7.62x39 subsonic handloads powder


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civilian75
April 30, 2009, 03:43 PM
What is your favorite powder for subsonic handloads for your 7.62x39 bolt or single shot rifle? Why? With what bullet(s)?

I want to develop loads to shoot at ~1000fps for jacketed .308 cal bullets a light as 150gr and as long/heavy as 220gr-ish .., all permiting. I want to avoid cast bullets for I am not ready for another hobby. And, of course, I want 2-3 MOA or better at 100 yds, all permiting.

I am experimenting with Trailboss but I am getting very incosistent MVs, consistent with other people's findings, for this powder was developed for cast bullets. And not just that, whereas in .308 Win cases I am left with lot of empty space, in 7.62x39, I have to compress the load (!?!?!), which kind of tells me I should switch powders.

If you are wonderin, right now I am shooting them thru a Yugo SKS but I am shopping around for a Rem799, CZ527 or a Rossi single shot. I like the CZ the most because of its 1:9 twist rate, ideal for subsonic work, and good reports with .308 bullets. But I hate the price, low availability and cheap looking mag. Plus, I will thread and suppress it, so the front sight will most likely have to go, which kind of pisses me off.

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civilian75
May 4, 2009, 12:43 PM
bump :(

freakshow10mm
May 4, 2009, 12:54 PM
I don't load x39 but most of my rifle subsonic is loaded with IMR's Trail Boss.

Clays and TG can be used. Put some cream of wheat in the case to keep the powder near the primer.

civilian75
May 4, 2009, 01:33 PM
FS10mm,
What do you do to obtain consistent muzzle velocities. Mine are all over the place.

Walkalong
May 4, 2009, 01:36 PM
I have to compress the load (!?!?!), which kind of tells me I should switch powders.IMR says NOT to compress Trail Boss. You may know that already.

civilian75
May 4, 2009, 01:46 PM
crazzy muzzle velocities where on 35-50% filled cases (.308 Win & 7.62x54R). I have not yet had a chance to clock the 7.62x39 loads.

And yes, I forgot about the "do not compress". So more reasons not to use TB with 7.62x39.

Walkalong
May 4, 2009, 01:51 PM
You might try IMR's SR-4759, or AA's 5744, both intended for reduced loads in rifle calibers. I have some of both. Good stuff, although I have not used them for their intended purpose.

civilian75
May 4, 2009, 02:25 PM
I though about IMR's SR-4759 and AA's 5744. The problem is that QuickLoad predicts I'd be filling the case approx 40% in reaching the desired subsonic speeds, which is precisely what I wanted to avoid when I picked the 7.62x39 for subsonic loads.

I'd like cosistent muzzle velocities with copper jacketed and approx 80% or better case filling.

There is a handfull of IMR powders Quickload predicts will meet this requirement. I wanted to see empirical results. Before I keep throwing money into the problem.

It can be done. It has been done. (see ebr-inc.net).

civilian75
June 9, 2009, 08:08 PM
Last weekend I loaded 220gr RN in top of 14.5gr of IMR4198 on pulled Golden Tiger cases and got excellent results on a AMD65 SBR, IMHO.

I had also loaded the same bullets on 14.0gr of IMR for my Yugo SKS but fired them on the AMD instead. I was pissed at my temperamental Yugo. But it should have been very close to subsonic. Anyways, 14.0gr is as low as I am willing to go with 4198 in 7.62x39 cases. I will need to look into SR4759 for my SKSs, once I solve its accuracy issues. #$%^&*

But, going back to the AMD, the bolt cycled just fine every time. It generates enough pressure on the bbl at the gas port to clycle the bolt carrier consistently. I got 1030fps ave. And, I even hit the target at 100yd (rear sight at 600yd) 2 out of 3 with open sights (my aging Mark1 eyeballs do terrible with open sights). This is an accomplishment given the poor accuracy history of subsonics on the AMD SBR (13").

A note of caution. The 220RN rounds may not load on some AKs. In mine they did not. I had to slightly ramp both the trunnion and the breech face, mostly smoothen the sufaces and make them curved vs. straight angled. That did the trick. Also, I am actually sitting at 2.200". When the round gets stripped from the mag and pushed into the chamber, it gets re-seated another .020" approx, thus, obtaining a final 2.180" COAL. One additional area for improvement.

Bottom line, a heavy bullet plus a not so-fast-fast rifle burning powder is doing the trick for me. Now, I am going to focus on reliably keeping the SEE (secondary explosion effect) out of the picture. As per Quickload, the 7.62x39 case is filled to 75% in this load, seating the bullets to a 2.180" COAL. I need to somehow determine if a 75% fill is not only 1) full enough for consistent even firing form round to round, but, 2) will keep SEE away 100% of the time with IMR4198. I just don't know for sure...

ActionYobbo
June 9, 2009, 10:29 PM
I am using 6.5g or trailboss with a 220 grain cast bullet in a RP case. I have found the small primer is the key to consistancy. I use these from a 16" barrel with a 1 in 10 twist. MV is 950 to 1000fps depending on the day. you know temp and humidity etc. group sizes are about 2" at 100 yards but I am using a very old 3x32 scope. I could also do better if I batched the bullets and did some work on the cases.. penetration is good. will go through 1/4" mild steel at 25 yards and will go through 8" of pine at 50 yards.

these loads wont fit into the AK mag they are too long.

Kernel
June 10, 2009, 12:59 AM
+1 IMR's SR-4759, or AA's 5744. These are two of the best for reduced loads. These powders are specifcally made for this purpose. RL-7 will work well in some cases. Red Dot or Unique if you prefer more traditional pistol powders.

kiwi**
June 10, 2009, 06:02 AM
I do subsonic reloads for 7.62x39
and use 308 soft nose 150gr projectiles with 8.5gr of w296 powder, you could do 9 or 10grs.
You must use large pistol primers and pack dacron on top of your powder to keep in place when chambered in you gun, you will hear the primer only going off.
I use this with silencer also and makes it very quiet.
This is for my saiga rifle, it wont cycle so you have to do that by hand. Just check and make sure the bullet leaves the barrel. I have not had a problem but the first few shots to be SAFE CHECK IT.
Hope this helps.

civilian75
June 10, 2009, 12:02 PM
Kiwi
I've stayed away from Dacron mostly because I've read so much against it in necked cases (ok for straight walled cases, though). What's your take? Also, what type you use and where do you get it? Only I've seen is the little patches made for muzzle loaders (pricy as heck!).

civilian75
June 10, 2009, 12:29 PM
Back to the powder topic, I would definitely use a faster rifle or even pistol powder for a load developed for a bolt or single shot rifle. Now I am focusing on developing a load for a AK47 short barreled rifle (AMD65), with the following goals, in this order:
1. No detonation, or SEE (obvious).
2. cycle the bolt carrier 100% of the time.
3. stable out of the muzzle (for my suppressor's sake)
4. 4" groups at 50yd with open sights

This is just for plinking fun, shooting a 8" armored plate at 50yds.

For my Yugo SKS, I will work up a faster burning powder.

For hunting, I might get a mini Mauser (Rem799 or a CZ). I might even get me a t/c encore/contender frame and bbl. But, man, they are pricy! Accuracy goals would be much more aggressive.

I've kept evaluating my powder choice. Ran numbers on published reduced load data on Speer's #14 manual. They published a "safe" reduced load with 25gr of IMR4198 under a 125gr .308Win. Quickload calculated a 57% fill. That is pretty low! In my case, 14.5gr under a 220gr fills 75% of the 7.62x39 case, a 18% improvement. The only thing that troubles me is that I've been using Berdam primed cases, with two flash holes! Boxers are coaxial with the case, but, with Berdam one of the flash holes could end up very high in the case, where there is no powder! That is why I feel 75% fill is my absoulte minimum in this case. Thus, the Dacron wad question. Or, I could switch this load to brass/boxer primed cases, to buy me some more safety margin.

Ranb
June 10, 2009, 01:47 PM
I use WC820 (surplus 30 cabine powder) for all of my subsonic rifle loads including 223 rem, 300/338/510 whispers and 458 socom. Any magnum pistol powder should work well for a subsonic 7.62x39. WC820 is just a bit faster than H110. N110, 296 and 4227 should also work well. My loads only fill the case about half way, but I still get low stdev's and never a squib load. I do not use a filler. My subsonic 223 do not cycle the ar-15 action.

Ranb

kiwi**
June 11, 2009, 01:36 AM
I use boxer primed cases to get good detonation and you can also use cigarete papers rolled into a ball or cotton wool as well for a wad type stopper to keep powder in place.
Cheers

civilian75
June 19, 2009, 10:35 AM
kiwi,

There's a myriad things one could use for wad paper. My favorite is toilet paper. I'd still like to know where you get the Dacron, just in case.

Also, I'd appreciate it very much if you or anyone else could explain why there is so much apprehension over wads on necked cases.

I've been getting very good ignition with Berdan primers. Surplus Berdan could be suspect in the case of the horrible results I obtained with 7.62x54R Bulgi surplus. I pulled the ball bullet, removed the powder, replaced it with TrailBoss, and seated the same 182gr FMJ back. Next time I switched to the 220gr RN and the difference was immense. I don't thing, though I do not have the data to prove it, the issue was as much the Berdan primer or the fact it is a surplus case, but the combination of a relatively light bullet, a large 7.62x54R case and TrailBoss.

tkcomer
June 19, 2009, 01:24 PM
You can study this web page: http://www.leverguns.com/articles/paco/small_charges.htm I use about 9grs of Unique in my low power 30-30 loads for my lever gun. Of course those are cast bullets. But you might get an idea of what powders to try. Might also give this page a look: http://www.quarterbore.com/300whisper/subsonic.html

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