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My Latest 7.62x39mm SubSonic Loads, Forget Puff Lon!

Posted: Tue Jun 17, 2008 5:57 pm
by tgbrowning
I made it out to the range again today, Tuesday 17 June 2008, to try my latest loadings in my search for reliable, accurate, and safe subsonic loads for my AR-15 in 7.62x39mm.

I started with the 180 grain Remington round nose bullets I had remaining.

I recorded he following data, using 10.0 grains of Hodgdon H110 powder, CCI 250 primers, Winchester cases trimmed to 1.520â€

Posted: Fri Jun 20, 2008 6:22 pm
by Artful
Good to know, sorry it didn't work better for ya.

308 subsonics

Posted: Sat Jun 21, 2008 3:28 am
by David Hineline
In my 308 rifle I am very happy with IMR Trail Boss, the powder is shaped like fluffy doughnuts so a loading of 10grains gives about 70% case fill in a 308 case. I suspect in the X39 case it would pretty much fill er up.

In my 26" rifle 8grains keeps 150gr pills subsonic
8.5grains works with 20" barrels and 150gr bullets

9.0grains works for 180 grain bullets.

Posted: Sat Jun 21, 2008 8:06 am
by pmercer
tgbrowning, I'm not familiar with puff lon, but I get the idea you're trying. I use couc cous (from the supermarket) to fill the void in my Ruger Old Army(only on my local range because of the noise).

Maybe you could try using that. I also would calculate how far into the case the bullet is going and only fill to that point. Just make sure there is no air gap or as the rounds get bumped around in your bag the cous cous and powerd can swap ends.

Posted: Sat Jun 21, 2008 9:23 pm
by Artful
Cous cous wouldn't be consumed in firing and would clog a suppressor as well as act like a high speed abrasive in your suppressor. At least that is how I envision it acting. :shock:

Posted: Sun Jun 22, 2008 2:05 am
by pmercer
I agree. I didn't realise I was on a silencer forum, sorry. :wink:

seriously though, we never see the cous cous on the rage after firing it, although we we think it burns away as it comes out of the barrel. Maybe some more investigation is needed.

Cous Cous or Puff Lon

Posted: Sun Jun 22, 2008 6:50 am
by tgbrowning
With the loads I've developed so far, I don't think I need a ballistic filler of any sort.

I intend to try some different powders for my next loads. For one, I am considering trying some Trailboss powder. It seems to be the powder of choice with 7.62x51 (.308 Win.) So, I am curious how it might work in the smaller 7.62x39 case, but I'm not sure the case has sufficient capacity for this powder.

I am pleased with the loads using H110 because 11 grains fills the case of the 7.62x39 about half way and the 220 grain bullet fills the remaining space pretty well. And the chronograph numbers are good. My main interest in trying a different powder is based on reports of temperature sensitivity with H110.

If anyone has ideas for a good powder/bullet combination for 7.62x39mm subsonic loads, I am always glad to hear them.

Thanks,

tgbrowning

Posted: Sat Aug 16, 2008 2:24 am
by d-mon
Hello tgbrowning,

Have you tried to weigh your cases and separate them in different groups?

And see if you obtained diffrent speed reading?

Nico

Posted: Tue Aug 19, 2008 5:03 pm
by tgbrowning
d-mon asked:
Have you tried to weigh your cases and separate them in different groups?

And see if you obtained different speed reading?
No, I haven't. But, I do separate the cases by head stamp.

Next, I will be loading some 200 grain Lapua purpose built subsonic bullets I finally received. I am also trying a couple of different powders. I have found a load that will cycle the action of my AR-15 7.62x39 about 50% of the time, but I want load that will cycle everytime. So, weighing the cases may be an option to reduce the number of variables in my load testing.

T.

Posted: Thu Oct 02, 2008 10:55 pm
by wolf
Try using the powder you can get some of that is a tad slower
you will need a bit more to get the same velocity's but the pressure will "stand" a bit longer ,or you could say the pressure will peak a bit later meaning you get more pressure for the cycling ,and thats what you are missing to make it make a full cycle

Posted: Fri Oct 03, 2008 6:03 pm
by tgbrowning
Thanks for the suggestion. Just exactly what powder did you have in mind?

T.

Posted: Fri Oct 03, 2008 6:24 pm
by wolf
I am in Europa so i am not so used to Us powders
i mostly use Withavuori its a powder from Finland , but i think you can get it in US to
N110 is slightly slower than H110 so that might do the trick ,,if not then N120
Or some like it
The N110 is very temperature stable meaning it dosnt give big variations depending on the temperature
It also is very forgiven about low pressure = it stills burn clean in a less full case
A q to you ,does you cases get black around the case mouth ? if yes then the case isnt giving a god seal
The bad part would be that the solution for that would be a faster powder :roll:

but if you size you cases so that they are just sized enough to freely chamber it might help
I have used the LEE collet die for that reason
It only sizes the neck+ you dont have to lube the cases and is giving a god seal , but you have to use cases that has been fired in you gun to do the trick

Posted: Tue Dec 08, 2009 2:32 pm
by clay_breaker
I know this is an old thread. But has anyone got any new x39 loads to share.