Gas metering.

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Demi-human

Demi-human

maybe likes firearms a little bit…
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I am assembling components for another rifle. A lighter weight one.

It has come to the gas system and I have options. An expensive, adjustable titanium gasblock, or, an even lighter non-adjustable block and an adjustable gas key.

I know how the gas blocks will work, but I have no experience with an adjustable gas key.

So all y’all out there in rifle country, have any of you any experience with an adjustable gas key?
Any detriments to it?
Do they even work?

Thank you kindly for you thoughts.:)
 
I will assume you are talking about a AR.

Adj. Gas keys work just fine.... However, I promptly dropped one of the set screws for mine... so if you are considering a set screw type, order spare screws.
I also question the "position" of the gas flow restriction on a adj. gas key... it seems to me, ( and while it still restricts the gas for operation ) you are still getting the full gas flow into the upper. A Adj. GB would restrict the flow at the gas block, only allowing the required gas into the upper.
Something to consider if you are going to suppress the upper.

Another way to consider, is a Black River Tactical custom gas tube. Life of those appears to be more than 5K rds, from their testing
https://blackrivertactical.com/WP/BRT-EZTUNE-Gas-Tube-Configurable-Midlength-p103167236
 
Personally, I don’t think, systemically, adjustable carriers or keys make as much sense as an AGB. By restricting pressure and flow at the block, we know only our desired operating flow/pressure reaches the action. By restricting at the key/carrier, we know only enough flow/pressure reaches our piston, BUT, we potentially have a vent (leak) into the action by an imperfect seal between the key and gas tube - the interface of which is then still receiving peak pressure as if the restriction did not exist. So much like gas “bleeding” gas blocks, I just don’t believe adjustable keys or carriers align with what I want in my operating system.
 
This new rifle may have a suppressor on it, @bfoosh006, so that would be a good consideration.

Varminterror said:
I just don’t believe adjustable keys or carriers align with what I want in my operating system.
Click to expand...
This is what I am thinking too. I suppose I just needed it said by someone else.
I don’t suppose there would be more gas than a regular rifle would have in it, wait, rethought, that operational gas leaves through the bolt port, the restricted gas would be inside. Yeah, not ideal.

It’s just the gas blocks I want are six months out. About the same as the Balios receiver, 25 weeks, so an Anderson slick side was purchased. I don’t think I want to sacrifice the ounces out at the end of the handguard though. It will shoulder sling better with a light front end

I like the Superlative quality, but also run my bleed off block in restricted mode. Why not have that gas go through the suppressor?
Upon further reflection, an adjustable key and a titanium block cost nearly the same as an adjustable gas block too.

I guess I’ll bite the horse and get a 2A adjustable titanium gas block. SLR makes nice ones too, for the price of my barrel!

Thank you for the brainstorming, gentlemen. It is appreciated. When I think alone things get out of hand quick.:)
 
I wish I knew. You need the engineering specs on how much pressure is required to function the action. The ammunition is critical as each generates different pressures. Barrel length also plays a role as the longer the barrel, the longer the time the pressure stays in the barrel. Ruger had a formula for gas port size and barrel lengths for the Mini-14. Unfortunately I've never learned what it is for the AR action.

Kudos to FN in their four position gas port on the FAL.
 
taliv said:
this is what i'm putting on my next build
www.riflespeed.com
Click to expand...

I actually saw one of these in the wild a few weeks ago, and drooled a little bit, then realized where I’d seen it before (your threads here) and drooled even more. I love the idea of the extended control “ring”, since I cover all of my GB’s - and end up drilling holes or relieving mlok or keymod holes slightly to allow access to side screws or buying more and more long Allen keys to reach front screws.

I still need a solution for nested suppressors that I like better than side screw AGB’s, but I REALLY like this rifle speed product!
 
taliv said:
What do you mean?
Click to expand...

gotboostvr said:
Cans that tuck under the handguards I'm assuming.
Click to expand...

Yup.

My current “go to” set of SBR uppers all have my suppressors sitting 1/2” to 1 1/2” back into the handguard. So the adjustment ring/collar on the riflespeed blocks couldn’t extend out of the handguard for access. Most of my Title 1 AR’s all could use rifle speeds - except maybe a couple middy’s with 15” handguards, since the collar would need to be, what, 7” long?
 
JP has a very nice adjustable gas block.

Beware: Gas blocks that are adjustable for 3gun shooting (to absolutely perfectly tune gas system to handloaded ammo for light recoil), are completely different than swing lever gas blocks for suppressors.

You index the lever gas block for suppressor operation, then swing it to the open position for non suppressed use. Some lack the ability to be set in the middle, or can be a pita to deal with.

It may, or may not, be as fine adjustable as the 3gun types. Some 3gun types are duel setscrews. Thread lock required from time to time. Some are a clickable valve. I believe the JP is a clickable valve. It's been a while.
 
@Zerodefect - not all of the JP blocks are clickable - aka, has adjustment detents. I think only one model offers detents, in fact. They’re still great blocks, I’ve preferentially used hundreds of them over the years, and all but one (or two?) of my personal AR’s currently sport JP adjustable blocks.
 
Those RifleSpeed gas blocks are neat. Very forward thinking. But even their shortest one is nearly twice the weight of even a steel SLR.

The Aero Precision is the same weight for a Benjamin less than the SLR.

A Rubber City key and 2A regular titanium gas block is less than half an ounce. But blows gas around the receiver.

Not that weight is the end all, but it is a major consideration. Short handguard, red dot, ten round mag, sling. That’s it. When a Balios receiver set come to stock I’ll be switching receivers.
The small parts I could get in titanium, are. The BCG is low mass and the spring is reduced power. I’m looking for trigger group weights, but will sacrifice mass here for a nice cartridge trigger if necessary. I have a 2 lb CMC already, but don’t know the weight.

I have either talked myself into finishing this rifle right, or not sweating an ounce, since I’ve saved it everywhere else, and saving some coin.

Perhaps I should flip a coin?
Heads, SLR titanium perfection.
Tails, Aero steel practicality.
 
The real selling feature of an adjustable key is: location location location. The RCA won’t work as well for its intended purpose but definitely eases accessibility.

I’m now stuck on JP adjustable blocks since VT recommended them. It’s one long Allen Key and provided in the box. As mine sees a steady diet, no need to adjust beyond the initial setting unless I opt to add a suppressor later. In your case…man I’d want to spend $200 for that riflespeed. Not saying I would, just dreaming big with your budget. Over 5,000 rounds that’s what, .04 a shot? Hey, do it. Do it.

Do it.
 
Unfortunately, it seems like none of the cool blocks come in .625” gas seat that rests on the Faxon pencil barrel I have. None of the Riflespeeds, no JPs, not the Strike collar adjust, which I happen to like. A small pick could manipulate that through the guard easily.

Since I’m not a go fast competitor, but I am a dad, I might defer to my wallet’s suggestion of Aero practicality. It’s only six tenths of an ounce heavier. I just want a very light rifle I can carry everywhere. Most of mine are not very practical. They are awesome, or accurate, or elderly. That is read “heavy as heck”.:)


This one will be svelte.
 
Varminterror said:
SLR Sentry 6. GTG.
Click to expand...
And they do address a specific issue that detent adjusters have, the spring losing temper. This rifle will not be shot enough to ruin a spring, but the SLR is titanium. I like titanium. The grey is nicer, and it just tastes better.
The price doesn’t. But I’m worth it.:D
(Really I just paid off my truck. I get a reward for diligence. Aforementioned rifle.:cool:) It may be a minute for pics…:oops:
 
Here it is installed.
image.jpg
Thanks RTB.com! I am weak, and you know it!

I just need a “thread protector”.;)
Maybe a titanium dust cover and pin. Plastic would be lighter.

I’m hoping for a nice ride from the lightweight carrier, reduced power spring and adjustable gas block.

I bought another reduced power spring thinking I’d lost the first. Nope. Just been so long the paint wore off and it was disguised as a standard. Now I know I have an extra reduced power and an increased power spring. And a firing pin, and charge handle. (Yikes! Spare parts!)

While and tunable gas key may work well, and be a more expedient solution in some situations, I am happy with my purchase. I am an overthinker. This is peace of mind, literally.

Well, I guess that bring this one to a close.
Stay tuned(see what I did there?) for the range report.:D
 
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