AR-15 Suppressor - Adjustable Gas Block Required?

I've just purchased a new DPT suppressor for my Rock River Arms AR. It's an "Entry Tactical" model which is carbine length with 16" barrel, standard front sight gas block. I've never shot a suppressed AR before and I've heard they often have gas issues (overgassed) and need adjustable gas blocks to reduce the gas flow. Am I likely to need to invest in one or have people found it not necessary? I'll take it out this weekend and find out for myself I guess but thought i'd first see what everyone on here has experienced on similar suppressed AR's.

Cheers
CT

Nope, fitted my DPT straight on and went shooting, no issues at all.

I'd never noticed any "over-gassing" when using a suppressor UNTIL I fitted and tuned an adjustable gas block today. Obvious difference in felt recoil. Well worth doing.

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Gas blow back through the action is more of a problem when fitting a suppressor. A DPT should have enough capacity to reduce this a bit, better still if it's over barrel model. Check your rounds in the mag after firing a couple, if they are really dirty, this is blow back. I did fit a Syrac adjustable block to my RRA and it reduced felt action recoil.

You may not NEED it depending on the kind of shooting you do. Using a heavier buffer makes a difference when shooting without an adjustable gas block. An adjustable block does more than just reduce gas in your face. You can tune your gun to get just enough gas to cycle well, which will cut felt recoil significantly, and increase the service life of your bolt. Standard gas block vs adjustable will make it feel like a different gun

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Originally Posted by Beavis

You may not NEED it depending on the kind of shooting you do. Using a heavier buffer makes a difference when shooting without an adjustable gas block. An adjustable block does more than just reduce gas in your face. You can tune your gun to get just enough gas to cycle well, which will cut felt recoil significantly, and increase the service life of your bolt. Standard gas block vs adjustable will make it feel like a different gun

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I've sold maybe a dozen adjustable gas blocks on this forum, and only just got around to fitting one myself. Can't believe the difference. Should've done it sooner.

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Thanks for the replies team. Any recommendations on the best brand/type to go for other than the Syriac Mathias used? I'll be using the suppressor all the time so don't think i'll need a fancy one with a switch for suppressed/non suppressed.

Superlative Arms

IMO DPT cans are not good for gas back, even with an adjustable gas block.
This is my experience on a number of ARs, different barrel lengths, calibres and with and without adjustable blocks.
Gas busting the charging handle helps.

I wouldn't buy another for use on a direct impingement AR.

If you can, get the Superlative Arms bleed off block. It can bleed off or pinch the gas system to suit the user.

I went through the exercise recently and found that a heavier buffer and an adjustable gas block transformed my carbine. Before hand, it recoiled reasonably hard and there was a lot of gas coming up under my safety glasses making my eyes water. It is a lightweight carbine with 12.5" barrel and after 50 odd rounds it was becoming unpleasant to shoot with watering eyes and a yellow bruise forming from the plastic Armaworx stock. My suppressor is an ASE CQBS-BL which is a compact unit and as a consequence creates greater back pressure. I first moved to an H3 buffer which slowed things down about 10% but the best thing I changed was the gas block. A Dean Maisey adjustable gas block softened the recoil, eliminated the gas and allowed control of the brass ejection to land in a sweet little pile at 4:00 so I don't have to grovel around in the grass at the range. Don't get those horrible little cheapo gas blocks on TM as my one seized after 20-30 rounds because of the grub screw being too small. Dean's gas block has a massive adjustment screw which is indexed so you can easily alternate between different applications and will not ever seize.

I run a Seekins adj gas block on my 16" spikes and it has never given me any issues.

Ken at NZAR15 is your man if Stretch has run out

Have a little read about why/how/sexytime: https://www.nzhuntingandshooting.co....ks-ar15-25570/

Hmmm interesting. Might go by one now and see if it makes a difference

As @Beavis mentioned you are prolonging the life of your rifle and working parts. Why hammer them with over gassing?

Rifle should be balanced when using an adjustable block, with or without a suppressor or a change of load anyway. 9/10 times if done properly it doesn't matter what buffer spring you run. Heavy buffer springs can be avoided with a good block as they can increase felt recoil and disrupt quick sight alignment.

Restrict the gas flow by screwing the adjustment screw in until the rifle doesn't cycle. Wind out, half a turn until it the BCG locks back firing one shot from the mag at a time.

Once you have achieved lock back wind her out another half turn confirm it cycles with a few rounds and lock the set screw. Rifle is now balanced for the particular ammunition you are using with or without a suppressor.

I balance my rifle when ever I fit a suppressor or remove it. And especially if I ever change my load.
Makes for a flatter shooting rifle that is not overworking the guts.
My JP when properly balanced and using a break is like firing a 22 apart from the noise.






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I'll be using mine for service rifle class which unfortunately means I can't use an adjustable gas block. The results you guys are describing sound quite beneficial!

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Originally Posted by Danger Mouse

I'll be using mine for service rifle class which unfortunately means I can't use an adjustable gas block. The results you guys are describing sound quite beneficial!

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Interesting. I have never shot service match as civilians do it but I take it you can use an L1A1, FN or AUG in service match?
They're all adjustable. Does the rule only apply to AR platforms?
Or is it depending on class?

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To those who are going to fit an adjustable block do not skimp on a cheap one.

Get one, that once set, can be secured by a grub screw or other means.

And periodically check the function of the set screws etc as they will carbon up and you will never get them undone in order to adjust them again.

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Originally Posted by R93

Interesting. I have never shot service match as civilians do it but I take it you can use an L1A1, FN or AUG in service match?
They're all adjustable. Does the rule only apply to AR platforms?
Or is it depending on class?

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@R93 to be elligable to shoot in "service class", the rifle has to be "as issued". You are welcome to shoot open class with anything though.

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Originally Posted by Beavis

@R93 to be elligable to shoot in "service class", the rifle has to be "as issued". You are welcome to shoot open class with anything though.

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Cool. Makes sense. Just minus the select fire option tho eh[emoji1]

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I’ve modified a few std ones by drilling and tapping. Fit a grub screw . Once set use a pin punch to stop the pin moving. I have dean maiseys adjustable one on one of mine and have fitted a few. They work really well. Are detented so no grub screw required which is what others are doing now in the us. I saw quite a few rifles at the last 3 gun match running too fast and had feeding issues on some fast 80 round stages. Using a heavier buffer on carbine buffer tubes definitely makes a huge difference as others have pointed out. I currently have the JP silent capture in mine and are pretty much the ducks nuts for quietness and fully tuneable for weight and spring pressure.

Sorry to drag this old thread up, but I need some help, I’m going to get a adjustable gas block for my RRA lar-15 is has a heavy varmit barrel on it, I can find anywhere what size block I need, if anyone knows please let me know. Also,what size would go on a 16” ranger? Any help is much appreciated.

@Fat ninja if your AR has a really heavy profile, you may need a .875 or .936 gas block. I assume your Ranger would have a .750 journal

@Beavis I finally heard back from the factory last night, they said it will be .936, I’m thinking the ranger will be .750, cheers for your help