Suppressing a 7.5" BBL AR Platform.

[BlindedByScience]

Suppressing short 5.56 firearms isn't trivial. The heat and pressure is serious. My 5.56 is 14.5" but the 300BO is the short one. Very different physics involved. Here's a very solid work on what happens with short 5.56. Worth consideration. I'd get a 300BO top for short suppressed work. One opinion...

Barrel Length Studies in 5.56mm NATO Weapons – Small Arms Defense Journal

www.sadefensejournal.com

 

[Zechariah]

Dead Air for me.
Dont hate me cuz I'm short.
Guy

View attachment 1039076

Oh I like dat!

 

[ScatPackLife]

Suppressing short 5.56 firearms isn't trivial. The heat and pressure is serious. My 5.56 is 14.5" but the 300BO is the short one. Very different physics involved. Here's a very solid work on what happens with short 5.56. Worth consideration. I'd get a 300BO top for short suppressed work. One opinion...

Barrel Length Studies in 5.56mm NATO Weapons – Small Arms Defense Journal

www.sadefensejournal.com

Great article. Still planning to get a suppressor for my AR Pistol as I think the OP should too.

Your take away, and the author's, is to not go shorter than 14.5".

My take away is that you just need to take extra precautions: be sure you use solid rifle components (quality barrel, bolt and GB at the least), use an adjustable gas block (a "blow off valve" style GB would be a good choice, that's what I have), and make sure your suppressor doesn't have barrel length restrictions. Most importantly, by a quality suppressor from a reputable brand and you should be fine. If there were excessive issues with 556, short barrels and suppressors we would be hearing about it more I think.

Also, according to his write up I should be having all kinds of issues with my 556 pistol, but I have shot several hundred rounds with zero malfunctions, even with cheap ammo. When I do suppress it I well do a short write up as to reliability and note any excessive wear on the gun.

(FYi, not instigating, just posting my opinion. I feel like too often people get upset when someone disagrees with them and that's often not necessary. People are entitled to there opinions and we are all entitled to disagree).

 

[Geardo]

have room for the 8" barrel since it's better than a 9mm.

Is it though? 22 magnum velocity, energy levels varely above 9mm, at a velocity that will cause most rifle ammo to not perform on target effectivly.

You might be better off with a PCC or 300blk.

 

[ScatPackLife]

Is it though? 22 magnum velocity, energy levels varely above 9mm, at a velocity that will cause most rifle ammo to not perform on target effectivly.

You might be better off with a PCC or 300blk.

I've seen enough ballistic stuff on you tube that I believe for a CQC tool the 556 Pistol will work just fine. Especially with the right ammo. Right now I load 62gr lead free Double Tap, it's good stuff. I plan to do some ballistic testing but haven't had time.

I do have a Scorpion EVO pistol (great gun BTW) but only one and I have multiple safes around the house.

Between 9mm PCC, short barrel 300 blk, and short barrel 556, they will all be effective and I don't see one being vastly superior over the others. I'm good with my 556 AR Pistol, thanks.

And a 556 from an 8" barrel is way more powerful than a 9mm. Use 55gr for example, quality ammo you would see around 2450fps=733ft lbs. 9mm is often around 350ft lbs. I'm gonna stick with what I have thanks.

 

[Geardo]

I've seen enough ballistic stuff on you tube that I believe for a CQC tool the 556 Pistol will work just fine. Especially with the right ammo. Right now I load 62gr lead free Double Tap, it's good stuff. I plan to do some ballistic testing but haven't had time.

I do have a Scorpion EVO pistol (great gun BTW) but only one and I have multiple safes around the house.

Between 9mm PCC, short barrel 300 blk, and short barrel 556, they will all be effective and I don't see one being vastly superior over the others. I'm good with my 556 AR Pistol, thanks.

And a 556 from an 8" barrel is way more powerful than a 9mm. Use 55gr for example, quality ammo you would see around 2450fps=733ft lbs. 9mm is often around 350ft lbs. I'm gonna stick with what I have thanks.

MAWP mawp mawp

 

[User 1234]

5.56/.223 ballistic test carbine vs SBR -

5.56/.223 ballistic test carbine vs SBR I have been working on a a few projects for Barnes Precision Machine, one of which was a ballistic test for a common barrel length for SBR and compare that to the AR-15 carbine 16″ barrel. Some history of the 5.56 to begin with. The 5.56x45mm NATO began...

rangehot.com

 

[wired]

Ive built several . They work fine suppressed. Much better than unsuppressed thats for sure. I built the suppressors. The manufacturers of said suppressors said it was OK. I listen to him.

Whenever anyone brings u the ballistics of a 7.5" 5.56 AR I always inquire what they are actually shooting at. Not what they dream about shooting at. Theyre never honest.

 

[User 1234]

I will never understand why some people make it a mission to rain on someone else's parade. If it isn't putting someone in grave danger, why try to talk someone out of their preference and into your same choices? It isn't only the firearms world. Cars, sporting goods, you name it. "That $hit is dumb!" Live and let live. Tyranny and controlling others is not the way of the freedom-minded gun owner.

 

[wired]

Great article. Still planning to get a suppressor for my AR Pistol as I think the OP should too.

Your take away, and the author's, is to not go shorter than 14.5".

My take away is that you just need to take extra precautions: be sure you use solid rifle components (quality barrel, bolt and GB at the least), use an adjustable gas block (a "blow off valve" style GB would be a good choice, that's what I have), and make sure your suppressor doesn't have barrel length restrictions. Most importantly, by a quality suppressor from a reputable brand and you should be fine. If there were excessive issues with 556, short barrels and suppressors we would be hearing about it more I think.

Also, according to his write up I should be having all kinds of issues with my 556 pistol, but I have shot several hundred rounds with zero malfunctions, even with cheap ammo. When I do suppress it I well do a short write up as to reliability and note any excessive wear on the gun.

(FYi, not instigating, just posting my opinion. I feel like too often people get upset when someone disagrees with them and that's often not necessary. People are entitled to there opinions and we are all entitled to disagree).

It is just amazing that Special Forces guys survived all those years with the 10.5" and 11.5" Colt Commandos. They werent serious operators. That is Fo Sho.


Pic of my 11.5" Colt Commando to stress what a non operator putz I am.

 

[BlindedByScience]

I will never understand why some people make it a mission to rain on someone else's parade. If it isn't putting someone in grave danger, why try to talk someone out of their preference and into your same choices? It isn't only the firearms world. Cars, sporting goods, you name it. "That $hit is dumb!" Live and let live. Tyranny and controlling others is not the way of the freedom-minded gun owner.

Got to say i don't know it all. I learn by reading, among other things. If some guy does a careful, well thought out study, I'll read it over and give it some thought. I didn't see anywhere in the article where he said it was dangerous...just that there were things to consider. Don't recall saying or reading "...that $hit is dumb..". Maybe not optimum for the round. Good to be aware of his measured pressures. Take the info into consideration, do what you choose. I found it interesting.

 

[Member 34319]

Whenever anyone brings u the ballistics of a 7.5" 5.56 AR I always inquire what they are actually shooting at. Not what they dream about shooting at. Theyre never honest.

Truth hurts!