the gas port larger, and fill the tube the chamber pressure drops faster, but you push more gas into the BCG. It's a dance that most folks only see one way, but it can be used to mitigate pressure if you have a way to bleed of excess gas (like a Superlative Arms or a Gas Key bleed off).
Before your post above, I hadn't considered the variable of pressure as separate from volume, or the utility of the bleed off feature, for which I found no good use on my 20" rifle.

Am I thinking about this in reasonable terms if I imagine that a 16" carbine barrel using the bleed off feature, along with a lighter carrier and spring, could result in modest bolt speed despite the system being under pressure for the last nine inches or so of barrel?
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Old June 13, 2024, 08:11 AM   #27
MarkCO
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Join Date: October 21, 1998
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Originally Posted by zukiphile View Post
Before your post above, I hadn't considered the variable of pressure as separate from volume, or the utility of the bleed off feature, for which I found no good use on my 20" rifle.

Am I thinking about this in reasonable terms if I imagine that a 16" carbine barrel using the bleed off feature, along with a lighter carrier and spring, could result in modest bolt speed despite the system being under pressure for the last nine inches or so of barrel?
Yes. I must admit I am not a fan of gas key bleed off, but there are a few times where, given the barrel and ammo, it was the best solution to a good tune.

Magnetic and mono material high durometer buffers have shown some benefits in testing I have done over the last year, but gas volume and pressure are still the two biggies before the fine tune of the system.

And, FWIW, the Stretch16 was the original Intermediate gas length 16" AR barrel. The fact that a lot of folks have copied the configuration attests to it's benefits. But, yes, sometimes it's better, economically, to spend say $50 on parts as opposed to a whole new barrel.
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