Suppressed and Duty 5.56 Rounds

Didn't find this with a search. I am looking for a good round for use in a 1/7 twist 16 inch overall mid length BCM, suppressor is a Griffin Armament M4SD II. I am looking for both work rounds and hunting/ long range rounds.

Hunting/ Long range:
I'm looking for something quiet with good accuracy out to 200 if possible while still able to take out small to medium sized game (pest control, you know coyotes, hogs, humans etc.)

The biggest thing is I am wanting to find a round that will get me as quiet as possible while still reliably cycling and humanely taking down any hogs/ 'yotes I'm shooting.

I am also looking for a round that will work good out to 600 maybe more.

Work Use:
My requirements here are for good penetration on vehicles, solid reliability in both cycling and accuracy (average engagement ranges in my AO can be between 50-200 depending on area of the county I am in. Some of our farms can get out to 500-600 meters also my rifle stays suppressed the majority of the time because i'm about the only one in my department that carries eye and ear pro in the front seat with them and I may not have time to grab it if needed. I'm not expecting to walk away from any UoF unscathed, you have to deserve victory, but if I can get a good round that when used in conjunction with my can will limit hearing damage (for both me and my bros/ sisters) a little more then the others while inside a vehicle or building it may be worth the investment.

Any recommendation, would appreciate any good relevant data on what ever round you recommend.


Regular Member
How are you defining quiet? I don't know of any of the good 5.56 duty loads that are subsonic, especially ones that will push out to 500m.
Ok I wrote this early this morning before work while I was in a rush and had not had my coffee yet.

Let me clarify, I am not looking for 1 round that will do all of this but a couple different types of ammo for different purposes, also I am not expecting to use the duty round for hunting or vice versa. Right now I carry PMC and M855 with my reasoning being the PMC is for general purpose and if I know i'm gonna be shooting from or into a vehicle I have green tips available (PMC was chosen because it is readily available around here and I have a ton of it being that I use it for training ammo M855 for the same reason, I have a ton of it.). Let me change up something on the requirement for the duty round. Average engagement distance from contact range to 50-75 yards with a max of 200 yards, 500 yards just won't be realistic for a patrol rifle and with the terrain around here I can maneuver in closer. I would like to have one type of ammo that will work for those distances while keeping quiet enough with the can to prevent or limit hearing damage. On the flip side, I want another round that can punch through metal if I need to engage a vehicle.

For hunting and distance shooting, I'm wanting one round that is good for hunting hogs and coyotes and such but quiet enough to not really bother the neighbors 200 yards max range. Then one round that is good for distance (think competition or just having fun at distance with my bros) around 500-600 yards max.

On using .30 cal, I would love a 308 or 300 BLK, but I would be the only one using one and the ability to grab extra mags from anyone else's bag or car just seems more appealing then being limited to just my stash.


Regular Member
Are you going to have different sights for each of those rounds? [sarcasm] There are no magic rounds for this or that that you can just swap out for various purposes. Again, you're asking for too much.
Doc, that info was out before the 75gr gold dot. Are those considered gtg?

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I won't speak for Dr Roberts, but I will post a quote from him on another forum regarding this, as compared to the 55/62 and 64gr versions, regarding his impression of what the 75gr will offer:
Superior long range performance, better intermediate barrier capability--particularly auto glass, closer trajectory to other 70+ gr ammo.
I believe he has tested this round, but his data has not been made public, nor has he commented on it.

ATK, however, has made their data public, so I can share a bit of it. The round is performing very similarly to the 62gr stuff, except it penetrates a couple of inches more.

Regarding accuracy, I am shooting 1.5-1.8 MOA with it, 10 shot groups, 4x scope, government profile CHF/CL barrel, benched at 100 yards.

Regarding terminal performance, everything I have heard indicates that it is killing both bad guys and deer with authority.

Regarding long range potential, the ballistic coefficient is in the mid 3's. ATK is misrepresenting it as 0.4 on their website, but a call to their ballisticians revealed internal testing shows 0.373. I chronographed some at 100 yards, and at 3 yards, and regressed velocities and ended up with identical loss percentages as 77gr SMK, which corroborates ATK's .373 claim.

Expansion I have seen in gel testing has been as aggressive as >0.7", and penetration as much as >19", depending on barrel length, in bare/clothed gel tests.

In short, I really like this round. It will perform accurately out to 600 yards, and terminally out to 250-300 at least, from a 16" barrel.

It should meet most of your criteria, as on all FBI protocol tests, it averages well over 12" of penetration.