Subsonic 147 gr. load?

[Schneeky]

I did try the aa#5 and it sucked donkey nuts for accuracy.

Hehehe.. Izzat an "industry term".? Hehehe.. d:^) Schneeks..

[-k-]

One key point missing here is the AR barrel or bolt gun used by different people. The new 300 BLK barrels should not be able to cycle the lighter bullet loads, or they will be like the old 300W/300-221 and cycle too fast with supersonic loads.

The 300 BLK subsonic ammo and barrels designed to shoot it are a significant improvement and reliable for a serious use with subs and supersonic.

For a fun gun and mainly subsonic you can get a pistol gas barrel and a set of drill bits to open the gas port, or an older 300-221/300FB barrel.

[BELT_FED]

The Guy posted it was a 10.5 barrel with a 3 way gas block and some other buffer. Ill see if I can find the thread again and cut and paste it.


ah here is the quote and it was a 150gr not a 147 my bad


It's an AR with Ron Williams 10 1/2" Poygonal 1x8 and Paladin 3 way gas block in pistol position and YHM 9mm Wraith XL. The loads I like best so far is Horn 220gr-9.5gr-Lil Gun, Speer 200gr-9.2gr-Lil Gun, 175 FMJBT-6.5gr-Blue Dot, Nosler 168gr Match-6.5gr-Blue Dot, 150gr FMJFB-6.5gr-Blue Dot. All of these cycle and no sighns of pressure and quiet out of the 9mm Wraith.

[dbrown]

For a cheaper subsonic load I have been using the 208 amax and H4198. It works pretty well but cannot attest to the sound...still pending 140+ days

[Garrett]

I tried a slower powder, and it did in fact cycle the action. At least until all the unburned powder gummed up the action so bad that I had to completely strip down and clean the gun, bolt carrier group, and trigger group before I could continue. Apparently there's enough gas volume, but chamber pressure is way too low to get a good burn.

The gun was cycling 147 gr. surplus bullets at speeds under 600 fps.

-k- makes a good point about various chambers, etc. I'm using a Noveske .300FB barrel with the gas port in the pistol position. Since I don't plan on using this for screaming fast supersonic ammo, I see that as a good thing. With a properly specced 300BLK barrel, all of this may or may not work.

[JohnInNH]

I tried a slower powder, and it did in fact cycle the action. At least until all the unburned powder gummed up the action so bad that I had to completely strip down and clean the gun, bolt carrier group, and trigger group before I could continue. Apparently there's enough gas volume, but chamber pressure is way too low to get a good burn.

The gun was cycling 147 gr. surplus bullets at speeds under 600 fps.

-k- makes a good point about various chambers, etc. I'm using a Noveske .300FB barrel with the gas port in the pistol position. Since I don't plan on using this for screaming fast supersonic ammo, I see that as a good thing. With a properly specced 300BLK barrel, all of this may or may not work.

Good point. Balancing the burn rate is important. To slow will cause just what you report when selecting a powder getting the chamber pressure up into the efficiency range is important. The extreme spread gets a lot less when you get the chamber pressure in the right range.