Subsonic data for short barrels

[tdale4]

I'm just about finished with my Silenced AR-15. I should be done with it this weekend if I can get a few more hours of garage time. Building the can took longer then I thought it would (yes I have an approved form 1)

Anyway it about time to start loading some rounds

I have found a good amount of data for 16" and longer barrels, but I haven't found data tailored for short barrels

Anyone have any load data for short barrels?

My barrel is 9" 1:8 twist and I'll be shooting 240gr SMKs and 220gr SMKs

Powders I have on hand are H110, Reloader 7, and AA1680 but if there is a better powder out there for subsonics I don't mind using a different powder

Thanks
Tim

[Fritzcat]

I have been testing loads for a couple of weeks now for a 10 1/2" pistol lenth gas block. There are some threads showing 1680, H110, and Lil Gun. I got some Lil Gun at the Tyler Gun show and tried 9gr to 9.5gr with 220gr Horn RN and stayed Sub-Sonic. I have been trying the loads at night, so I have not been able to chrono much, Win 296 is about the same. If you Google a 300 whisper search, you can find Sierra load data and it shows 220SMK and 240SMK subs. and lighter super-sonic with a few powders. I have tried Lil Gun, Win 296, Blue Dot, Unique, and clays on different weight bullets. Have fun and let us know how it goes.

[HUNTER2]

Is the can of your design? Have been wanting to tackle one myself...

[amafrank]

I've done a bit of loading for my 9" barreled SIG and 2400 gave me the most consistant velocities subsonic with Lil'gun doing pretty well for supersonic loads and light bullets. The Lil'gun seemed to be a bit slow for the heavies in the short barrel. The suppressor was designed and built for the rifle and works very well. 2400 is quieter compared to subs with Lil'gun as well probably due to the faster burn. . . I tried some H110 but it seems to have a lot of issues with outside temp so I'm going in other directions. Vihta Vuori N110 is pretty good too and seems to be much less temp sensitive.

Frank

[tdale4]

Originally Posted by HUNTER2

Is the can of your design? Have been wanting to tackle one myself...

No, Not my design. I copied a two point mount design using freeze plugs bent into M baffles.

you can find the one I am using here http://www.silencertalk.com/forum/viewtopic.php?t=19231 You will have to join the forum to view the post

[Drof]

Lil Gun was very accurate and clean out of my 8" ar, but would only eject, not feed. I couldn't get it to operate at all much less reliably. Regretably(for cleanliness) I went to RL7 at 10 gr with the 240gr smk. With two coils cut off my spring it functions flawlessly even locking back in empty everytime. Accuracy seems close, but leaves more powder behind. I'll trade a little more cleaning for dependability any day. I still need to chrony my new load, but it's pretty stinkin quiet with the 7.62SD.