Finally, the perfect (compromise) 300 BLK AR

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bangbangping
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Finally, the perfect (compromise) 300 BLK AR

Post by bangbangping » Wed Oct 23, 2019 5:04 pm

So far I've owned a bunch of 300 BLK AR's from 8" to 16", a bolt action, and a CVA pistol. This will likely be my last 300 BLK AR.

I've always thought 16" barreled rifles were unwieldy with a suppressor attached. And although it was handy, I was always disappointed in the noise level of subs that would cycle the 8" AR. This one addresses both of those issues.

Key features are:
11.5" BHW barrel. Not too long, not too short. Just right. Based on other BHW barrels I've had, it should shoot very well.
Slick side upper with an extended slot machined (I still need to blacken it).
Bolt carrier drilled/tapped and side charging handle installed (Bought the handle as a replacement part from Midway, about $15)
Adjustable gas block.

My theory:
1. An 11-12" barrel will obtain 95% of the velocity of a 16" barrel. That's fast enough for most purposes. If I really need something faster I can use the bolt action or another caliber.
2. It will be quieter with subs than, say, an 8" barrel.
3. Still convenient enough to carry around with a suppressor attached.
4. With the side charging handle I can shut off the gas, shoot fast powder quiet subs, and still cycle the rifle quickly if needed.

It should make a great 200 yard hunting rifle with the Gold Dot, or a nice quiet sub rifle for closer ranges. Interestingly, the BHW barrel has the option of a proprietary gas length that's in between pistol and carbine. I'm sure it will cycle supers. The subs I'll shoot wouldn't cycle any AR, so no sweat there.

It's the top one in the pic. 18" AR below for comparison.
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TRshootem
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Re: Finally, the perfect (compromise) 300 BLK AR

Post by TRshootem » Wed Oct 23, 2019 9:56 pm

Nice! I like it, my 16" Hardened Arms carbine gas was stupid accurate but a bit over gassed. Adjustable gas blocks were not really with it yet at that time. I sold it to do another build, now just have a RARR and 10.5" pistol. Look forward to hearing about the meat in the freezer.

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dellet
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Re: Finally, the perfect (compromise) 300 BLK AR

Post by dellet » Thu Oct 24, 2019 9:28 am

I have been very pleasantly surprised at the reliability of my 10.5” carbine gassed upper with subs. The difference in port noise is huge. Velocity is adequate with supers.

With a 7” suppressor it’s still just a bit shorter than a 16” barrel with a muzzle device.

Did you get their custom gas length?
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Re: Finally, the perfect (compromise) 300 BLK AR

Post by bangbangping » Thu Oct 24, 2019 10:44 am

dellet wrote:
Thu Oct 24, 2019 9:28 am
Did you get their custom gas length?
Yes, I did. Just finished assembling and haven't had a chance to shoot it yet.

I may work up some subs that will cycle, but that isn't my main focus. I'll be shooting subs with the gas turned off more often than not.

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Re: Finally, the perfect (compromise) 300 BLK AR

Post by dellet » Thu Oct 24, 2019 1:23 pm

bangbangping wrote:
Thu Oct 24, 2019 10:44 am
dellet wrote:
Thu Oct 24, 2019 9:28 am
Did you get their custom gas length?
Yes, I did. Just finished assembling and haven't had a chance to shoot it yet.

I may work up some subs that will cycle, but that isn't my main focus. I'll be shooting subs with the gas turned off more often than not.
I think you'll notice a difference with supers also, I did with the carbine gas. It will be interesting to hear what you think.
300 Blackout, not just for sub-sonics.

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John A.
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Re: Finally, the perfect (compromise) 300 BLK AR

Post by John A. » Fri Oct 25, 2019 8:03 am

I really enjoy discussions such as they and you're spot on with your assessment about barrel length and suppressor noise.

Longer barrels allow more time for powder burn and the gas cool down more compared to shorter barrels. Thus allowing the suppressor to be more efficient.

The drawback with longer barrels is increased velocity. So, you generally need to load a little lighter powder charge provided there is enough gas to cycle the bolt. Which too, decreases the sound and makes the suppressor more efficient.

In hindsight, due to those reasons, I wish that I had about an 11 inch barrel on my blk than the 8.5" While it works well, 3 more inches of dwell would seem ideal.

That's why I chose a 10.5" barrel on the 9x39 project and am shortening the gas port to 4.5" in length rather than the 6 inch pistol gas port placement so I can use more powders and experiment more to find something that both I, and the gun likes
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Re: Finally, the perfect (compromise) 300 BLK AR

Post by tallburnedmidget » Fri Oct 25, 2019 3:18 pm

Great post BBP!
I didn't my super short barrel (like 7.5" I think) due to lack of velocity for supers. I went up to a 10.5" and that was the sweet spot for best of both worlds with length and velocity for hunting.

I really like how you did a side charging and adjustable gas block to get super quite and hand cycle. Wish I would have thought of it hahaha. I have my bolt action with a 10 round mag so I at least have something in the ball park but it's not an all in 1 system like yours. Great work!

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Re: Finally, the perfect (compromise) 300 BLK AR

Post by bangbangping » Fri Oct 25, 2019 5:47 pm

tallburnedmidget wrote:
Fri Oct 25, 2019 3:18 pm
Great post BBP!
I didn't my super short barrel (like 7.5" I think) due to lack of velocity for supers. I went up to a 10.5" and that was the sweet spot for best of both worlds with length and velocity for hunting.

I really like how you did a side charging and adjustable gas block to get super quite and hand cycle. Wish I would have thought of it hahaha. I have my bolt action with a 10 round mag so I at least have something in the ball park but it's not an all in 1 system like yours. Great work!
Thanks. Everyone has their own idea of what works and what they need. I've been through a bunch of 300 BLK guns and/or barrels over the last six years or so, and can't imagine that this won't do everything I want. I'm also pretty sure I'll want to try something else in a few months. :lol:

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Re: Finally, the perfect (compromise) 300 BLK AR

Post by tallburnedmidget » Fri Oct 25, 2019 7:36 pm

bangbangping wrote:
Fri Oct 25, 2019 5:47 pm
tallburnedmidget wrote:
Fri Oct 25, 2019 3:18 pm
Great post BBP!
I didn't my super short barrel (like 7.5" I think) due to lack of velocity for supers. I went up to a 10.5" and that was the sweet spot for best of both worlds with length and velocity for hunting.

I really like how you did a side charging and adjustable gas block to get super quite and hand cycle. Wish I would have thought of it hahaha. I have my bolt action with a 10 round mag so I at least have something in the ball park but it's not an all in 1 system like yours. Great work!
Thanks. Everyone has their own idea of what works and what they need. I've been through a bunch of 300 BLK guns and/or barrels over the last six years or so, and can't imagine that this won't do everything I want. I'm also pretty sure I'll want to try something else in a few months. :lol:

Yeah I hear you on both accounts.
Cabelas or Bass Pro was running a $100 rebate on Savage Axis 6.5 Creedmoor rifles earlier this month putting them at like $229 before tax!
Those Savage Axis rilfes aren't anything much to look at but the 4 I have fired have been damn good shooters. I'm kind of kicking myself for not jumping on it now that my ol lady and my brothers girlfriend are now hunting. My ol lady is doing fantastic with my Savage Axis 300 BLK and has 7 whitetail kills with it over the past 2 years (I did the barrel swap on a .223 Axis to make the rifle). Having a 6.5 CM would be the perfect addition for a longer range rile she could shoot well with and have little recoil.

Maybe they'll have the sale again Black Friday/Cyber Monday weekend :)

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Re: Finally, the perfect (compromise) 300 BLK AR

Post by popper » Thu Oct 31, 2019 2:24 pm

I really like my 10" pistol, light weight truck/field gun. Working to get low fps 150gr supers like a PCC - non blowback. Gotta wait till temp is above freezing to try my loads. Pistol gas is good, shortening it more still leaves higher pressure at the port so I expect there would be more gas cutting (PB cast), had to cut the last GB off as it leaded to the barrel.
Shoots good with 150 BO GD @ 100. Same with vmax & SSTs. Thought about a side charger but removing the handle to lube the bolt or clean the bore is a PITA? Not sure why a handle like my berreta S.G. wouldn't work - piece of plastic that just pulls out.

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