Quietest 300 BLK Subsonic Round for Daniel Defense M4 ISR

[Dolomite_Supafly]

Unless you spent thousands on your sound meter it will likely not be very accurate. Most of the cheap ones listen for noise THEN start recording. By the time it starts recording most of the gunshot noise is already gone. What I have found to work really well is using a computer with a recording program that you manually start recording then you shoot. The program has a running graph that measures the peaks so it allows you to the shots. You will not get a decible number but it will allow you to compare oranges to oranges. The one obstacle is getting a decent microphone that will record a gun shot accurately.

An AR is never going to be really quiet to the shooter. The quietest loads will be using a single shot or bolt action. With those you can use really fast burning powders. I have spent a lot of time trying to figure out a quiet AR load as well as trying different modifications to the gun itself trying to get it quiet. In the end I realized that there is no way an AR is going to be as quiet as a single shot.

Of all the guns I have owned chambered in 300 Blackout my Encore with a 16" barrel is the one that gets shot the most because it is the quietest. It is, literally, quieter than a slingshot. With a single shot gun you can also load lightweight bullets behind a minimal charge to get shots that are magical because of how quiet they are. I use 90 grain XTP bullets loaded using fast powders to a velocity of ~800 fps and I swear I can hear the hammer fall over the sound of the shot.

Blue Dot loads are about as quiet as it gets in an AR or at least in MY AR using MY silencer. The only problem I have found with using Blue Dot is any load that will cycle a short AR will go supersonic in longer barrels. But I like it so much I use it for a lot of my single shot loads.

[mxjoe35]

Thanks for the info Dolo. I definitely did not spend thousands on a sound meter...more like $30! lol


So it may not work very well, but it was worth a $30 shot, before breaking the bank. If it doesn't work, then I will look for a computer program. Also I get that my AR will never be as quiet as a bolt action, but it's what I have so I'm trying to get it as quiet as possible. Down the road I am going to get a separate suppressor and some bolt actions. I ordered my Caldwell Chrono, it comes tomorrow and I have loads ready to test. I am in the processes of building a bullet trap, so I can test in my basement. Getting some prices on some AR500 steel. So hopefully later this week I can start some testing!

[Flatliner]

I have had pretty good luck with DecibelX as a phone app. It's worth a try as it is free and you can plug an external mic into the phone if you want. It just runs and then records peek level so the time issue isn't a problem.

[mxjoe35]

Cool, thx! I will run it side by side with my $30 db checker and see how they compare.

[Dolomite_Supafly]

You could also install an adjustable gas block and tube the gun. That can help a lot.

[mxjoe35]

So the wife was out of town with the kids...so what else am I going to do but call my buddies and do some test shots in my basement! LOL I told my buddy I needed him to come over because I built a home made shooting range in my basement, and was planning on shooting a bunch of rounds I just made...which were the first rounds I have ever made and I needed him just in case shit went sideways to drive me to the emergency room! LOL So I built a bullet trap (hoped it would work!), shield wall (just in case it didn't!) and a trashcan suppressor with egg crate to help suppress the sound of my first un-baffled shots. I would make my first shot of each batch un-suppressed to make sure the bullet acted right (no keyhole-thanks to advice i got here), before putting my baffles back in and shooting the rest of my batch. The first thing I did was take some shots with Remington 220 and Hornday A-Max 208 Gr subsonic rounds to give me a baseline of sound. I then started down the list from 10 grains to 7 grains of Hornady lil-Gun. This is not scientific by ANY stretch of the imagination, but I just collected some data points and mainly wanted to see if my first ever rounds hand loaded would fire. The good news, they did fire and were fairly consistent. I am going to continue loading some more rounds, I need to test them outside with no concrete walls and dinging of bullets hitting the plates.

So here is some data: http://www.keepandshare.com/doc4/view.p ... 02907&da=y

Video: https://youtu.be/x8X_y-vWlkg

Shooting Range:

[dellet]

Great set up MxJoe35. That looks like a great place to spend a rainy day.

Data looks like it's a sign up to read, any way of getting some posted?

[bangbangping]

Awesome! I especially like the stick figure of your wife's reaction when she finds out you've been shooting in the basement.

[mxjoe35]

Ahhh crap, I was looking for a free PDF host site. Let me find another one.

[mxjoe35]

bangbang...I hope that's all i get! LOL