.300 BLK - Does Barrel Profile Matter for Suppressed Use?

[etrain16]

With a suppressor on the way, I'm very interested in adding a .300 BLK upper to shoot subsonic rounds with that suppressor. I've been doing some reading/research and I'm seeing that approximately 10" barrel length is the optimum for .300 BLK, though it can work fine down to about 8". But my real question is on the barrel profile. Some are saying and HBAR/Heavy barrel profile is the only way to go if shooting suppressed - primarily because the barrel will heat up more with a suppressor and the heavy profile will help to dissipate that heat. Others are saying the lighter weight A2 profile barrels are just fine. I'm finding a variety of options out there and I'm just curious if any of you have some more practical advice/thoughts on this? Is barrel over-heating with a suppressor more of an issue with a lighter profile barrel?

This would ultimately be planned to mate to a future SBR lower. For now, it would reside on a pistol lower.

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[Twodogs]

I'm running an 8" barrel on mine I don't think profile makes much difference at that length.

 

[HB of CJ]

Probably no difference. Be sure to talk to your can maker. They will be able to prep your AR15 for suppressor use.

All Oregon State Laws, US Code Laws, NFA Laws And BATFE Rules Apply.

www.eliteiron.com

 

[etrain16]

Probably no difference. Be sure to talk to your can maker. They will be able to prep your AR15 for suppressor use.

All Oregon State Laws, US Code Laws, NFA Laws And BATFE Rules Apply.

www.eliteiron.com

The suppressor I have on the way is the Silencerco Hybrid - not sure any prepping is required on this one, just a thread adapter for the barrel.

 

[Twodogs]

I needed a adjustable gas block and a reduced power spring to make mine run with sub loads.

 

[etrain16]

I needed a adjustable gas block and a reduced power spring to make mine run with sub loads.

Did you build your upper, or buy it assembled?

 

[Twodogs]

Did you build your upper, or buy it assembled?

I built it. I'm running a Dead air sandman-s suppressor but I do have a Hybrid.

 

[etrain16]

I built it. I'm running a Dead air sandman-s suppressor but I do have a Hybrid.

I'm planning to buy an already assembled upper. I don't know from whom yet, but I'm hopeful whatever I get won't have an issue running subsonic loads or suppressed.

 

[v0lcom13sn0w]

i run a med profile 10" ballistic advantage barrel.

 

[Member 34319]

I think a heavy barrel might help, you might end up dumping mags quicker since it's quiet and enjoyable.

As for 300blk...

I've owned a single shot 300 black, I regret selling now as I have a 9mm can on its way some time soon that I could have used with it.

Now, I too think about adding a 300 back to the mix, but I can't say I really really want to.

I like the idea of a bolt gun, but I've witnessed "subsonic loads" go supersonic in longer barrels. Not sure if that matters, but the silencer I have coming states subsonic only.

 

[wired]

With a short barrel like 7-8" it doesnt really matter. The longer the barrel the heavier you want it. That silencer is pretty heavy and you'll see stringing with a long thin barrel. Ive got 4 300 BO uppers in pistol and SBR format with no longer than 8" and theyre all heavy barrel. If someone made a 5-6" that wasnt overpriced I'd on it like a hobo on a hotdog.

My favorite run everything and hit stuff barrel is a 7.5" Anderson I paid $45 for.

 

[ConcernedCitizen]

Shoulder profile matters more than barrel profile.

Here's the barrel I'm currently using:

The problem is that the narrow shoulder is not wide enough for the flash hider to square up against, so my suppressor is out of alignment with the bore. I tried using a muzzle shoulder ring to fix it, with no luck.

I now have a SCAR 17 flash hider mount on the way, which is designed to square up against the muzzle, not the shoulder. If this doesn't work, I'll be looking at replacing the barrel.

Some manufacturers, like Ballistic Advantage and Faxon, often flare the barrel diameter back up at the shoulder. If I purchase a new barrel, I think the Ballistic Advantage Hanson Profile is what I would choose.


I hope this helps!

 

[etrain16]

Shoulder profile matters more than barrel profile.

Here's the barrel I'm currently using:
View attachment 475825
The problem is that the narrow shoulder is not wide enough for the flash hider to square up against, so my suppressor is out of alignment with the bore. I tried using a muzzle shoulder ring to fix it, with no luck.

I now have a SCAR 17 flash hider mount on the way, which is designed to square up against the muzzle, not the shoulder. If this doesn't work, I'll be looking at replacing the barrel.

Some manufacturers, like Ballistic Advantage and Faxon, often flare the barrel diameter back up at the shoulder. If I purchase a new barrel, I think the Ballistic Advantage Hanson Profile is what I would choose.
View attachment 475824

I hope this helps!

It does help, but more for a question I didn't even know I had. I hadn't really thought about that shoulder profile before. I'll be keeping an eye on that now.

 

[v0lcom13sn0w]

It does help, but more for a question I didn't even know I had. I hadn't really thought about that shoulder profile before. I'll be keeping an eye on that now.

ive never even looked at my 300blk shoulder before. i just looked thru the upper into the barrel thru the suppressor and saw daylight. my can is a 46 cal can so even if it was just a micron out of square it wouldnt matter.

 

[ConcernedCitizen]

ive never even looked at my 300blk shoulder before. i just looked thru the upper into the barrel thru the suppressor and saw daylight. my can is a 46 cal can so even if it was just a micron out of square it wouldnt matter.

Here's how far off center mine is:


It doesn't touch the end cap, but it's far too close for comfort.

 

[v0lcom13sn0w]

10" .300 Blackout Pistol Length CMV AR 15 Barrel | AR Replacement Parts


my barrel

 

[v0lcom13sn0w]

Here's how far off center mine is:
View attachment 475876

It doesn't touch the end cap, but it's far too close for comfort.

dang dude that is off a bit.

 

[Mygrainman]

I run A Balistics Advantage Hansen 8.3" in mine.. has eaten up everything I've put into it without a single hiccup... Subs, Supers, Can no Can... it's been perfect and accurate. I don't think profile is as important as quality bore, rifling, proper gassing etc.

I also have a Hybrid46.

 

[Mygrainman]

Here's how far off center mine is:
View attachment 475876

It doesn't touch the end cap, but it's far too close for comfort.

 

[ConcernedCitizen]

That's why I invested in some drill rod to check bore alignment...

My new flash hider should be here in a few days, and we'll see if that fixes the alignment issue. If not, I'll be shopping for a new barrel.