Thread: Subsonic 300BLK , AR15 loads

Hi Guys ,

I am after a powder/load for 220gr SMK at subsonic speed , that will cycle a AR15 , thats running a pistol gas tube lenght , I know in the USA the go to subsonic powder is AA1860 , but I have not seen this powder in NZ ?

Cheers Chris

Hi Chris,

I have had best results for reliable cycling with VV N110, 2205 didn't seem to produce enough gas for my setup. However when shooting 168CF Lehighs 2205 was superior for consistent speeds and N110 terrible.

Good luck.

H4198 works for me, still working my load down,
some success with H4227 (same as AR2205), would cycle but no bolt hold open

I had to open up the gas port on my barrel to 2.3mm to get subs to cycle (11.3" wilson with pistol gas)

Originally Posted by Bugbait

I have had best results for reliable cycling with VV N110,

whats your load and what projectiles?
barrel specs?

Originally Posted by Glycerine

whats your load and what projectiles?
barrel specs?

240smk @9.5 N110.....180smk 10.2 2205.....230Berger hybrid tac @ 9.5 N110.....Lehigh 168CF @ 9.75 2205(crimped).....Lehigh 194ME @ 9.3 N110.

The barrel length is 12.5" True flight ultra match with a 1 in 8"twist and a suppressor. Pretty sure it's pistol gas but unsure if it's opened up. I bought it a while ago(second hand) and it is actually a 300 Whisper.

Like you the 2205 would cycle (most times) and have no bolt open, pretty good for the supersonic though.

I may try "little gun" at some stage that's meant to be good in subs.

Cheers.

Thanks, I'll try some N110 loads, see how they go.

my W296 loads with 230gr cast lead projectiles from trademe cycled in my mates rattle gun, only fired a few though so can't comment on them otherwise

11.5" tru flite, 1-8, GW Maximus can, hybrid gas length (between pistol and car) 230gr cast lead RobertW on TM. SR primer, 9.3gr WW296 1006fps avg. 1.5 MOA gps 100m.

Remember when ladder testing subs start high and work down.

Bolt lock back on empty means enough gas.

F

Originally Posted by 300_BLK

11.5" tru flite, 1-8, GW Maximus can, hybrid gas length (between pistol and car) 230gr cast lead RobertW on TM. SR primer, 9.3gr WW296 1006fps avg. 1.5 MOA gps 100m.

Remember when ladder testing subs start high and work down.

Bolt lock back on empty means enough gas.

F

Almost identical load, I use 9.5gr of W296 in the Ruger Ranch but get the occasional super sonic round at different altitude. I couldn't find W296 so use the Belmont version

Yeah ,

Thanks Guys , I will pick up some powder from Belmont tomorrow ,

For plinking I use 155g pill and 10.0gr of IMR4227 ,through a 10.5" barrel and Pistol length gas system.. is accurate enough,is Subsonic and Extremely quiet !
Bolt holds open on last round also

Yeeap ,

Just shoot the 300blk for the 1st time today , using 9.5gr of Belmont ( WC296 ) & 220gr SMKs , speed is 1050-1098 fps, and it cycles , but the converted brass I am using is in short rubbish .
Will try 9.3 & 9.4gr , But this powder is super fine , and a bit fiddly .

This is from a 1-8 twist , 10.5 inche barrel .
with pistol gas lenght .

I've found the ADI mil serp once fired good for converting,

I've also found resizing back to 223 first then cutting brass makes it easier to resize to 300blk and gave me a better results
rather than just cutting and sizing to 300blk

Yeap ,

I brought this brass , I did not make , it , IF I had it would be much better .

Just tried some more subsonic , 220gr SMK ,

9.3gr of WC296 , 997fps Av

9.4gr of WC296 , 1007fps Av

All cycle the rifle good , no problems , used the holosun & 3x , worked good .