7.62X39 heavy and sub-sonic

IRC

IRC

Regular
Rating - 100%
40   0   0
Location
Victoria
Does anyone have experience loading 7.62X39 sub-sonic for an auto loading rifle. I have read tons of stuff for bolt guns or autos with the operating rod removed but have not been able to find a load that will cycle the bolt and remain subsonic. I want to mimic the concept of the 300 whisper in my CZ 858. For components, I have a bunch of commercial brass and heavy (for 7.62X39) 303 bullets. Red dot seems to be the powder of choice of all “pistol powder in rifle case” loads, but I would love to hear your experiences if you have any.

Please don’t bother posting your dire warning about safety etc unless you have experienced something going wrong with a similar project.

Cheers Jim
 
Well,I been loading this calibre with 147 Gr FMJBT bullet and 25Gr.of powder
and they were much more accurate then standart military loads(123Gr bullets with 23/23.5 -yeah,various powder charge-...
Regards
Zygy
 
Closest I have come is with 185 gr lead bullets using 2400 and Surplus WC735 velocity was still 1500 - 1600 fps which is above the speed of sound.

Seating a bullet much heavier than 185 gr is going to be difficult unless you have a good part of the base inside the cartridge below the neck of the case.

Good luck and let us know how you make out.

Take Care

Bob
 
I don't shoot 7.62 x 39 so can't help you with subsonic loads that will cycle your action. Have been shooting subsonics in .222...223. 30/30..308 and 30/06...338 mag ...444Marlin and .416 rem mag and even the 45/70 as far down as 400 fps .

Used Reddot..Bluedot...unique..bullseye 700 X and the list goes on... from many years back.
In 2007 I started to do up loads useing IMR TrailBoss in about 9 different ctgs. Nearly all calibers "start" loads with "normal" for caliber bullet weights produced velocities in the 900 to 1100 fps range.
Some of these start loads also grouped at or under an inch at 75 yards/3shots on initial testing. Some proved just as accurate at 100 yards in the 1000 -1250fps range also with later testing... as well with higher charges in the .222..223...243 in the 1800 fps(22mag velocities).

Have not done any testing with over 180 grain weights in the .30 calibers.

Hodgdon doesn't condone the use of this powder in any ctgs. other than whats on their website..so no "dire warnings " should you go this route.

They had Trail Boss data for only 2 bottle neck ctgs . and one is the 30/30....the 30/30 win. data.. which I believe would be close to similar case capacity as your 7.62 x 39 and may be of benefit for starter load experimentation with regular for weight bullets and you can work up in weight from there should you wish.

Went through several pounds of this in experimenting ...retired all the other mouse load powders and got 10 pounds of Trail Boss from Higginsons to feed the need.
 
My subsonic load for my .300 whisper is 160gr. bullet and 7.5 grs. AA-9 for 1058 fps. however i don't know if this type of load in the 7.62x39 would cycle the action. No prob. in the bolt action Whisper.
 
Some use the .311'' 172gr. FMJBT from Hornady with a trick: since the bullet won't spin-stabilize easily at these speeds, they use it inverted in the case with the proper OAL. The point now becomes the ''tail'' and acts like a fletching.
Another plus is that it reduces the case capacity and allows safe reduced charges with a correct density.
The rolled crimp at the boat tail makes a very good low-speed meplat and opens up nicely even at reduced speeds.
PP.
 
If you google it, A guy on the net was taking .44 mag data, because it uses heavvy bullets, and has the approximate same case capacity, from what he said, and was making subsonic rounds for coyote hunting. Here's the link http: //members.shaw.ca/cronhelm/762ProjectRifle.html


And this is all the ammo info


http:// members.shaw.ca/cronhelm/DevelopSubsonic.html


Hope this helps!
 
Thanks for all the replies. The Cronhelm sight is what originally planted the seed and is probably the most informative sight I have seen on this idea. Did I mention he’s Canadian as well! Unfortunately he has only developed loads for a bolt/single shot rifle. But his case preparation and pitfall discussion is second to none.

The comparison on case capacity with the 44 Mag is where I intend to start, but I have not been able to get any of the five bullet shapes that I have tried to load from the magazine when loaded backward in the case as suggested in a number of articles. I only want to play out to 100 yards against steel targets so I trust that any bullet stabilization problems will be minimal anyways. So I will leave the backward seating of the bullet for later.

Getting the action to cycle seems to be the sticking point as most guys load this round subsonic for bolt guns. I did get a PM from a guy in NZ that has successfully used AA5744 to launch a 180 gr bullet from his AK at 950 ft/sec while retaining the self loading capability. But he is the only example I have heard of. I find this a little perplexing as from what I can ascertain, there are a number of loads for the 300 whisper that will cycle the AR action while remaining subsonic.

Please keep the comments opinion coming!

Thanks

Jim
 
You must log in or register to reply here.
Back
Top Bottom