Suppression on an AR15

mluning

mluning

Sergeant
Full Member
Minuteman
Aug 4, 2007
208
2
Houston Texas USA
#1
For those of you who have been there and done that can someone explain to me, or point me in the right direction, about barrel length, barrel profile, and length of the gas system, with use of a suppressor. What works best?

I'm looking to build a new AR15 around the use of a suppressor and I would like to get this one right the first time. I'm looking at either a 14.5" or 16" on this one and would like to keep weight at a minimum. If I choose to go with a lightweight profile should I expect a huge change in POI?

I appreciate your help on this one guys.

Mike
 
#3
Re: Suppression on an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: OBXLongRange</div><div class="ubbcode-body">.223 subsonics won't cycle in an AR. </div></div> he didn't really say anything about using subs. I find it odd how many people think it to be pointless to run high velocity ammo with a suppressor.
We all know subs sound better, but everything has its place, including full power with a can.
 
#4
Re: Suppression on an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: c_bass16</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: OBXLongRange</div><div class="ubbcode-body">.223 subsonics won't cycle in an AR. </div></div> he didn't really say anything about using subs. I find it odd how many people think it to be pointless to run high velocity ammo with a suppressor.
We all know subs sound better, but everything has its place, including full power with a can.
</div></div>

True he didn't. It's not pointless to run a can without subs but you aren't using the full potential. To me subs are useless ballistic wise but are a lot of fun to shoot.
 
#5
Re: Suppression on an AR15

First off, what is the rifle primarily going to be used for? I have a Smith & Wesson M&P15T that wears a 16" government profile barrel and a carbine length gas system with an AAC M4 2000 Mod 08 on the muzzle. Zero at 100 yards drops 4" strait down when I put the suppressor on, which is repeatable.

Generally speaking, mid length gas systems are easier on the rifle because of the lower pressure and longer dwell times. Also the shorter and fatter the barrel the less POI shift you will have, again generally speaking.

If you aren't going to SBR it then I would get a 16" barrel instead of the 14.5" with a pinned FH or break. There simply isn't enough of a difference between the two and I like to be able to remove my muzzle device if I ever have to.

I would build a rifle for an intended purpose such as home protection, SHTF, range toy, duty weapon, etc. Once that's done then I add the can and shoot the rifle to measure the POI shift. As long as the POI shift is repeatable I don't worry too much about it.

For more in depth information I would check out M4carbine.net or some of the other dedicated AR-15 forums.
 
#7
Re: Suppression on an AR15

I have a 20" AR-15 with a quicksilver titanium suppressor. Put an adjustable gas block on it so I could reduce the amount of gas when suppressed. Reality is a bit different than what I thought:
1. Love the suppressor. It is so much fun to shoot suppressed...psst...psst..psst. Just a soft, quiet sound. The adjustable gas block turned out to be pretty useless. I played around with it, but in the end just leave the gas turned full on. There is more carbon fouling in the action area, but it's just not that big a deal. I've shot hundreds of rounds at at time without any malfunctions. I'm going to put my non-adjustable gas block back on because it is simpler.
2. Adjustable gas block: get one if you want but it's not needed....see 1. above.
3. Titanium: rocks. It is less than half the weight of steel and cools very quickly.
4. Rifle-length gas system: rocks. After playing around with 16" barrels, all my ARs now have 20" barrels. They are quieter, they are cleaner, they are more reliable. What's not to like? If you aren't breaking doors down, who gives a shit about a shorter barrel?
 
#8
Re: Suppression on an AR15

Yes....beecause I can. 0.01% of us on here need to, the rest, well its fun, less muzzle blast, quieter, etc.

Your call, but any lenght 14.5-20 is all going to be about the same; the shorter end of that range might take some tweaking.

ZY
 
#9
Re: Suppression on an AR15

It would mainly be used as a ranch/brush gun. I don't plan on shooting it past 300-400 yards. I would prefer to keep the gun as small and lightweight as possible without sacrificing performance. I plan on using 75-77 gr bullets.

I'm too impatient to register it as a SBR and would prefer not to pin a 14.5" so would a 16" lightweight middy be a bad choice?

I'm looking at the AAC M4-2000.

And is it really worth droping almost $200 on a switchblock?
 
#11
Re: Suppression on an AR15

I run a Yankee Hill can on my 11.5 inch upper. It still gives me compact size, but will be fairly quiet. Accuracy stays good out to 300 yards. I have run a can on a HK 53, and it functioned fine even though the barrel is only 8.5 inch.
 
#12
Re: Suppression on an AR15

Look very closely at the design specs for the SPR mk12 (both the mod0 and mod1). These use an 18" match grade 1/7 twist SS barrel (SPR profile) with the Ops Inc 12th model suppressor (generally regarded as one of, if not THE quietest 22 cal cans). Building one of these as a true clone would be expensive, but if you only stuck with the barrel and suppressor, and used similar but cheeper parts for the rest of the project, you could save a few dollars.

These tend to be very accurate AR15s, and would be GREAT for 300-400yds. POI shift with the Ops Inc 12th model is almost nil. I believe it is also cheaper than the AAC as well, but that depends on if you can find a deal on one.
 
#13
Re: Suppression on an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: stungib</div><div class="ubbcode-body">

I'm looking at the AAC M4-2000.

And is it really worth droping almost $200 on a switchblock?</div></div>

Probably not. My latest build is based around an 18 inch Noveske barrel and switchblock. It might just be that I am using a .308 suppressor or the way that it vents the gas around the quickmount, but I cannot utilize any setting on the switchblock other than fully open. If I turn it to the suppressed setting the only rounds that will cycle are 55 grain XM193s. 77 grain MK262 and 62 grain M855 will not cycle reliably. I do have an Ops In 16th model on order so maybe that will make a difference.

I would also do some more research on the your suppressor. Some people are experiencing problems with the tooth mounts locking up tight; others are having great results. It sounds like it could be hit or miss.
 
#14
Re: Suppression on an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: stungib</div><div class="ubbcode-body">I'm too impatient to register it as a SBR and would prefer not to pin a 14.5" so would a 16" lightweight middy be a bad choice?

I'm looking at the AAC M4-2000.

And is it really worth droping almost $200 on a switchblock? </div></div>

I run an AAC M4-2000 on a 20" precision rig, a 16" BCM middy and a 10.5" SBR. I recently installed a switchblock on the 20" AR. Without the switchblock it ran fine but was definitely over gassed running with a standard rifle buffer. So far I like the switchblock. Was if absolutely necessary....No. Does the riffle run better with it....Yes.

On the 16" middy I run an H buffer and on the 10.5" I run an H3 buffer. They both run fine suppressed and unsuppressed. But honestly I rarely run the SBR unsuppressed. I use the muzzle break mount on the SBR (to help protect the can) and it is really unbearable to shoot unsuppressed. Personally I don't see the need to run a switchblock on my 16" middy.
 
#15
Re: Suppression on an AR15

Get a 16 inch barrel unless you want a SBR, suppressors are a plus.
Picture127.jpg
 
#16
Re: Suppression on an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Silentbushmaster</div><div class="ubbcode-body">Get a 16 inch barrel unless you want a SBR, suppressors are a plus.
Picture127.jpg
</div></div>

Huh?
 
#17
Re: Suppression on an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KYS338</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Silentbushmaster</div><div class="ubbcode-body">Get a 16 inch barrel unless you want a SBR, suppressors are a plus.
Picture127.jpg
</div></div>

Huh? </div></div>
It doesn't have to make sense, he was post bumping to sell. I can't wait to see him leave after ignoring the rules.
 
#18
Re: Suppression on an AR15

yup, his time is short here on the hide. just read his 20 other worthless comments in the semi forum on threads he has no clue about. oh and don't forget the suppressor section too...
wish i had a BAN button!
 
#19
Re: Suppression on an AR15

also, so i add some worth to this thread, unlike someone else, a 16" with 77 gn will get you past 600, easily.
on the gas block-no, it isn't a necessity, just nice to play around with, if you were going short it would be worth it, but at 16" you can get away with out it.
I use an 18" and 77 gn with no switch block and a ops inc 12th model. works nice, it gets just as dirty w/ or w/o a can.
btw, either can you are looking at is nice, surefire gets my pic though, with the muzzle brake on that gun there almost NO recoil, and the poi shift is better imo(*having used both) than the aac.
 
#20
Re: Suppression on an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: johngfoster</div><div class="ubbcode-body"> POI shift with the Ops Inc 12th model is almost nil.</div></div>

I tested several other manufacturers cans against the OI on the Mk12 and I agree, the shift from un-supp. to supp. is negligible and it held some of the tighter groups against the rest. However, it was easily the worse can for shift after uninstalling and reinstalling.
 
#21
Re: Suppression on an AR15

true, if i had my way i'd have my surefire on it, but unk sam doesn't like it when you mod his stuff you know?
i just leave it on 24/7, but like i said if i had my way it'd be a surefire- shift, noise reduction, durability -- its the "new hotness" as we say.
stungib, either can will work fine for what you have stated u are looking for.
 
#23
Re: Suppression on an AR15

I have used a AAC/M4-2000 on a 16" DPMS upper and now a 12.5" Noveske Switchblock upper. And, I can tell you that the Noveske is a great upper and they have won my business. When I go suppressed I use the Suppressed lever on the switchblock with 60 GR VMAX reloads and have had zero issues with it. When I used the suppressor on the 16" non-switchblock it works but man does it blacken the brass while using the switchblock on the Noveske it darkens them but not near as badly.

I zeroed the Noveske without the suppressor and then put it on waiting to see what the POI shift would be - nothing, exact same spot. I think that has to do with the rigidity of the 12.5" but may be wrong as I won't have another 223 Noveske to test that theory with.

So, is the switchblock worth the 200 bucks - I would say yes if I am trying to make the very best upper I could from the beginning. But, I would look at just buying a Noveske upper with an AAC 51T mount on it and be done with knowing that is a great upper and it will work to what you are doing.
 
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