300 BLK set up for subs and supers - Page 1

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[ARCHIVED THREAD] - 300 BLK set up for subs and supers

Posted: 6/22/2017 12:05:16 PM EDT

Was just perusing Trijicon's ACOGs and was looking at their 4x32 with the 300 BLK reticle. The markings claim to be set up for both sub and supersonic rounds, with different scales on each side. This got me wondering: is there an ideal set up for a 300 blackout to send both subs and supers through (barrel length, gas system, etc)? I was under the impression that you should build for one or the other?

Posted: 6/22/2017 12:45:03 PM EDT

[#1]

my experience was one upper for subs/supers:
Subs: 220gr from either FOG ammo or Ozark
Supers: 147gr Ozark Ordinance target ammo, sometimes 150gr Freedom munitions

I used an Aimpoint PRO. From memory, the delta at 100Y was almost exactly 15MOA. So i marked the spots on my PRO and adjusted depending on what I was shooting.

Worked well.

I bought a 6.5G SBR upper, now I just shoot subs in 300BLK

Posted: 6/22/2017 1:59:08 PM EDT

[#2]

A .300 Blackout it at its best with a 9", pistol length gas system, and suppressed.

I have a 8" Mr Blonde barrel with a KX5 and it operates wonderfully!

Posted: 6/22/2017 2:05:42 PM EDT

[#3]

Quote History

Quoted:
A .300 Blackout it at its best with a 9", pistol length gas system, and suppressed.

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For subsonics right? Do you shoot supersonic rounds through it?

Posted: 6/22/2017 2:06:23 PM EDT

[#4]

Quote History

Quoted:
my experience was one upper for subs/supers:
Subs: 220gr from either FOG ammo or Ozark
Supers: 147gr Ozark Ordinance target ammo, sometimes 150gr Freedom munitions

I used an Aimpoint PRO. From memory, the delta at 100Y was almost exactly 15MOA. So i marked the spots on my PRO and adjusted depending on what I was shooting.

Worked well.

I bought a 6.5G SBR upper, now I just shoot subs in 300BLK

View Quote

What length barrel and gas system were you using?

Posted: 6/22/2017 2:21:32 PM EDT

[#5]

Quote History

Quoted:
What length barrel and gas system were you using?

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View All Quotes

Quote History

Quoted:

Quoted:
my experience was one upper for subs/supers:
Subs: 220gr from either FOG ammo or Ozark
Supers: 147gr Ozark Ordinance target ammo, sometimes 150gr Freedom munitions

I used an Aimpoint PRO. From memory, the delta at 100Y was almost exactly 15MOA. So i marked the spots on my PRO and adjusted depending on what I was shooting.

Worked well.

I bought a 6.5G SBR upper, now I just shoot subs in 300BLK

What length barrel and gas system were you using?

oops, forgot that info.

It is a 12" PSA upper (for sale on the EE by the way!) with FN CHF barrel. "1/8 twist with M4 barrel extension, Pistol length gas system."

I now have a 10.5" Faxon 300BLK for just subs once I finish a few more supers I have left.

Posted: 6/22/2017 4:47:04 PM EDT

[#6]

Quote History

Quoted:

For subsonics right? Do you shoot supersonic rounds through it?

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Works well with both

Posted: 6/22/2017 5:22:15 PM EDT

[#7]

I got an adjustable gas system and found a spot where it run both supers and subs. Since there's such a huge difference in gas it'll never be perfect for either. However I have to say now that I've been shooting my 300BLK for a while I'm dumping my subsonic ammo and sticking with supers only. I'm not happy with the subsonic performance and think it's worth the extra noise for superior performance of the supers. So now I tuned the gas system for supers only. I use this setup for hunting and home defense. Still quieter than my 5.56mm setup.

Posted: 6/23/2017 7:38:52 AM EDT

[#8]

I don't have a suppressor but it's my understanding if that's what you want to do then stick with a short barrel.

My 16" .300blk upper ran supers & subs right out of the box with std. bcg & buffer (fixed gas block, pistol system). I normally run supers with an H3 buffer in it.

My 8" .300 upper ran supers fine but not subs (also fixed gas block & pistol system), had to go with an AIM lightweight BCG & std. buffer. When I run supers I swap in an H3 buffer as well.

Posted: 6/24/2017 5:05:05 AM EDT

[#9]

My AAC 16 inch upper runs both supers and subs without a hitch.

Posted: 6/24/2017 5:36:07 AM EDT

[#10]

I have a 15 inch carbine length cas system that will only cycle subs with a can on it. I am ok with that since subs are pointless (in my mind) with out a suppressor.

The 8.25 inch pistol gas will run both. But i recently re tuned it to only cycle subs with can. Running supers in that setup was beating up the gun.

I use that ACOG on the SBR and the reticle works pretty damn well. If I recall correctly, the ACOG will line up just about pfefectly with a 16 barrel running the 110 to 120 class bullets as supers and 208 to 220 bullets as subs.

Posted: 6/24/2017 2:17:51 PM EDT

[#11]

I just finished my 300 build and thought I would give my opinion. I have a 16 inch barrel with a pistol length gas tube and a H2 buffer and it will cycle subsonic ammo just fine. I think a lot of the problems with 300 blackout is the earlier factory builds had carbine and mid length gas tubes which are not ideal for this caliber for subsonic ammo. Also if you are having trouble with extracting your brass make sure to upgrade your extractor spring.

[ARCHIVED THREAD] - 300 BLK set up for subs and supers

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