Has anyone here used one?

If so please share your experience.

I have used on m1a and tokarov rifles - this allows me to tune the gas system to "just" operate with specific ammo. For example, "We" were concerned about the spam can 7,62x54r, as the Toks are considered fragile and parts were VERY rare. So, we turned ours down to nearly closed and slowly opened enough to operate .. false alarm, but now I had my rifle set at one click over minimum, and that worked for nearly everything else...

secondly, i also knew that i had to adjust for reloads vs milsurp .. i forget the settings, and the tok is one of the few i am sad I sold ... but it was different than milsurp.

I haven't, as yet, put one on ar platform, though I can't imagine the results will be much different, even if the operations mode are.

When you mention "gas Key", I automatically default to the AR direct impingement system, either AR15 or AR10flavor

"Adjustable gas key" triggers lots of thoughts-mostly not favorable. The AR family obtains operating energy from a gas port drilled into the bore, then directed to the gas piston features of the bolt/carrier ( Yes, the bolt is the fixed piston, the carrier is the moveable gas cylinder.

Since the gas/energy is already moving to the operating components, occulding the gas key passages seems rather useless. The energy is going to push on the moveable carrier one way or he other if you think about it- the gas/mass momentum must be expended at least partially against the valve of this adj key, which in turn is mounted to the moveable gas cylinder- the carrier. Just don't see how mechanically it would really be of much use. Any reports on said adj gas key?

All said, if you are writing about some other sytem, like the M1A or M1G or any of many others, I could see utility- the M1A has been modified to allow excess gas/energy to vent, the M1 has several versions of vented or adj volume plugs etc. In my experience with the M1 Garand the Schuster version works well with heavier than standard (175+) bullets and or slower than spec powders (slower than 4895 to 4064 range). I don't go there powder wise, but I know other heavy bullet shooters who do - H4350 being a favorite with 180-190s-but not HOT loaded.

I cannot outshoot a 175/185vld and 46 grn of H4895 at about 2500 fs anyway, and they stay super sonic well past 1k- my outer limit.

that't not a actually how it works ..

you are closing down the hole, effectively reducing the diameter of the gas port - which, if you read the post on my quasi-dissipator, you will see is a real issue... the forces actually don't play on the parts, and you can turn these gas system complete off to full.. they are a valve, not unlike the wall faucet attaching the garden hose.. turn it up out down, and you get a difference in work from the flow.

since these act over VERY brief times and varies the size of the port, you can tune these to zero to operate to overgassed.

(sigh) - i've been in a karate tournament fom 945 until 20:15 - i am tired and a bit grumpy

Jeffe
I think you are talking about an adjustable gas block on the AR type rifles.

They can be very useful for tuning a rifle for a particular load, and also for reliable function with a suppressor.

Nope!

He is talking about the gas key

This is a cheap part that bolts on in minutes

Or you can drill and tap a mil-spec oem part

These parts are a great alternative for the guy that has A2 front towers and wants to tune his bolt speed

Do they work?

I hear they are impressive!

Anyone have any testing reports on these gizmos? I am doubtful and from MO, so show me!

I still think all the gas energy will be spent on the moving mass of the carrier group, doing the same kind of work, maybe less efficiently.

I slow up things by using a Tubb Carrier weight system- inserts into the rear of the carrier and adds mass to the carrier, more mass means slower movement in both directions. Fixed brass life problems while using heavy 80 grain bullets for 600+ in service rifle competition.

Using an adjust bale port gas block would work I agree, but this concept-not so much....

Not worth an argument either way though!

You do know that the AR15 bolt is not a blow back sytem right? Your above statement leads me to feel that you have good knowledge of the AR gas system

M16 bolt.....extra power buffer spring.....H3 or 9mm buffer

These were all the ways a guy could slow the bolt in the past now there is yet one more cheap and quick option

Especially for guys.....like myself with A2 sight towers

Gas flows through the key.....it doesn't end at the key

The adjustable key allows for flow adjustment like a valve....simple

quote:

Originally posted by N E 450 No2:
Jeffe
I think you are talking about an adjustable gas block on the AR type rifles.

you are right -- (sigh)

SOrry HPmaster - i went off, and was wrong

No problem-

Ted, yeah, kinda knew it wasn't BB. But th gas pressure/energy pushes the carrier mass rearward- is not the key attached to the carrier? And since it is, occluding it would make the gas expend its energy against those occluding surfaces-doing work of some value. I do not really think this arrangement is a valuable solution-cut the port the right size if you are interested in controlling gas, or use an adj fixed block system.

The gas pressure in the ar does not keep the bolt locked- only the delay in movement of the carrier movement accomplishes that , by turning the cam/bolt and then withdrawing the bolt to extract etc.

Using a throttled port attached to the moving mass one wishes to retard/delay seems silly to this engineer.

Not to this one...besides if you read my post I'm interested in these for rifles with A2 pinned sights

Not loosing any sleep that your not convinced....this you can trust

Ted,

Send me a link with info, I'm happy to learn more about it.

Look at superior shooting systems carrier weight system if you wish- adding mass eases the stress on brass and extraction.

I used to ruin brass with heavy loads extracting under pressure until going to a Tubb CS spring and weight system, 100% reliable ( full power) but softer in both dwell and speed.

I shoot a fixed A2 FSB as well- NM AR15A2 Service rifle.

Best;

I know all about adding weight to the bolt, buffer and extra power buffer spring

btdt....it works great but at a higher cost per rifle and is not tunable for multiple loads