300BLK SBR Setup and Q re: muzzle device

[JediGuy]

Edits below (after original post with muzzle device question) as upper is accessorized and tested with different lower setups.

Original post:

OK, I need to pick a Keymo muzzle device for a 300 BLK upper. This is a 7” barrel, so a little shorter than optimum, so I assume there will be some unburnt powder to blast the interior of a suppressor.

I wanted to focus this on “small,” assuming suppressed if using indoors for HD. KeyMicro brake seems like the easy option, it’s small and should (?) provide a small sacrificial baffle effect. This would be the only brake I have any more, as flash hiders just seem like a better idea all around, particularly with short barrels. Length/weight (size) and protection of suppressor are what I had prioritized.

However, KeyMicro brakes seem out of stock most places, so I figured I’d get general opinions.


Dead Air standard brake
*I thought about cutting the third baffle off this, seems like that would end up as a decent compromise.

Dead Air standard flash hider
*General good option, but lose any protection of suppressor while gaining flash diffusion. I’m not opposed to this, unless it would cause more wear than a brake, and I think it would.

SOLGW NOX
*Not considering. Extra size, and I’ve repeatedly read that it pushes down more than needed. No protection benefits at a higher cost than a standard Dead Air option.

Lantac
https://www.lantac-usa.com/product-p...-brake7-62-308
*Expensive. It almost looks like it has a flash hider after the brakes… Anyone have experience?

FCD 6310KM
https://www.forwardcontrolsdesign.co...x24_p_192.html
*I have one or two of these on hand. Comps a bit, good flash suppression. Does it protect the suppressor at all, or at least compared to a standard Dead Air flash hider?

Experience, other options?


Update on setup, still haven’t changed the muzzle device. 7/16/2022

Factory BCM 7” 300BLK barrel with 5” MCMR
Holosun 509T on Reptilia 1.93
Surefire X300U-B
Radian Raptor
BCM foregrip

Before adding the extras, I got one measurement with a pistol lower. I then got more with an SBR’d A5 lower. Note that the A5 with B5 Bravo is notably “longer” due to not closing











Weight with upper set up per above plus SBR A5: 6lb 4.2oz



Length with fully collapsed SBA3 on standard carbine receiver extension




Comments:
The difference in length between A5/B5 Bravo and standard/SBA3 is irrelevant to me, as the A5 position two is “right.” The SBA3 pulled out a bit ends up the same. So I lose some compactness for storage, but not much. In use, both are good.
Weight is well balanced, which may change with a suppressor.
As light as it is, I intentionally placed the 509T further to the rear than usual to shift the balance point. With the 1.93 mount, it works better than I expected; picking up the dot is super easy. I actually left the Eotech style circle dot on, as it seems to work well for me.


Next steps will be changing to Keymo muzzle device to go with a Rex Silentium MG7K .308 suppressor, recently arrived at my local FFL. I’m going to play around with the foregrip. I’m thinking I will keep it, as it feels “right” and also lines up well to activate the light.
I have a couple options for a different charging handle (Badger, Raptor SD, Q Raptor SL), but not moving anything around until I see how it works as is with the MG7K.

[themonk]

How often do you plan on running it suppressed?

[themonk]

I would do a KeyMicro Flash Hider - https://deadairsilencers.com/product/micro-flash-hider/

[1168]

What can? Also, there’s a 1210km and the JMac devices.

[gunnerblue]

Which suppressor and what kind of ammo? Handloaded or factory, supersonic or subsonic?

[JediGuy]

I don’t have the can yet, but probably a Nomad-30 or Nomad-Ti.

I did see the 1210KM going back through the FCD site. Not sure if it has a benefit over the 6310K, though.

As far as ammo… I plan to use both sub and super, but no way I’ll handload, at least not in the next several years.

[1168]

I don’t have the can yet, but probably a Nomad-30 or Nomad-Ti.

I did see the 1210KM going back through the FCD site. Not sure if it has a benefit over the 6310K, though.

As far as ammo… I plan to use both sub and super, but no way I’ll handload, at least not in the next several years.

Only benefit to the brake would be to protect your can. Probably fine, though, assuming the Nomad is rated for it. FWIW, a 7” 300 has the same volume to expand inside the barrel as an 11.5” 5.56. I’m sure it doesn’t work exactly like that, I’m just saying that if Dead Air allows it, I’d do it and not worry too much.

Edit: I’d get the can first before the gun.

[mike_f]

I have an 8" 300BLK barrel and run a Dead Air flash hider. I don't think there's enough erosive effect from 300BLK for me to worry about a sacrificial baffle. If it was an 8" 5.56 or .308 that I shot high volume suppressed I would look at it differently.

I have to shoot at a public range and I really dislike shooting near folks with short rifle barrels and muzzle brakes.

[JediGuy]

OK, I just grabbed a Rex Silentium MG7K 7.62, as $381 shipped is way better than I can pass up. Even if I go with something quieter for the 300 BLK later on, this can fill a desire for an option to put on 12.5 and longer 5.56 barrels.

Based on input, and since I can’t find the KeyMicro flash hider in stock, I’ll probably use the FCD 3610KM that I have on hand.

[1168]

OK, I just grabbed a Rex Silentium MG7K 7.62, as $381 shipped is way better than I can pass up. Even if I go with something quieter for the 300 BLK later on, this can fill a desire for an option to put on 12.5 and longer 5.56 barrels.

Based on input, and since I can’t find the KeyMicro flash hider in stock, I’ll probably use the FCD 3610KM that I have on hand.

You’re going to love that can. It will likely exceed your expectations.