[steveH]

Howdy I'm new to the board.

I don't have a 6.8 yet but I'm considering one now. I was drawn in by the new numbers that have been posted in the "State of the 6.8" threads being posted around the net, which somehow caught my attention. It caught me by surprise that the 6.8 is not much shy of a .260 now (only exaggerating a little), which is one of my favorite rounds, and in the smaller AR platform? Awesome...

One thing that's always bothered me a bit about my 16" AR (in 5.56) is that its got a lot of blast for such a mild cartridge, especially compared to my 22" bolt gun in .223. The blast puts my wife off a bit too when she shoots it. Otherwise we love the AR platform.

So my question - does the 6.8 have noticeably more blast than the 5.56 and would the 18" barrel help a bit? Weight is also an issue, don't want much more of that. Clear as mud?

Thanks for your attention,
Steve

 

[olemiss]

I have only fired hundreds of 6.8 SPC rounds as opposed to some on the forum who have fired thousands or tens of thousands. However, I have noticed that there is slightly less blast with a 16 inch 6.8 barrel compared to a 16 inch 223 barrel. One thing to keep in mind is that both cartridges use about the same amount of powder, but the bore of the 6.8 is .277 inches which is substantially larger than the .224 inches with the 223 Rem. This means that the pressure falls much more quickly in the 6.8 barrel making the exiting gas lower in pressure which would correspond to less muzzle blast. This also assumes similar muzzle devices on the two guns.

 

[constructor]

I have only fired hundreds of 6.8 SPC rounds as opposed to some on the forum who have fired thousands or tens of thousands. However, I have noticed that there is slightly less blast with a 16 inch 6.8 barrel compared to a 16 inch 223 barrel. One thing to keep in mind is that both cartridges use about the same amount of powder, but the bore of the 6.8 is .277 inches which is substantially larger than the .224 inches with the 223 Rem. This means that the pressure falls much more quickly in the 6.8 barrel making the exiting gas lower in pressure which would correspond to less muzzle blast. This also assumes similar muzzle devices on the two guns.

Agree, just stay away from the brakes

 

[Boomshack]

Agree, just stay away from the brakes

What do you suggest? I was thinking going with the PWS FSC 30.

 

[NE-AR]

Howdy I'm new to the board.

One thing that's always bothered me a bit about my 16" AR (in 5.56) is that its got a lot of blast for such a mild cartridge, especially compared to my 22" bolt gun in .223. The blast puts my wife off a bit too when she shoots it. Otherwise we love the AR platform.

So my question - does the 6.8 have noticeably more blast than the 5.56 and would the 18" barrel help a bit? Weight is also an issue, don't want much more of that. Clear as mud?

Thanks for your attention,
Steve

Just curious, are you shooting with or without ear protection?

 

[constructor]

All brakes are loud if you ever shoot without protection like when hunting, some hunt with electronic protection and brakes would be ok if that is the case. If you plan to hunt without hearing protection I would stick to an A2 or DPMS Panther f lash hider.

 

[rushca01]

Howdy I'm new to the board.

I don't have a 6.8 yet but I'm considering one now. I was drawn in by the new numbers that have been posted in the "State of the 6.8" threads being posted around the net, which somehow caught my attention. It caught me by surprise that the 6.8 is not much shy of a .260 now (only exaggerating a little), which is one of my favorite rounds, and in the smaller AR platform? Awesome...

One thing that's always bothered me a bit about my 16" AR (in 5.56) is that its got a lot of blast for such a mild cartridge, especially compared to my 22" bolt gun in .223. The blast puts my wife off a bit too when she shoots it. Otherwise we love the AR platform.

So my question - does the 6.8 have noticeably more blast than the 5.56 and would the 18" barrel help a bit? Weight is also an issue, don't want much more of that. Clear as mud?

Thanks for your attention,
Steve

What kind of muzzle device do you have on your AR's now? If muzzle breaks, that would be a big reason. My dad has a plain jane Colt 6400 and it has a muzzle break on it, all of mine have flash suppressors and there is a HUGE difference when shooting between the two. When I shoot his I get the big blast in my face and it really pounds my head, when I shoot mine it's much more pleasent. It's also amazing how much loader the 6400 is since it directs all the gas to sides!

 

[rcrandall]

Like the other guys have said, the 6.8 seems to have less "crack" and more "boom". I have an 8.5" 6.8 with A2 flash hider and the muzzle blast isn't bad at all....well, not to the shooter. I've been told there is a little concussion to those standing to the sides. The 6.8 is truly a pleasure to shoot in all barrel lengths, I have the 8.5", 14.7", 16", and 18".

 

[steveH]

Just curious, are you shooting with or without ear protection?

NE - We're always with ear protection when practicing which is all I've done with the AR so far. The blast isn't bad and it's something I'll get used to. I think starting with the 22" .223 did it to me, it does make a bit of difference. I think I'm getting used to it, I do love to shoot the AR (it's my first autoloader).

rushca - I don't have a brake, just the standard LMT flash hider. Not sure if the flash hider has any noticeable brake affect, my bolt gun has none as per usual.

olemiss - interesting, didn't know the larger caliber could help, thanks for the info.

 

[steveH]

flash hiders

Also, maybe a dumb question, but what would I lose by going without a flash hider and gaining a little handiness that way (or looked at another way, replacing it with a little more barrel)?

The gun would be used for shooting rocks, mostly, sometimes hogs or coyotes if I can find them (usually not, but it's fun trying...)

 

[olemiss]

I have a Smith Vortex on my 6.8 and 5.56 and really like them. I would never shoot an unsuppressed gun without hearing protection anymore. Several years ago, I was hunting and shot a deer with my 300 Win Mag without hearing protection, and swore I would never do that again. Each time, hearing suffers and never recovers. I would rather be able to hear when I am old than be inconvenienced with putting hearing protection on during a hunt.

 

[Clint]

Also, maybe a dumb question, but what would I lose by going without a flash hider and gaining a little handiness that way (or looked at another way, replacing it with a little more barrel)?

The gun would be used for shooting rocks, mostly, sometimes hogs or coyotes if I can find them (usually not, but it's fun trying...)

Welcome Steve,
in general the 6.8 is optimized for short barrels and it uses faster powders than 556.

You don't gain much velocity by going from 16" to 18", especially in the lighter loads.
The faster powder is the main reason the pressure drops more quickly.
This drop in pressure tends to reduce blast.

 

[ArtFWTx]

Also, maybe a dumb question, but what would I lose by going without a flash hider and gaining a little handiness that way (or looked at another way, replacing it with a little more barrel)?

The gun would be used for shooting rocks, mostly, sometimes hogs or coyotes if I can find them (usually not, but it's fun trying...)

That would be like the AR's sold during the Assault Weapon Ban! You do see some longer barreled varmint and target guns with plain muzzles. Get the muzzle device, you know you want one. Seriously though there is a benefit to a flash suppressor if you're using some ammo with a powder that has a noticeable flash. My bare muzzled Mini 14 made a beach ball sized blast with cheap ammo in bright sunshine. A flash suppressor would have tamed that a bunch.

You're doing a good job by asking and reading up on muzzle devices. With muzzle brakes directing gases to the side to stabilize the barrel and recoil impulse, they do tend to be very noisy, especially to your shooting partner beside you. That's the trade off for having a muzzle brake.

I would go with the straight up A2 flash suppressor. It's proven, and inexpensive. My next choice would be the Vortex flash suppressor. It costs a little more, but works amazingly well, and looks cool too.

Or.... you could go through the ATF paperwork, pay the tax, and buy your rifle a real silencer. There you go. We have a forum for silencers also.

 

[marinesg1012]

I agree the A2 is the way to go i have a brake on my 20 inch and it is fine just make sure the barrel is outside if your shooting it out of the bed of your truck or a blind.... the truck one about blew my ears, and I had ear pro on

 

[airdj10]

Seeing that it's a combo brake/flash supressor where does the FSC30 fit on the blast scale?
Of course it's all subjective but for comparison's sake, if a pure flash supressor is a 1 and a pure brake would be a 10...would the FSC30 be a 5? Or does it have just as much blast/volume as any other brake.

 

[paulosantos]

The FSC30 is the least abnoxoous muzzle brake, but it is still a muzzle brake. Stick with a flash hide if possible.

 

[Bushman_269]

The FSC30 is the least abnoxoous muzzle brake, but it is still a muzzle brake. Stick with a flash hide if possible.

The gun club where I do my bench shooting has an enclosed range building with roll up garage doors for the shooting stations. I noticed huge difference when shooting my 6.8 (16" Kotonics barrel) between the FSC30 brake and the Phantom FH. The brake was considerably louder both for the shooter and bystanders behind and to the side of the shooter. The FSC30 does a good job of flash suppression and recoil reduction but the increased blast was a deal breaker for me. I am anxious to try the Vortex on the 6.8, it is my favorite FH on my 5.56 ARs.

 

[fireguy]

Agreed, you may not convert many shooters over to the 6.8 if they can't get close enough to you to ask you what you're shooting

I hear you guys about the virtues of ear protection. My lapse of thinking in that regard came when I shot at a deer from inside an enclosed stand with my 7mm Rem Mag, no hearing protection. Stupid me, I wasn't careful to make sure the muzzle was well outside the stand. When it gets really quiet I think I can still hear the ringing in my ears, a decade later...

 

[joshuades]

The gun club where I do my bench shooting has an enclosed range building with roll up garage doors for the shooting stations. I noticed huge difference when shooting my 6.8 (16" Kotonics barrel) between the FSC30 brake and the Phantom FH. The brake was considerably louder both for the shooter and bystanders behind and to the side of the shooter. The FSC30 does a good job of flash suppression and recoil reduction but the increased blast was a deal breaker for me. I am anxious to try the Vortex on the 6.8, it is my favorite FH on my 5.56 ARs.

Got one on mine. I like it a lot (almost night blind, so any flash at night is painful), but it is the model for the 7.62 (5/8x24tpi) and is a whole ounce heavier than the one for 5.56. At the end of an 18" barrel, it's a noticable difference. I want to get one for the 5.56 and see if I can ream it and tap it to my threads since it's a bit smaller and lighter.

 

[NE-AR]

I am one of those older guys who shot for years without hearing protection or used it "sometimes" and now I have a constant ringing in my ears. I wear hearing protection 100% of the time on the range and 90% of the time while hunting.

Please, either use hearing protection or buy a suppressor (I wish I could but I have to save money for a 6.8).

As for the plain barrel vs FH or break, I'm not a big fan of brakes unless the rifle generates massive recoil or you are shooting varmint colonies where you'd like to see your bullet hit. I like the A2…plus it provides a some protection for the crown of the barrel.