A box of the 350 Legend Sub X bullets popped up at cabelas when I was putting a order in so I grabbed them but they canceled them. I don't even know what I was going to use them for

For reference for those coming in via search, @eye-gor is working up very light bullet weight 7.62x39 subs. https://www.ar15.com/forums/Armory/762x39-mouse-farts-got-chrono-d/42-542380/



Booo. There's a stack of boxes in store of all sub-x calibers and weights EXCEPT 190gr at my Cabelas.

Yup, my slow-n-quite is for a different use case - smaller game like turkeys out to 75 or 100 yards.  Have been using the .312" Hornatdy XTP 85gr pistol bullet intended for 327 Federal and similar powered by a dribble of TiteGroup.  Rifle is a Howa Mini, so no concern about operating a gas system for cycling.

GRT wouldn't calculate for less than 3.7gr of TG, I found reference in another thread to light bullets and subs with pistol powders in x39 and so started based off that data - https://forum.castbulletassoc.org/thread/8434-90-gr-swc-in-7-62x39-w-h-tightgroup-light-load-wanted/

Not running a can I don't really care about subsonic, but I do care about the bullet performance and I want to have something left of the turkey if I have to take a body shot, so aiming for 1000fps...

GRT says 4.0gr of TiteGroup, bullet seated to cannelure (COAL of 1.75)  should give 1225fps.  

Real world numbers -

3.5gr TiteGroup - 5 shot string gave 755, 922, 869, 880, 845 for an average of 854.20 and a big StdDev of 62.06

4.0gr TiteGroup - 5 shot string gave velocities of 1011, 1004, 1013, 946 and 1055 for average of 1005.80 and a StdDev of 38.98

All charges were hand weighed from a trickler.  Have a feeling that bumping powder charge to 4.5 will decrease the min/max spread and standard deviation though it should also bump velocities up past 1100...

Wasn't working on accuracy, more of a "just don't shoot the chrono" but I did use a consistent aiming point, groups were running about 2.5-3moa.

Trajectory chart for MV of 1000fps and 25, 50, 60 and 75 yard zeros

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I have 500+ projectiles of .312 7.62x54r pulled bullets.

They are 185gr bullets and seem to be a good fit for 7.62x39 subs.

Any suggestions on powder charges?

Hoping to get this to work in my AK with a dead air wolverine.

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10.3 gr 2400 works in my AR with a 220gr bullet.

I run 12.5gr of AA1680 under a Berry's 220 and it cycles reliably suppressed in my MAK-90.  I don't have chronograph data, but it is somewhere to start.

35gr difference. Hope to find some load data closer.

Thought I had some written down somewhere

If we were talking high pressure rifle cartridges on the ragged edge of pressure limits I would agree that it would be unwise to use a recipe for a bullet so drastically different in weight, but many of the good subsonic loads with various bullet weights have similar charge weights.   It is a starting point; Chrono, or just load and fire checking for reliability, sonic crack, and accuracy.

@tao

can you run the numbers on your relaoder tool software for the following.

7.62x39mm
185gr FMJ

powders 296, lil gun & H110?

Well loaded up 5 test loads.

185gr FMJ .312

9.6gr 296

2.28 oal

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Fired the above rounds.

Some good and some bad.

Good- NO over pressure signs, No Key holing that I could tell out of 4 shots, did eject out of my suppressed ak, was subsonic.

Bad- COL is too long for magazine, Did not eject in my PSA AK 103 unsuppressed and think the over all design of these bullets will not allow for a 2.20 col.

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I did load some more shortest I can get them is 2.25-2.26.

Going to try these when I get home.

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Fired 10 more rounds today

Did not cycle in my suppressed gun with the gas system turned down to provide the greatest gas pressure.

Velocity seems to be about topped out without going super. So don’t think I can increase the powder charge any further.

No over pressure signs.

Was able to get the rds to work in a magpul Ak mag.

Sounded good.

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Didja get a crack out of the 1096 fps round?

There is a reason that I used AA1680 over 296/H110 and that is because you get a lot more gas to make the gun run.   Try to find some, or some Shooter's World Blackout.

Nope everything sounded good.

Will have to look around. Trying to use what powder I had on hand since everything is so expensive now.

Same AA1680 you used?

https://www.natchezss.com/reloading/powder/accurate-powder-1680-1lb-0560-aa16801?avad=329201_b300ee861&utm_source=avantLink&utm_medium=affiliate&utm_campaign=264429

Yes indeed.

Got 2 pounds of 1680 today. Hope to give it a try tomorrow.

Success.

No over pressure signs with 185gr FMJ & 12.5gr of 1680. All rounds cycled and were subsonic and ejected about 3-4’ away from the gun at the 1-2:00 position while kneeling.

Chrono data as follows.
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The one lower velocity reading I think was due to case neck tension. I had one round that was really loose. I did hit all of them with a Lee crimp die but think that is what caused the variance.

I bet they were nice and quiet, too.   Mine sounds like a nail gun when I am shooting them.  It has so much less port pop than my .300BLK semi auto's, but I have those tuned to lock the bolt back.

Bumping this back up.  I’ve been loading 123 gr SST bullets for regular, supersonic 7.62x39 hunting rounds.

If my RAR works out during hunting season, I think a can us in the future.

Any field reports of the Sub-X projectiles on game?

I also just got a RAR! And already love it with a can (griffin optimus medium config).

It'll be my new test bed for this subsonic experimenting, it's just all on hold while I renovate my house, sell it, and move my entire life and house across the country.

UR put up some good info on using the Berry's 220gr in x39 with 308 pills.

x39 at 6:16