7.3 inch upper with suppressor questions

[fox.josh]

Gentlemen,

My name is Josh and while new to this site I am not new to guns. Alittle about myself: I am an ex Army Sniper with two Iraq combat tours. I am now a contractor were I am a DDM for in Afghanistan. As so I do mostly long range large caliber shooting. I am not new to suppressors either as I have used them in military and contracting on my sniper rifles. Being said I recently purchased a 7.3 inch CMMG M7 upper with plans to add a suppressor. After some searching and coming up with little information, I read that with that short of barrel people are having problems running suppressors ie: voiding warranty and corrosion. Any information would greatly be appreciated on this subject. With that being said i know a 10 inch or longer upper is more ideal but this is what i wanted. And also what company is making the absolute quietest can. Not really worried about price just want it quiet. Also if anyone has experience with these size barrels please chime in with information on making it run correctly ie: what style buffer spring etc. to run. thanks alot guys and appreciate the information in advance.

[silencertalk]

AAC's 762-SDN-6 is ok on that. It is a 308 can.

[fox.josh]

thanks alot for the information. Not to question your expertise. But could you explain why a 308 caliber would be best. Like i said i believe you and that would be awesome as I am about to purchase a 308 can as well. Just any information on possible sound reduction and performance I might get out of the 308 can. Thanks

[fox.josh]

also with that can what options do i have as far as flash suppressors for mounting?

[JasonAAC]

thanks alot for the information. Not to question your expertise. But could you explain why a 308 caliber would be best. Like i said i believe you and that would be awesome as I am about to purchase a 308 can as well. Just any information on possible sound reduction and performance I might get out of the 308 can. Thanks

The reason a 30 cal can is better in this application is that the bigger bore gives you a little more protection from baffle strikes in the event of an unstable bullet. Also, the larger bore allows some of the gas and unburnt powder past the blast baffle where it is 'caught' by the additional baffles rather than the blast baffle taking the brunt.

For mounting options, you have your pic of any 51-tooth ratchet mount:

The BLACKOUT flash hider: http://www.advanced-armament.com/product.aspx?pid=509

The BLACKOUT Muzzle Brake: http://www.advanced-armament.com/product.aspx?pid=728

The BRAKEOUT Comp: http://www.advanced-armament.com/product.aspx?pid=682

The flat surfaces in the brake and the BRAKEOUT will absorb some of the damage before the gas/powder hits the can's baffle stack.

I am not sure of the rifling twist on that upper, but you'd want it to be 1:7" in order to have the best chance of stabilizing the bullets.

Keep in mind that with 5.56 and a barrel that short, not matter what can is on it, you'll see accelerated wear inside the can and it'll be loud.

[JasonAAC]

To add, using the 762-SDN-6 (308) on a 5.56 gun will be approx. 3-4 dB louder than using the dedicated 5.56 can (the M4-2000).

It also is about 2 ounces heavier and one inch longer, but you get the benefit of getting one can for multiple hosts.

[fox.josh]

thanks guys for the information. i knew the 7.3 inch is gonna be loud even suppressed but will i be safe without hearing protection? and yes it is a 1 in7 twist. thanks

[Eight]

With full-power .223 or 5.56, no, it will not be hearing safe.

[fox.josh]

which brands of subsonic ammo are you guys getting good results from?

[JasonAAC]

It will most likely not be hearing safe.

Subsonic .223 is generally terrible and will not have much downrange effect or cycle your gun- especially in a 7.3 where there is very little dwell time to begin with.

[withoutremorse42]

best option, go up to 11.5 inches or longer and watch the noise drop, the suppressor live longer and give a wider selection of bullets stabilized.

[rob_s]

There reaches a point where you are just asking too much from the platform/caliber combination.

Expecting hearing safe out of a 7.3" barrel with 5.56 that will also cycle the gun and have good terminal effect downrange is one of those points. This type of need, however, is exactly the driving force behind calibers like the 300 BLK.

[Libertarian_Geek]

Requirements: AR 15 platform. A small caliber. A 7.3" barrel. It must cycle. It must be quiet. Cost isn't an issue.
Solution: a short .22LR dedicated upper with a good rimfire can. If can cost isn't an issue, then the cost of a new upper won't be either.

If you're willing to have piss poor velocity, then you may as well go rimfire.