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Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Tue, 07 Apr 2015 21:32:43
by MarcSpaz
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I am pretty stoked. My 300 Blackout SBR is finally done!!!
SIG Arms lower
SIG Arms Mil-Spec LPK
SIG Arms STL-900 flashlight laser combo
Geissele Automatics Super Dynamic Enhanced Trigger tuned down to 2.5 lbs
Geissele Automatics Nitride Low Profile Gas Block
Magpul MOE SL stock
Magpul MOE-K2 Grip
Magpul Polymer FUBUIS
EOTech Sight and Magnifier (NV Compatible)
Advanced Armament Co upper receiver
Advanced Armament Co 9 inch barrel
Advanced Armament Co 762-SDN-6 Silencer
Knightâs Armament free-floating guard
GI Mags
I'll get some better pictures in the sunlight tomorrow.

Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Tue, 07 Apr 2015 21:47:48
by SHMIV
That looks like fun. You'll have to let us know how it does.
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Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Tue, 07 Apr 2015 22:10:22
by MarcSpaz
Oh yea... Might go to the range tomorrow and break it in.
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Wed, 08 Apr 2015 08:16:56
by OakRidgeStars
Congrats! Nice build.

Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Thu, 09 Apr 2015 00:55:41
by MarcSpaz
Hey guys,
I shot a quick video at the range today. Sorry about the video quality and lighting. I used a high-def camera, but it was extremely dark at Range 82 because it was raining pretty hard and I don't have good video editing software anymore, so I couldn't clean it up very well
Basically, my son and I shooting the 300 Blackout, then we moved the can to my SIG 516 (5.56mm) and my SIG 716 (7.62mm/.308)
www.youtube.com/watch?v=s5AoBpp8Qf0
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Thu, 09 Apr 2015 05:59:07
by M1A4ME
Nice looking gun.
I wanted to do something like that a few years back. Got the rifle built (16" barrel) but never got around to the paperwork or sending the upper off to have the barrel shortened/set up for a suppressor.
Maybe "one of these days".
Now we need to see some targets and description of the loads you use. You know, to spur the rest of us on.
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Thu, 09 Apr 2015 10:22:11
by 0ne5hot
Nice setup Marc...I really need to get the paperwork done for my pistol
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Thu, 09 Apr 2015 11:32:30
by MarcSpaz
Thanks for the kudos. Man, this BO is so much fun to shoot.
I was shooting over the counter ammo at the 7 yard line. I get 300 BO rounds pretty cheap from VA Arms; about $0.70 a round if I by a box of 20, then a volume discount if I buy a case.
Next time I go, I am going to zero the EOTech at the 100 with hypersonics, then do performance testing with the subsonics. It will probably be a few weeks. I am having surgery on my neck in about 4 hours. I don't know when I'll be comfortable enough to shoot prone again.
The only paper I saved from yesterday was my target from the 200 yard shoot point. This was with my M4. I was pretty impressed with it. This was the first time I fired the M4 with the Burris scope on it, so there was some zeroing going on in this picture, but once I got in dialed in, I was making nice groups.

Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Thu, 09 Apr 2015 13:45:16
by 0ne5hot
Most of what I have seen shows 100' zero with with supersonic, should have you roughly zeroed at 50' subsonic.
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Thu, 09 Apr 2015 20:14:31
by minininjer
Awesome looking rifle!
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Thu, 09 Apr 2015 22:00:07
by MarcSpaz
Thanks! Its a good time to shoot, for sure. Likely my favorite weapon I have ever owned.
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Fri, 10 Apr 2015 16:46:30
by RO73
Very nice. I'm currently building a 10.5" 300blk suppressed SBR as well. I have everything except the SDN6. It's still in NFA jail.
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Fri, 10 Apr 2015 17:13:52
by MarcSpaz
RO73 wrote:... I have everything except the SDN6. It's still in NFA jail.
Hahaha... I literally laughed out loud.
You are going to enjoy it. Looking forward to seeing the pics once its done.
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Sun, 19 Apr 2015 12:07:26
by bryanrheem
this is the build I am working on right now (more like saving for!). I actually have the lower and can, just need to get the upper built, or bought.
Are you going to start reloading or do you think you can keep up with .70c per round?
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Sun, 19 Apr 2015 17:12:44
by MarcSpaz
I can afford it no problem. I just don't know if I want to. I want to buy or build a .338. Those 2 rounds together may be just the insentive I need to take a reloading class.
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Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Sun, 19 Apr 2015 17:14:15
by MarcSpaz
Now that I think about, making my own sub-sonic .308's and .223's would be nice.
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Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Mon, 20 Apr 2015 07:51:25
by RO73
MarcSpaz wrote:I can afford it no problem. I just don't know if I want to. I want to buy or build a .338. Those 2 rounds together may be just the insentive I need to take a reloading class.
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Building a 300blk is what lit the fire under my butt to start reloading. I am still new to it as I have a good friend showing me the ropes. The possibilities are endless in making custom 300blk loads. 308 is another good round to load as it suppresses pretty well. 5.56, not so much when it comes to subsonic.
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Mon, 20 Apr 2015 09:54:28
by MarcSpaz
I put around 300 rounds through the gun in about 15 minutes and while the rifle was on the bench, the coating on the can caught fire. Not bad. Just 2 or 3 little flames for a couple of second. Is that normal for this weapon?
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Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Mon, 20 Apr 2015 11:19:28
by RO73
MarcSpaz wrote:I put around 300 rounds through the gun in about 15 minutes and while the rifle was on the bench, the coating on the can caught fire. Not bad. Just 2 or 3 little flames for a couple of second. Is that normal for this weapon?
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Holy *#@*. I'm not sure that's normal. You should call AAC and ask. Please keep me posted.
Re: Suppressed 300 Blackout 9" SBR Is Finally Done
Posted: Thu, 30 Apr 2015 12:43:54
by RO73
MarcSpaz wrote:I put around 300 rounds through the gun in about 15 minutes and while the rifle was on the bench, the coating on the can caught fire. Not bad. Just 2 or 3 little flames for a couple of second. Is that normal for this weapon?
Holy *#@*. I'm not sure that's normal. You should call AAC and ask. Please keep me posted.
Did you ever call AAC and ask? I'm very curious as I'm waiting for my SDN6 stamp to be approved.