What does it take?

A much smaller gas port then what most of them are made with and/or a gas piston setup. Any direct impingement design is going to be dirty by nature.

Is it possible to get a gas block that will choke things down enough to still run?

I had a Ruger with a 4 position and it was just as dirty as my non adjustable block AR.



Do you risk clogging up the piston system running suppressed?

Suppressed DI guns are just dirty. I have a long stroke piston JAKL and it is extremely clean running suppressed compared to my DI guns. Just the nature of the beast.

First off, suppressed guns run dirtier, both piston and DI (I have both). Second, an adjustable gas block will help you to tune them properly. What I mean by that is slowing down the BCG, and reducing the gas back through the port.

I have used SLR for several years, and recently tried Riflespeed. The Riflespeed is heavier, but easier to adjust. For the Riflespeed, you have to make sure you pick the right one based on your gas system length and handguard length. While I've never had an adjustable gas block cause a failure with the firearm, they do tend to lock up if you don't run them through their adjustment range periodically.

Turn down the gas until you get 3 to 4 o'clock ejection. And it's going to be dirty anyway.

My LR-308 is on a hand load of course. It was ejecting at 1 to 2 o'clock. An adjustable gas block got it ejecting properly. And it still gets filthy after less than 5 rounds. If I run a 10 round mag through it, I immediately pull the bolt, wipe it clean, as well as the inside of the upper and reapply oil. It is just how it is.

75% Mobil-1 5W-20
25% Automatic Transmission Fluid

The transmission fluid stinks when it cooks off, but that blend has been the most reliable lube I've used to date.

You can run a different powder that will burn cleaner and/or have a more complete burn. I have some SBR loads that accomplish this. 98%-99% burn in 10" of barrel. You sacrifice a little velocity, but you gain in cleaner burn and cleaner AR.

I remember bringing this up a few years ago and folks on here were in complete denial about it. Silencers and gas guns are a bad combination for a defense rifle. There are things you can do to limp them along but they will never be as trustworthy as a gun without one on it. I’m referring to trusting your life to it rather than shooting pigs or paper.

It can be done but the gas port size, buffer spring weight, and buffer weight have to be picked for use with a can and what works with a can will be under gassed, over sprung, and over buffer weight for use without the can. People just can't get it through their heads that the AR is a mediocre design that starts to have issues if you go outside of its original design parameters.

My work rifles are spec'd to be suppressed and they are dirty

That might be the first time I've heard the AR called mediocre lol.

I respectfully disagree. I'm not about to call the most reliable, and widespread design mediocre. I basically run my ARs exclusively suppressed and maybe clean them every few hundred rounds if I'm bored. If the bolt feels a little sticky to close I'll toss a few drops of oil on there.

I think people sometimes mistake a gun being dirty with being unreliable. You should see the gunk that I clean out from my competition guns sometimes. A good design will prevent or move the carbon out of the areas where it can have an impact, or will be appropriately clearanced to deal with it. The AR is a great example of this, and will continue operating well beyond what might look dirty.

AR’s are dirty. Your selection of barrel length, ammo and if you reload then also the powder can affect the amount of soot and unburnt powder. The type of lubricant you use also makes a difference in attracting/collecting debris. The use of an adjustable gas block will help by allowing you to tune amount of gas to just enough gas to properly operate the BCG. The moment you screw on a suppressor things get really dirty as the can restricts majority of gas from blowing straight out of barrel… more gas ends up being pushed back to the chamber.

AR is going to be dirty. Converting it over to a piston system just shifts some of the soot away from the receiver and into the piston mechanism. Regardless, if you shoot AR’s (suppressed or not), you have to clean them and like all semi-autos there is more dirt and more places that need cleaning. Fact of life…

Tuning the gas block is important. Without the suppressor attached, reduce the amount of gas through adj. gas block to as low as possible while rifle still reliably function. Make sure that BCG extract/eject spent brass and then strips and loads next round as well as BCG holds open after last round fired. If you are shooting both supersonic and subsonic ammo through the rifle then set up gas block based on the subsonic ammo, which generates the least amount of gas volume. Now, whether you use suppressor or forget it at home, your rifle runs.

The AK-47 might have something to say about the "most reliable" statement.

As well as the "widespread" statement, when we are talking about the globe.

I would argue in favor of a roller-delayed blowback system like a G3 for thr most reliable, but not nearly as common. Malfunction might be more common but if you can get a roller lockers bolt closed it will blow whatever gunk you grt in there clean-out in a few shots

Due to malfunctioning firearms during qualifications, most large police departments have disallowed the use of silencers on AR-15 patrol rifles.

Genuine curiosity - what type of malfunctions were occurring as result of a suppressor on an AR15? Would you characterize the weapon malfunctions as parts breaking, such as the Bolt Stop or Buffer Retainer Pin?

I think that issues with Suppressors are far less common then just normal AR rifle issues resulting from poorly balanced buffer systems or inferior parts. If you add a suppressor to a marginal rifle then the additional force (back-pressure on the BCG and Buffer System) will highlight any faulty components. I have seen this, especially on entry-level, budget friendly AR15's. Not all rifles and components are made to the same standard.

I wouldn't simply screw a suppressor onto an AR without giving some thought to additional back-pressure and if the rifle's buffer system is capable of handling it. The additional back-pressure can be addressed by either reducing the amount of gas redirected through the gas system &/or beefing up the buffer system. If I don't know the components of the buffer system or its a cheap budget rifle then automatically upgrading the Buffer Spring ($15). The easiest fix for excess gas volume is to install an adjustable gas block. A quality adjustable gas block, such as SLR Rifleworks or Superlative Arms, makes short work of the excess gas pressure and also reduces excessive wear and tear on parts. . The least expense fix is to start swapping out buffer weights and springs, which may be a trial and error process with a couple of trips to the range to sort out.

Thanks

Adding a can to an AR doesn't raise the peak pressure. It increases dwell time which is how long the port sees higher than ambient pressure. Making the barrel longer after the gas port does the samething. Using slow burning powders can also do the samething.

Piston guns will go a lot longer between cleanings than any DI. That is about all you can do.

Just to kick the hornet's nest a little.



How do you think the AR did in the same test?

A piston.

A bolt action.

The barrel extensions is too small and that forces the bolt and the lugs on the bolt to be too small. The bolt being small also forces the extractor to be too small and it is weak. The bolt is weak at the lugs and cam pin hole. The receiver extensions prevents making the system very compact and the bolt carrier group is twice as long as it should be which forces the receiver to be longer and that also makes it tough to have a compact gun and still have a decent barrel length. The gas tube is fragile and if damaged or cloged it takes the weapon out of service. Overall in its original form it is a relatively elegant and simple design and it's original intent was to showcase new at the time materials and manufacturing techniques. It is a design that should have been left in the past. Despite all of that I own dozens of them and if you want a weapon for self defense you would be foolish to pick any other long gun if you live in the US.

And yet we are transitioning into SBR’s and suppressors.

lol

lmao even

It's funny... I'm more worried about what shooting suppressed does to my brass than the actual gun. IMHO, steel pin tumbling is a necessity for getting all that crap off your brass. At least for me. YMMV (and will, I'm sure).