AR Silencer Question

[SharpsDressedMan]

Regarding subsonic .223. Why bother. For all the hassle of specialty loading (or paying high bucks for someone ELSE to load it), worrying about stability of heavy bullets in the wrong twist barrels, etc, just shoot .22LR. Not much difference in Aguila 60gr SSS at 900-950fps and a 55-68gr. .223 @ 950fps.

 

[Ranb]

I can load 70 grain bullets that stablize in a 1-9 twist AR-15. With a twist of 1-7 I could go as heavy as 90 grains. Since I load my own, I can go right up to 1050 fps. Winchester standard velocity 22lr ammo moves about 1040 fps out of my Marlin. The 60 grain SSS moves about 700 fps at the most in my rifles. KE is proportional to the square of speed.

90 grain at 1050 fps is 220 ft-lbs
70 grain at 1050 fps is 171 ft-lbs
40 grain at 1040 fps is 96 ft-lbs
60 grain at 700 fps is 65 ft-lbs

I do not know what you are getting 950 fps with the SSS in, but I do not get that in my 10/22, Marlin 25N, 10 inch Buckmark or my TC contender. In the 10/22 I get lots of noise from the ejection port when using SSS. The accuracy is poor compared to the winchester subsonic ammo. While others may get better results, and I'm sure I can do better with a faster twist; in my guns the SSS ammo sucks. I will not shoot it in my suppressed guns due to stability concerns.

When handloading, there is no need to underload to ensure that the ammo remains subsonic. Even when using temperature sensitive powder like H110. A streamlined jacketed bullet weighing 70 grains is going to way outperform any 60 grain rim fire bullet moving 950 fps. I like my 22lr rifles, but they take a backseat to performance when talking about power.

Ranb

 

[SharpsDressedMan]

I was just ASSUMING SSS runs just under Mach 1. I load all my subsonic stuff in the 950-975 range to eliminate all variables that MIGHT push the round over 1050 (even different altitudes might not be at 1100 for Mach 1. To me, if you MUST have subsonic loads for a suppressed .223, you also need to know where to reset your sights if you go back and forth from supersonic to subsonic. Pain in the butt. Get a .300 Whisper or .300/.221 upper for your AR. The improvement of the .300 over the .223 is so good, you'll never want to shoot .223 subsonic again. AND, you can utilze a .30 cal suppressor on a .223 if you need to.

 

[Ranb]

Altitude (air pressure) does not have much of an affect on the speed of sound, it is mostly temperature related. The speed of sound varies from 1050 fps at 0 F, 1087 fps at 32 F, to 1149 fps at 90 F. The temperature where I shoot in WA is rarely outside of the 32-80 F range, so loading to 1050 fps works well for me. 1050 fps shoots flatter than 950 fps.

Ranb

 

[SharpsDressedMan]

Ranb, you are one the money. We have so many changes in climate in Ohio, and also dealing with variables in cases & capacity, that going a tad slower eliminates possible velocity rise and "crack". Flatter trajectory is nicer, but once I have a fixed velocity to work from, just knowing my drop, and having my ballistic table at hand, I can correct for any loss of an advatage in drop from 1050fps to 950fps. The ft/lbs loss isn't going to be significant (especially with the .300 over the .223.)

 

[Ranb]

From what little I have read about ballistics, shapes and transonic affects, going a bit slower than 1050 fps can eliminate turbulance when using certain bullets. I use round nose for most of my subsonic loads except for the Sierra hpbt match on the 300 whisper and ball or amax on the 510 whisper.

Pushing them to the limit of the speed of sound is working good so far except on the 458 socom which is giving me some problems and the 220 grain RN in my AK whch is completely kicking my ass right now in the accuracy and cycling departments. I do not know if it is the speed or something else.

Ranb

 

[SharpsDressedMan]

Ranb, what's your twist rate in the 7.62x39 with the 220's?

 

[Ranb]

No idea. I just mashed some loads together that fit in the mag and went to the range to clock them. All I found out was that 220 RN does not feed in my rifle, WC820 hot enough to push the bullet 1200 fps does not cycle the action and accuracy at 25 yards was 2 inches. It will be a while before I can do anymore testing. My limited google search has not revealed any standard twist rates for the WASR in 7.62x39.

I have read claims that EBR ammo (>$1/round) cycles the action and is accurate. No way I will buy it at that price though. Subsonic is merely a novelty in my WASR and I have much better results in my AR and contenders with the slow stuff.

Ranb

 

[Ironman]

The suppression is extreme.

Metered example-

Ruger 10/22 16" bbl HV .22lr ammo- 140.5dB
AR15 16" bbl .223 Federal ammo- 165dB
AR15 16" bbl .223 Federal ammo, AAC M42000 MOD08 suppressor- 132dB

OSHA states you have unsafe sound levels at 140dB, a suppressor on a AR15 looks like a no brainer. Kinda why I have one.

Get one and dont look back.

 

[killntime]

Anybody know if a threaded or lugged suppressor is better?