Few questions on Suppressors

I have never read anything about AR's saying they shouldn't be suppressed. Where is this coming from?

Install can, load and pull trigger, that's it. Attaching a silencer means additional back pressure. An adjustable gas port reduces the amount of gas doing to the bolt carrier, but I have not bothered to install one on my suppressed AR's yet.

Ranb

I have never read any manufacturer disclaimer on shooting a direct impingement AR-15 suppressed without an adjustable gas port. I would recommend them myself though. The only two AR's I have seen with a piston upper came with an adjustable gas port and were well suited to use with a silencer.

Ranb

What they are probably talking about is a "gas buster" latch or something to that effect. It reduces the amount of crud that flies back at you when shooting. You don't need one though.

No, I am talking about an adjustable gas port that varies the amount of gas sent down the tube to the bolt carrier. Something like these for DI uppers; http://www.jprifles.com/1.4.6_gs.php And something like this for piston uppers; http://www.ar15tactical.net/pistons.htm The gas buster charging handle merely keeps gas spraying from the tube from leaking out of the rear of the upper and into your face. I did not notice any difference when installing one on my AR.

It is foolish to not wear eye protection when shooting a semi-auto rifle suppressed. There will always be more gas being pushed back through the chamber due to the additional back pressure associated with silencer use.

Ranb

It's not that you'll get deadly hot gasses in your face, it's that suppressors tend to result in junk getting blown back at you- dirt from the chamber and such.

The gas buster has nothing to do with how the rifle mechanically operates. It is intended to reduce the amount of gas that leaks out of the upper receiver at the rear where you face is. Look here for details on how it works and how to make your own if you are too cheap to buy one. http://www.coloradoshooting.org/gas buster.htm

An adjustable gas port or adjustable gas block varies the amount of gas sent to the gas system whether it is direct impingement or piston operated.

The increase in back pressure in the barrel pushing gas and debris back out into the action is impossible to change other than by reducing the powder charge.

Ranb

So then is this to reduce the amount of gas flying into your face or is this related to the function of the firearm?

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Both to an extent. When you run a suppressor without an adjustable gas port, you are over-gassing the gun (more gas is being used to operate the action than is needed). This can cause increased wear on parts, and it also causes more gunk to build up in the receiver and then send more stuff back at you.

However, there is not as much gunk blown out of the gun (back at you) as you are thinking.

Think wind blowing dirt in your face. That's what it's like when a can kicks junk in your face. Nothing lethal, just annoying.

I have had marks on my face from debris out of my suppressed 458 socom AR-15 that potentially would have blinded me had I not been wearing glasses.

I have a silencer that I let anyone use on their 223/5.56 rifles at the local range. I warn all users that they need to have their glasses on as shooting without them will eventually injure them, especially if they are shooting left handed with a standard AR-15.

Ranb

My buddy recently got a "suppressed use only" SBR upper from MSTN (10") and it has the least gas in the face of any suppressed AR we've shot.

Ranb said:

I warn all users that they need to have their glasses on as shooting without them will eventually injure them, especially if they are shooting left handed with a standard AR-15

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I shot some full auto suppressed AR's chambered for .300 AAC Blackout a few months back and my eyes started to burn from the gas. I was wearing protective glasses but wish I was wearing skiing googles or similar. The barrels were 7", 9" and 12" and all three had AAC supressors.

Gasbuster is a waste, in my opinion. Your eyes are still going to water up with rapid fire and the little 90 degree diversion channel in the charging handle doesn't do much of anything to divert junk. It does help a little if you're shooting something like a Mk12 where you're not dumping mags.

You can always tell your buddies they're tears of joy.

Skribs said:

Okay, so to clarify...

1. Aside from increasing the rate of fire in full auto, the suppressor will not affect the function of the rifle with or without a gas buster, and it will not damage the rifle even without the modification?
2. On a piston AR, is the adjustable gas port for the sake of gas busting or is it required for proper function?
3. Without such a gas buster, I run the risk of crud flying back in my face, so its more important to use eye pro. However, if I need to fire without eye protection available, how much more dangerous would it be than with the gas buster (or just a stock AR with no suppressor)?

EDIT: I had 2 #2 questions. Math fail.

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1) Running a can on a standard DI gun without a adjustable gas block may or may not cause damage and may also have and effect on the function on the weapon. There is no real easy answer as it depends on the system as a whole (Buffer, buffer spring, gas system length/type, barrel length, suppressor type/size ect as well as the can. Standard AR gas systems are notorious for being way over gassed when suppressed and that can cause malfunctions and damage to the weapon (as I said depending on the system as a whole some may be fine others may not). A gas buster will have no affect on function of the rifle it just keeps you from getting as much of that backpressure in the face.

2) On a piston The adjustments allow for proper functioning with a suppressor. On a DI system the adjustible gas block actually helps with both (keeping your gun from being overgassed and reducing some of the gas blowing into your face. You'll still get some backpressure no matter what no matter if you have a adj. gas block or piston system.

3) It won't kill you but you may not be happy after shooting A LOT with no eye protection. Remeber you still get crud coming back with no suppressor on a DI rifle anyway I've had the line on my face after shooting a lot of rounds in a day to prove it.