AK Rifles banner

Subsonic 7.62x39 loads and development

42K views 14 replies 10 participants last post by  Sauce06 
#1 · (Edited by Moderator)
I wanted to start this thread to post some of my findings for loading subsonic 7.62x39. I have had some members ask previously to post my load data. So I will continually update this thread as I come up with new loads and range reports. For now, I am generally listing info and not specific load data because of the many variables concerning the subject. I currently do not have any pictures of group sizes from past experiments but I will do some shortly and post them here for members to see. Also if other members would like to share their info and experience don't be shy.

Please feel free to list your Firearm, barrel length, suppressor type, and load data.

First off this is NOT a guide or how-to. This is strictly my own findings and I DO NOT encourage anyone to try and use any of the data I am going to list in this thread. Reloading is extremely dangerous especially when loading subsonic ammo. You endanger yourself, your firearm, and your suppressor while doing so. I am not responsible for any injuries or damage to you or your equipment. If you plan to load any type of ammo make sure you have sufficient knowledge and skill to do so competently.


Here are my two test rifles
Top SBR has 11 1/2 in barrel
Bottom Yugo M70 16 1/4in barrel
AAC 7.62 SD Suppressor



This is not finished data only experiments with IMR 4227 and different weight projectiles

From left to right are the lightest to heaviest projectiles

110gn FMJ .308 cal ONLY projectile that is not .311-.312
123gn Hornady V-Max
124gn Tula SP
147gn 7.62x54R pulled projectile
150gn Sierra Spitzer
169-170gn Cast lead powder coated projectile LEE Mold CTL312-160-2R
174gn Hornady HPBT
180gn Sierra Spitzer
180 gn Speer Hot-Core Round nose
188-189gn Cast Lead powder coated projectile LEE Mold C312-185-1R



Projectiles Seated to 2.200 to show how deep some projectiles seat into the case.
110gn FMJ is just seated about .250 into the neck of the case



Cases have a modified flash hole opened up to a #40 drill bit at .098
Using CCI #.200 large rifle primers

Generally speaking for my rifles

I have found that a safe charge of 11gn of IMR 4227 will Push ANY weight projectile I have listed subsonic out of the Draco SBR. All projectiles will stabilize with this charge as well and none will travel less than 900 fps. Cycling will depend on your particular firearm but the 110gn does not cycle at all and the 180gn round nose will give me feeding issues. I tend to push mine a bit slower to achieve a quieter sound generally around 950-1000FPS. I live about 350ft above sea level and at 1060fps I get a supersonic crack. 950-980FPS is where I like to keep mine for ultimate quiet but not all loads function properly at that speed.

My loads out of the full-sized AK with 16in barrel had to be reduced slightly. 10.5-11gn of 4227 to stay subsonic. I have shot most loads out of this rifle but cannot get consistent data from the worn barrel.

Function and FPS depends on your particular rifle. Always start High with your loads and reduce the charge to achieve the desired function in your particular AK. A good starting charge of 12gn with any of these projectiles will safely get the projectiles out of the barrel so you don't get a squib.

For reference only do not use
From Draco 10.5in barrel

110gn FMJ 10.5gn 988fps
123-124gn 10.5gn 900fps
147-150gn 10.5gn 1015fps "147gn 54R steel core projectiles do not stabilize below 10.5gn and 1000fps"
170gn lead projectile 11.6gn 1005fps
174gn HPBT 10.5gn 1037fps
180gn Speer Spitzer "could not find my previous data"
180gn Speer Hot Core round nose "could not find my previous data"
188-189 Lead cast projectile 11.1gn 990 fps

Data for Full sized AK with 16.25in barrel too inconsistent will list some good results though. I could not locate my old load data with other projectiles but will update the thread when I do.
169-170gn lead projectile 10.6gn 980fps
188-189gn lead projectile 10.5 964fps

Will be updating this thread as I find more of my info and range test these loads and projectiles more. I'll post some pics of accuracy and generally FPS readings.
Arsenal SAM7K SBR Krink data still to come.
 
See less See more
3
#3 · (Edited)
Back when 22 rf started getting scares an pretty much still around here is although I don't shoot that much of it I started looking for a sub sonic load that I could use in all my US and Foreign 30 cal. rifles using one standard bullet and powder. The rifle are the 30-30 / 300 Sav. / 06 & .308 Win / 7.62 x 39 & 54r. After talking to a couple old casting friends I decided to go with the Lee 32 cal. .314" 90 gr. tumble lube SWC the bullet drops from my mold at .315" as is sized down to .314" for the SKS and Mosin and sized to .311" for everything else. The powder I use is Alliant Bullseye in the smaller X39 case I use 3.0 grs. in everything else I use 3.5 grs. no filler is need as the powder ignites easily using either LR or LRM primer.

I cast the bullets from pure lead or 3 parts lead to one part WW and lightly tumble lube with my Alox/JPW lube once before and once after sizing. Bullets are lightly roll crimped in the top lube groove but you can play with the length and extend it out a couple groove to see if it improves accuracy. To date the highest MV i have clocked on the chrono is just under 1100 fps. out of the old Sav. pump 30-30 Average groups with iron sight run 2" or under at 50 yds.



 
#6 ·
NXCHESTER: thanks for the in-depth, separate thread response to my question in the other thread. Lots of good info in your post.

R762: you're the second person I've heard about using tiny amounts of Bullseye in large rifle cases without issue. Seems like the reason to use BE in 9 and 45 applies in this case (pun intended) as well: more rounds per pound:)

Thanks all for the data. My only exposure to subsonic reloading has been 300BO with AA1680 and .308 with Trailboss, but once I clear up the other reloading projects in front of me I'll eventually get into 7.62x39 subs.
 
#7 · (Edited)
Off topic of sub x 39 loads. I have other data for sub loads for .308 and have some good data out of my Rem 700. I mainly use commercial #1 shotgun powder because i got 8lbs of cheap a few years ago. It works well and gets a consistent burn and velocity. Only recently have i been able to get Trailboss. I picked up a 1917 STHLE a few months ago that couldn't hit the broad side of a barn so i cerasafe cast the chamber and barrel to see what was going on. My large barrel diameter is .315 and small diameter of .312. So i am casting my own projectiles sized to my barrel and using trail boss powder. I started off with a lite load at just a bit over 1000fps and shoots well now. I plan to load some moving faster in the future and see how it goes.
My pet load for my .308 Rem 700 is about 10.5gns of commercial #1 powder pushing a 190 SMK. With the 1-10 twist the 190 SMK performs we'll in the subsonic range i have got my best accuracy with this projectile. I have shot it at 300yds and was able to get about 3in groups with the shitty stock trigger. Also this load fire forms the case with only sooting around then neck and doesnt go past the shoulder of the case. Once fire formed i only neck size this way i can get many used from my cases. I have about 15 loads on some cases but thats about all i can get the flash hole gets eroded pretty bad after about 10 firings.
 
#11 ·
Ok,
So rehashing an old subject with a new projectile...
Has anyone tried loading the Hornady 190gr Sub-X in 7.62x39?
I know they are .308" not .310-.311, but wondering if any has tried this or any other Subsonic loads since this thread started.
I recently got a PSA AK setup with a suppressor so I'm itching to try some subs after running standard ammo thru it.
Thanks.
 
#12 · (Edited)
I wouldnt advise using .308 cal projectiles for subsonic loads. They do not seal consistently or effectively for them to be safe. Ive done lots of testing with them just for shits and giggles but wound up with many squib rounds in the barrel. When doing things like that you load one round, fire one round, look, listen, and inspect after each round. Youre visually looking to see did the round hit what i was aiming at or did it leave the barrel at all. Did my chrono get a reading. Did the case eject? What does the case look like. And lastly inspect the gun.

I purpose built a 10.5" ak just to test subloads and didnt care if it got damaged in the process. Cheap sub $500 sbr including the tax stamp using a junk centerfire systems draco kit. This was back before the world went crazy and aks cost more than a used car. Ak kits could be had dirt cheap.

I havent used those particular projectiles but hornady projectiles normally produce a faster FPS over the same weight projectile from a different manufacture of the same dimensions. The hornady copper is soft and slick. Which means you have to download to a lighter charge even more which i dont like to do since i load my subs to stay in the transonic range.
I have never had it happen but have heard about getting flashover from too lite a load and having the gun explode.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top