Subsonic Load Success/Lessons

[AFDoc]

Good morning ladies and gentlemen,

After a recent search it seems we haven't discussed this topic in while. Let's discuss your recent/successful load development and lessons learned.

What powders are you currently using? Red Dot? Trail Boss? RL-7?
What bullets do you favor? Flat nose? Spire point?
Have you found it necessary to drill-out the flash hole and use magnum primers?

I am getting ready to develop subsonic loads for 7.62x39. I have some 180gr flat point cast lead bullets on order, and I plan to start with Trail Boss. As I go forward, I hope to be able to post some useful information. In the meantime, tell us about your subsonic load development.

Thanks,
Travis

 

[kingmt]

I use a powder faster then Bullseye & anything up to add fast as Blue Dot.

 

[mtrmn]

First I will say that IN MY USAGE subsonics have no PRACTICAL purpose other than satisfying my curiosity and demonstrations for folks who've never experienced suppressed weapons. I just get a grin on my face when I play with them.

I have used Trail Boss with much success on 308 and 223 subs. No mods made on the brass. Just kept reducing loads til I no longer heard the supersonic crack. I did use CCI military primers which are magnum primers according to CCI website.

When you reach the borderline point of no longer breaking the sound barrier, I suggest further reduction of the loads a bit. When I settled on a load that was quiet, I'd shoot the same ammo under different conditions and get 50/50 results. Some would crack and some wouldn't.

I'm at work and can't remember any of my load specs.

Testing every style bullet I had in water, I never once got any expansion/mushroom out of my bullets at subsonic velocities. If intended for hunting, make only head shots and limit ranges to like 75 yds or so. Flatnose cast may be best for this purpose. There are special bullets made especially to perform in subs, but I bet they're impossible to find now.
Much better performance on small game will be achieved with 22LR subsonic HPs than 223 subs. Stick with bigger calibers for hunting.

ALWAYS test your loads WITHOUT your suppressor to make sure bullets are stabilized before you install your suppressor and destroy it with the first shot. I did this by putting up cardboard close to the muzzle, more at about 20 yds, then 50, 75 etc. You need to be shooting little round holes-not keyholing. Test several rounds.

 

[Lennyjoe]

I've used Lilgun and 200gr Speer hot core in my 300 AAC that stayed subsonic but won't cycle the bolt enough to chamber a new round. Don't have the suppressor yet so it was just for fun.

Once I attach the suppressor, I plan on using 208gr Amax or 220 Sierra Matchkings over AA1680 for starters.

 

[jmorris]

I probably load more 405 grain JSP's subsonic than anything else. Like mtrmn said a lot of them are about useless, like subsonic .224's.

You get the mass up and you again have usefull energy although at a pretty limited range.

I use mine for hunting hogs at night with a suppressed 458 socom, more often than not CCI LP primers and HS-6.