I never realized how loud the action on my AR is until today.

I went to the range and successfully tested a subsonic 9mm load in my 16" 9mm Olympic AR with a Diplomat II silencer.

Wow!!  It is really great!  All I can really hear is the action slam back and forth, and the thud of the bullet hitting the dirt backstop.

Now I'm feeling like the action is too loud!  Is there any way to quiet it down?  I'm using a Fulton Armory lower with an adjustable stock.  I've got whatever buffer/spring they put in it.

When I get a dedicated lower, I'll probably get a better spring and buffer, but what?  Will it quiet down?

Thanks!

Can I run the 2x spring on my 223 upper as well?

Rifle buttstock

if you don't mind using the rifle buttstock then this item will completly remove the spring noise from the cycle action.

www.olyarms.com/?rootView=browse&view=dtl&ids=AC4-NA18

Well, I can't say the action noise is from the spring.  I don't have the annoying 'sprongggg' sound that others experience.  I'm sure it is the normal action sound, but until recently it was hidden by the rifle report.

I can understand the 2x spring might make the bolt hit softer on the way back.  I'm not sure if the oly buffer would make things more quiet for me.  It seems to be designed to get rid of the sprongg sound.

I'd be willing to give something a try, but don't want to waste money.

I was thinking something like the 10/22 or 1911 nylon buffer cuts down on the mechanical noise.

You have a nylon buffer on the back of your buffer already so another nylon buffer is not going to change much.

The silencer is increasing the gas into the sytem, either a stronger spring, or heavier buffer will slow the cycle speed lessen impact sound, you can put an adjustable gas block or tube on the system and turn down the gas to slow the cycle.

Quoted: You have a nylon buffer on the back of your buffer already so another nylon buffer is not going to change much. The silencer is increasing the gas into the sytem, either a stronger spring, or heavier buffer will slow the cycle speed lessen impact sound, you can put an adjustable gas block or tube on the system and turn down the gas to slow the cycle.

No gas block or tube on a 9mm. If he doesn't already have a heavier buffer for the 9mm, he should probably get one. It will decrease the stress to your lower as well as keeping the bolt forward longer which will reduce the gas(Noise) coming back through the upper receiver.

I have an Oly/Glock 9mm setup with a DipII as well. I am having issues keeping the ammo subsonic through the 16" barrel. I have plans to SBR it as soon, so I'm not worying about it to much.

I've had no trouble keeping it subsonic.  I've run 3.2gr of Titegroup with a 147gr plated round nose at 1.146 OAL.

I haven't experimented with how much hotter I can get, but it is definately subsonic and works the action just fine.

No chrono data yet.

height=8

The silencer is increasing the gas into the sytem, either a stronger spring, or heavier buffer will slow the cycle speed lessen impact sound, you can put an adjustable gas block or tube on the system and turn down the gas to slow the cycle.

Huh?  9mm AR's operate via a direct blowback action and as such don't have a gas system.  So adding an adjustable gas block isn't really going to help much is it?  hinking.gif

Quoted: The silencer is increasing the gas into the sytem, either a stronger spring, or heavier buffer will slow the cycle speed lessen impact sound, you can put an adjustable gas block or tube on the system and turn down the gas to slow the cycle. Huh?  9mm AR's operate via a direct blowback action and as such don't have a gas system.  So adding an adjustable gas block isn't really going to help much is it?

Our theory is this:

Basically you have a range with two extremes - one is where you action is very quiet because it does not cycle at all and the opposite extreme where your action is cycling strongly but loud.  Safety first, always.  

So you safely move around in that area where you find your rifle will be quiet enough for you but remain reliable.  You do this by either altering the rifle or the cartridge.  


With the one we played with we experienced significant gains by 1. using a 9mm buffer and 2. using a different powder.    We experienced good results, but yours may vary.  Safety first always.