Thread: Loading 7.62x39 subsonic from steel cased factory ammo

I'm just curious - still haven't decided to get into reloading yet - but let's say I wanted to make a batch of subsonic load out of factory steel cased ammo with 125grn projectiles, for used in a 16" suppressed bolt gun.

Could I pull the projectile and then:

1. Reduce the powder charge and use some polyester wadding to keep the charge against the flash hole; OR
2. Load with a more appropriate powder that uses the case capacity but keeps the load subsonic

(Not intending to reload the steel case after firing.)

The intention behind this is to keep the overall component cost low, and achieve subsonic for close range pest control <100m.
I'm aware of 300BLK but given the availability of 7.62x39 I thought this idea might have some merit.

Let me know if this is a bad idea / why / or possible?

Number 1 depends on the powder, apparently reduced charges with some powders can be dangerous.

Pulling the projectile probably stuffs up your neck tension, so it may not even hold the projectile when reseated.

dumb idea....1 cause subsonic has to be spot on or will wound animals
2 cause reloading in steel cases is problimatic
3 cause the projectiles will likely be very hard so at subsonic speed will be akin to fmj
4 cause the ammunition will kill 1000 times better as it is.....
if you want subsonic stuff to try...get some made up properly or buy some...try it before you attemp to recreate it...awesome for plinking and close small peskis but it has big downside when yo uget it wrong.

OK so I used to pull military fmj projectiles from steel case and swap to soft point. Worked fine but the sporting projectiles were soft jacketed lead and the FMJs were steel jacket so hard. But you still need a bullet puller and reloading press so then you can almost reload. You just need a primer tool and scales.

Reloading subsonic loads will require removal of the original powder and using different powder like Tail Boss, shotgun powder or similar. ONLY DO THIS WITH PROPER DATA and get a reloading lesson.

Subsoinic projectiles are significantly less deadly than full power loads, you will have to get up close and go for head/neck ideally.

Originally Posted by Cigar

Number 1 depends on the powder, apparently reduced charges with some powders can be dangerous.

Pulling the projectile probably stuffs up your neck tension, so it may not even hold the projectile when reseated.

I can say from the millitary 7.62 that I decapped and re-projectiled that there was no shortage of neck tension, the steel cases are just about forged onto the projectile. However it's going to depend on each manufacturer as they don't make to SAMI specifications.

OOPS forgot to emphasise we never re-seated the factory fmj's, only new soft points.

All good points thanks. To clarify I meant pulling the projectile, changing the powder load, and then putting the original SP projectile back in. (No decapping or priming.)

But I see there could be an issue of neck tension and expansion at low velocity will likely be poor.

Originally Posted by Daniel L

All good points thanks. To clarify I meant pulling the projectile, changing the powder load, and then putting the original SP projectile back in. (No decapping or priming.)

But I see there could be an issue of neck tension and expansion at low velocity will likely be poor.

I found the "SP" projectiles in Chinese ammo relatively poor anyway (full velocity), I suspect they don't know much about making them. The Russian stuff Barnaul, is on the other hand great. Unfortunately we're unlikely to see much of that again...

Buy something that is already the size of a expanded 7.62 and that uses projectiles designed to be subsonic - eg .45ACP.

get a 300blk

There's a couple of guys in USA that are doing what you're suggesting. Google/Utube it for more info. If you're worried about neck tension just crimp it. The 7.62x39 is a great round for what I hunt, including red deer when used according to your abilities & confidence.
You'll never lose reloading.

you could replace the powder with a subsonic type like trailboss

it would be better to start with a brass case as steel is not what loading gear is made for and possibly could(probably will) damage something like the expander or seater

once you work out how easy it is to knock out and replace the primer this will become a mute point as you are basically just making extra work for yourself this way

opening a rifle bullet up and tipping some out then reseating the bullet is a recipie for an explosion, you need a different type of powder with a different pressure curve (usually a shot gun or pistol powder) but trailboss is easier again as you dont need a packer to hold the powder against the primer flash hole

Dies can handle steel cases, as a exercise I reloaded several hundred wolf steel 223 cases as a trial years ago. The wolf ammo had boxer primers so it was doable. Just neck sized with no issue although after the 3rd reloading the lacquer had worn off the necks and they flash rusted. When I went back to brass there were no wear marks or anything on the brass cases.
It doesn't sit right with me the use of bullets intended for supersonic applications at sub sonic speeds. Expansion won't occur you can of course load them back to front but my preference subsonic is a lump of cast lead can't beat it.

Originally Posted by Marty Henry

Dies can handle steel cases, as a exercise I reloaded several hundred wolf steel 223 cases as a trial years ago. The wolf ammo had boxer primers so it was doable. Just neck sized with no issue although after the 3rd reloading the lacquer had worn off the necks and they flash rusted. When I went back to brass there were no wear marks or anything on the brass cases.
It doesn't sit right with me the use of bullets intended for supersonic applications at sub sonic speeds. Expansion won't occur you can of course load them back to front but my preference subsonic is a lump of cast lead can't beat it.

thats awesome to know, I have heard forever that steel is non reloadable
Id be grabbing a bag of Roberts 151gr hollow points and a bit of trailboss if you can find it, makes for cheeper than buying bullets and they work well

@ Daniel L
I load 300 blk, 7.62x39. .44mag and have also loaded 9mm all to subsonic velocities for hunting.

I can appreciate your intentions, especially in the current climate of component shortages so please realise that
I am not talking past your question, but rather talking past the middle of your journey to the conclusion you will inevitably reach if you go down the subsonic path but hopefully saving you the cost and time of the learning experience.

Your idea works in theory but in practice it will be impractical and will not save you any money. Whatever money you spend
on this project in the original intention will be a sunk cost prior to spending money on a more reliable fit for purpose option.

Firstly as a few have stated, subsonics are not reliable for stopping animals. But they are quiet and used properly they do work. For anything bigger than a hare I prefer not to rely on subs though. I see their application as more of a ‘try not to scare other animals’ option as opposed to an ‘I can hunt in a place where I couldn’t without subs’ kind of option. I prefer to have the first one in the mag subsonic and the balance of the mag standard velocity. The rule being that if you can’t kill an unsuspecting animal with a sub then you probably can’t kill a frightened spooked with a sub.


If after reading all of the above you are still keen on having subsonic rounds for your rifle then your cheapest option will be as follows.

Collect at least 20 reloadable brass cases.
Put the word out here on the forum that your keen on having them reloaded, that you have purchased your own components but not the equipment. Offer some sort of quid pro quo (LR primers are are sure bet right now) and a friendly local member of the forum will hopefully reach out to offer you some assistance.

7.62x39 can usually be loaded with accurate subsonics using 150gr RN projectiles and trailboss powder.

I realise that what I have described is an order of magnitude more in cost than what you were originally asking about but it is the minimum cost of fit for purpose subsonics for the 7.62x39. It’s like the difference between a $500 car with no wheels or a $10000 with wheels. If you want something that works you just have to absorb the cost.

I use 30cal subs for everything these days, in 300blk
It works well on everthing from turkeys to home kill bulls

shots need to sever the spine(hard) or scramble the brain(less hard)
I site for 30m and stick to that or closer for things that matter

because Im limited to how far I can see, closing the distance to 30m is hardly an issue


its kind of like bow hunting but they die on impact